[RE-wrenches] Wood gas
If you are going to do something in the 50kW range you might consider using an induction motor as a generator. I think that's what someone was recommending vis a vis hydro. I am a partner in a small hydro plant and this style of interconnection is almost foolproof. You need a simple PLC to bring the rpms up to rated motor speed, then connect, then push the rpms higher to push current. Hydro controls would work without much modification. You need it to disconnect under a variety of fault conditions - that's sensors and software. Hilton Dier III Renewable Energy Design Solar Gain, LLC Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Panels with 20.1% efficiency rating
There is a theoretical physical limit for silicon based cells around 34% efficiency, so 20% for a whole module is quite good. To get past 34% researchers have gone to multi junction cells and concentrators, but it isn't practical for our purposes. Even with that they've only gotten into the low forties. What we really need now is not more efficient modules but cheaper mounting hardware. Ground mounting is getting as expensive as modules. Hilton Dier III Renewable Energy Design Solar Gain, LLC Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Inverter back feed liability
The most frightening words I can hear from a client are, "I am an engineer." Equally alarming is "I am a retired engineer." Either way, the "what ifs" are endless. Hilton Dier III Renewable Energy Design Solar Gain, LLC Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Battery Enclosures
I'd recommend going to usplastic.com and looking at their high density polyethylene rectangular tanks. I think the brand is Tamco. They come in a variety of sizes. They are sturdy 1/4" poly. You can get fitted lids. It's easy to hole saw them for conduit. I have used them a few times for small battery banks. If necessary you could combine two of them with conduit for a larger bank. They are acid proof and neat looking. They are a bit pricey, but consider the hassle and cost of getting together materials, assembly, lining, painting, etc. Hilton Dier III Renewable Energy Design Solar Gain, LLC Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] 1000V underground wire
I'm with Chris Mason on this one. Teck 90 cable is great stuff. No more screwing around with rigid PVC conduit and solvent glue in the bottom of a trench. No more backbreaking wire pulls. It is impervious to almost anything, direct burial, concrete encasement, wet location, whatever. Just roll it out and drop it in the trench. You'll be done before the backhoe operator finishes his cigarette. The cost per foot isn't that much over wire and conduit and the time and hassle savings are huge. As you can tell, I'm a convert. Hilton Hilton Dier III Renewable Energy Design Solar Gain, LLC Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Solectria PVI 5200 mounting
Hello Wrenches, I have a perplexing problem with a PVI 5200 and I can't get to the front of the tech support line at Solectria. The inverter has the usual backplate for mounting: bolt the backplate to the wall, lift the inverter, drop the slots on the back of the inverter onto the tabs on top of the plate. Fine so far. Then the instructions say to use the enclosed lock nuts to fasten the inverter to the back plate, "as shown in figure 15." Problem: no lock nuts, no place to put lock nuts, no indication of lock nuts in figure 15. The inverter just hangs loose on the tabs. I usually use SMA inverters, which have fixed nuts on the mounting frame and matching tabs on the inverter for stainless socket head screws. Has anyone dealt with this? I can't imagine just leaving the inverter hanging there. Many thanks, Hilton Hilton Dier III Renewable Energy Design Solar Gain, LLC Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Direct burial PV wire?
I would recommend using Teck 90 cable for direct burial. It is armored and coated and rated for just about anything. You can get it in a variety of wire gauges and numbers of conductors. It makes trench installations fast and easy. Hilton Dier III Renewable Energy Design Solar Gain, LLC Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] High end batteries
Hi Mac You say that relocating the batteries is a best case scenario. I'd say that it is the minimum scenario for your continued participation. I've said it before, but the most important client is the one you turn away. If this client doesn't want to get this system brought up to both NEC standards and good sense design, then that is your signal to politely bail out. Otherwise it's just going to be an ongoing failure for which you'll take the blame. Good luck Hilton Hilton Dier III Renewable Energy Design Solar Gain, LLC Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] DPW concrete base
We never did the calculation for pole mounts. We just used the biggest base size they listed and cast on an extra foot of depth in the form of a square footer. We figured that an extra half yard of concrete is cheap compared to the cost of the digging and form setting. The cost of a 36" sonotube instead of a 32" one is minimal. Peace of mind is priceless. Hilton Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Short Circuit cell damage
Rather than that, I leave a convenient pair of connectors disconnected, overlap them by a few inches, and wrap them together with red tape. It is a pseudo lockout. Everyone on my crew knows to ask and get explicit confirmation before joining connectors wrapped like that. I have to confess that once for sheer amusement I stripped a few inches on the leads of a roughly 100V string, put on my sunglasses and struck an arc. It jumped a good inch and ate up half an inch of #8. Hilton Hilton Dier III Renewable Energy Design Solar Gain, LLC Missisquoi River Hydro LLC ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Transformer or not?
Hello Wrenches, I have a customer with questions. We had recommended a standard SMA 5kW inverter for an outdoor installation. He is an engineer, so he was looking at the specs for the transformer-less version as well as the one with a transformer. He noted that the rated max efficiency of the non-transformer unit is 3% higher, 98.5%. He also asked about the cold weather -40C option. He lives in central Vermont, which does get below the regular -13C rating. (Although less often lately) Any opinions on the relative durability or efficiency of the two versions? Any opinions from cold region installers about the merits of the -40C option? Thanks, Hilton Dier Hilton Dier III Renewable Energy Design Solar Gain, LLC Missisquoi River Hydro LLC ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Wire management with S5! Railless System
Add my voice to the “never without rails” chorus. 1) S-5 clamps are only as good as the standing seam they are on. At least rails spread out the stresses and avoid large point loads. 2) Ice likes to slide. Rails give some height above that. 3) Rail height gives better ventilation and hot weather performance. 4) Module width is never an even multiple of roofing pan width. No rails means inevitably some modules will be “diving boards.” 5) Without rails, getting the modules to an even height is a giant PITA. Takes forever. I did it once and never again. Best Hilton Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Powerwall and other Li
Has anyone calculated a lifetime cost per stored and delivered kWh for any of these lithium battery systems? From the rough numbers I’ve come up with in the past it seems like daily cycling to avoid grid use would be a dead loss. The capital cost vs capacity and cycle life doesn’t add up. Also, I know mentioning this is out of line per list etiquette, but could people refrain from including 20 preceding messages in their posts? I tend to read this on my phone and my scrolling finger is getting shorter. Thanks! Hilton Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Looking for insulated #6 bare standoff
Would #8 meet code? I thought that exposed ground wire had to be #6 minimum. Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Large off grid inverter
A tough assignment, but Daryl has the right idea. A company I used to work for did large off grid systems and would use something they called a rotary capacitor (or something like that). It was a large induction motor paralleled into the grid. It had a DC pony motor and some synchro hardware/software. The DC motor would run it up to synchronous speed and the contactors would bring it online. It would just sit there idling, drawing just enough to overcome friction and windage. When some big reactive load hit the grid it would smooth out the wobble in the waveform. If the functional motor in question doesn’t start under load, you might consider a DC pony motor to bring it up to synchro RPM before closing the main contactors. Good luck! Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] UL/CSA listed battery monitor?
Thanks for all the responses. The people on this list are gold standard. I’ll look into the various monitors. The batteries are SAFT (now Alcatel) STM-140 flooded NiCads. I don’t know where these people got them, but they were surplus of some sort. They have tested them and culled a few bad ones. I’m thinking they may have to rely on the mercy and understanding of the Canadian coast guard equivalent of an AHJ. If there are no listed monitors there should be an exemption. Ignorance of SOC is worse for safety than a non-listed battery monitor. But that would be logical, so... Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] UL/CSA listed battery monitor?
The batteries have a built in ventilation and watering system, so H2 can be vented directly outside. Alcatel/SAFT publishes detailed specs on the batteries so I think they should be able to get a reasonable result. They are kind of old school with all the LiFePo units around, but they are really durable and stand up to over charge and full discharge. I’ve used them in EVs and you can boil the snot out of them. Like an EQ every time. Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Batt Cap AGM
Hi Drake I vote for option 3: run like the wind. If you touch it you own it. With that voltage variation there has to be some deterioration, so the bank will never run right no matter what you do. Of course if you change anything it will be your fault that it doesn’t work. If anything, I’d recommend that you tell the guy his bank was installed in a way guaranteed to ruin it and that it is in fact ruined. Then lace up your track shoes and sprint. If you take the job to replace it he will always harbor a suspicion that you just wanted to make the money on a new battery bank. The most important client is the one you don’t take. Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Infinia Stirling linear alternators generators
A friend of mine worked for them. I believe they went bankrupt and/or got bought out. Seemed like the usual high tech startup management cluster_. Tech guys trying to do finance and finance guys trying to do tech. They had a good idea in that the 3kW engine didn’t require the complicated heat exchanger of larger machines. It had a linear alternator design, which simplified things as well. They also developed a cheaper mirror. Their problem was that the price of PV dropped so much that they couldn’t compete in turnkey $/kWh. There are a few orphaned arrays out there with nobody to do O&M. Unsolicited opinion: solar Stirling is a non-starter in a world of cheap PV. Stirling does have a place in small scale cogeneration. Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Vertical PVs for Comm site
Bill My customer alarm just went off. This potential client is putting in a comm site at 7000’ and is concerned about the *cost* of an inverter? I can understand the desire for reliability, and so going for direct DC. But given the logistics and engineering of a high altitude remote site I’d be cautious about doing a job for someone penny pinching on an inverter. Not exactly the advice you were asking for, but it jumped out at me. Hilton Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Schott ASE modules
I have a client with an array of Schott ASE DG-50 modules. I think they are the derated 200 watt units. A couple of them are showing some thermal cracking. If anyone knows a source for these please contact me off list. Many thanks. Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC Hiltondier @ Gmail ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Direct solar options for stock tank de icing
Daryl Thayer has the key to this: surface insulation. About 90% of heat loss from an open body of water is from evaporation. There are black plastic balls (about 5” dia) you can get to float on top in a layer. Blue foam works but deteriorates in the sun. I know we are all about electrical and mechanical solutions on this list, but whatever you do, don’t waste your money trying to heat an open surface water tank. Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Rail-less racking
I tried a rail-less system on a roof mount once, but never again. It worked roughly as advertised, but the problem was aesthetic. It was a bear trying to get the modules parallel and flat. Too many degrees of freedom and no roof is as flat as you’d wish. With rails at least the modules are lined up in one plane. I’ve seen a few no rail installations on raised seam roofing and noticed the “diving board” problem. The width of the modules never corresponds exactly with the seam spacing. Some modules end up hanging out over the last mounting points a bit too much. Also, in terms of safety, rails spread out the load over multiple mounting points, so no one point takes an extreme load and the failure of any one point isn’t immediately fatal. Rails, yes. Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Ampacity ratings for different conductors
Peter, I’d recommend 2-0 copper for this. Overkill? Perhaps, but the battery cables are probably the cheapest vital part of the system. Anything you can do to make life a bit better for the batteries will pay off. A few extra bucks for cable is a lot cheaper than one warrantee site visit. Cobra “x-flex” cable is MTW THW fine strand, NEC compliant, and easy to bend in small spaces. Hilton Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] MLSD module level shutdown
There’s a buried-in-plain-sight issue here that has bugged me for years. In the bad old days we had to hard wire into J-boxes on the backs of modules. A pain, but it meant that, if necessary, we could install conduit from the module to the combiner box. Now we have convenient pigtails. However, we are stuck with #10 PV wire hanging under the module from the box to the nearest attachment point. There are all sorts of trays and wire management systems, but there’s always that one loop of wire hanging in the open. I know that the module industry has near zero margins as a commodity market. Perhaps one manufacturer could differentiate themselves by making a module with either 1) armored pigtails, or 2) provision for some kind of conduit starting at the J box. I’m thinking of all the various back covers installers have to improvise on ground mounts. I’m thinking of squirrels and ice dams. Why can’t there be a module with the equivalent of Teck 90 cable on it? Maybe I’m just being naive. Hilton Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
[RE-wrenches] What would you do/say?
I’ll say it again: The most important clients are the ones you turn away. The penny pinching, pound foolish, never satisfied, paranoid, DIY-without-asking, ear bending, time sucking, slow paying nightmares that we have all had. The key is to see the warning signs on the way in, a skill that comes from grim experience. The “can you cob this back together for $200?” job is a non starter. Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
[RE-wrenches] 32v battery options
This is some lateral thinking, but is that 1940s pump one of those basement piston pumps with a motor and belt drive? If you run into issues getting a 32v LI pack, maybe consider replacing the pump motor. With the right rpm and hp those old piston pumps work fine. You’d have to also boom the VFX 3232, but it would modernize the system. Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
[RE-wrenches] Exploding RSD
This may be a bit out of the usual path for this kind of complaint, but… The NEC isn’t law in itself. It is written by a private entity (NFPA) and adopted by municipalities and states. They can adopt whatever version they prefer. It’s within the rights of any jurisdiction to adapt or amend the NEC as they see fit. Rather than grind through the NEC process, maybe you could go to a friendly legislator or city council member and say “The RSDs are a bigger threat than what they are supposed to guard against. Delete that part.” No idea whether this would be harder or not. It might also have the salutary effect of influencing the NFPA to speed up the process of correcting mistakes. I do get the impression sometimes that the process is “Here’s an experimental piece of hardware made by only one manufacturer that solves a problem that will happen less often than this hardware failing. Let’s mandate that.” Hilton Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
[RE-wrenches] Transmitting 15kW 3600ft Off Grid.
So you have a client with clever ideas - my deepest sympathies. The five most frightening words from a client are “I am a retired engineer.” DC transmission is theoretically more efficient due to the surface conduction effects of AC. However, this is only true in a practical sense at utility/megawatt scale. At residential scale you will have losses in the electronics at either end that will negate the wire savings. Get some toroidal transformers and go to 480 and back. Fat wire is kind of expensive, but really it’s the trench (and these days, pvc conduit) that cost the money. Fat wire in conduit is solid state and will never blow a capacitor. Transformers, if not overloaded, last. On that last point, 2x oversize the transformers for the load. There will be “mission creep” while you aren’t looking. “Oh, we didn’t think that half a dozen 1500 watt resistance heaters scattered around would make any difference.” Good luck. Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
[RE-wrenches] Transmitting 15kW 3600ft Off Grid.
I didn’t really register the distance on the first look. These days, 3,600 feet of 3” PVC conduit is going to knock you back ~$18,000 to start, plus trenching and cable on top of that. I agree with prior comments that it would be cheaper to put in a new system. Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
[RE-wrenches] Well siphon?
You have 300’ of head on one side of the crest and 700’ on the other. That’s 129 psi on one side and 301 psi on the other. Turn either of those pressures into suction and water would boil at room temperatures. Aside from pipe strength, any siphon would be limited by that. Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
[RE-wrenches] Water Pumping 24/7
Here’s a lateral take on this. A 500 gallon poly water tank is far cheaper than the batteries needed to fill it. Years ago I rigged up a seasonal pump system for a man who had two ponds on his property. The lower one was well fed by a spring but the upper one wasn’t. I used a 200 watt DC piston pump and a couple of modules with a linear current booster. A couple of breakers but no batteries. It just chugged away quietly all (moderately sunny) day, filling the upper pond. Using a positive displacement pump is key for minimizing power requirements. At 300 feet that’s about 125 psi, which is not out of line for a piston pump. Fill a big poly tank and pressurize it with a small DC diaphragm pump if necessary. Simple, efficient, cheap. Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
[RE-wrenches] Water pumping 24/7 addendum
Forgot to add: I’m talking about the belt drive piston pumps out there so you can install a low voltage DC motor if you want. Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
Re: [RE-wrenches] RF interference XW
The only time I ever dealt with this it was bad grounding in the house wiring. Same deal, AM radio interference. I can't remember whether it was a soft ground or a ground loop, but that's where I'd look. Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Remote SW control
A friend of mine has an old Xantrex SW 4024 installed in a less-than-accessible location. He's looking for one of their remote control and monitoring panels. If you have one of these kicking around, or know of one, please contact me off line. Many thanks, Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Inverter Ramp times
For grid frequency regulation on a larger project you might want to look at Beacon Power flywheels. They produce a large carbon fiber flywheel that can put out as much as 250 kW for short periods of time. It isn't a long term storage solution - more like a huge capacitor. They list cloud mitigation for PV as an application, as well as ramp mitigation for wind. http://www.beaconpower.com/solutions/other-flywheel-applications.asp Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Teck 90 cable
I asked this one last year and got a few "That's interesting" responses, but nobody actually came up with an answer. Perhaps it was too obvious. I have been looking at Teck 90 waterproof metallic armored cable as a possibility for DC wire runs. This is the stuff: http://www.onestopbuy.com/omni-wire-cable/T30804-40643.asp It seems to be roughly the cost of wire and conduit and a lot easier to run. It looks versatile: "Suitable for use in ventilated, non-ventilated and ladder cable trays, direct earth burial or raceways, and for exposed or concealed wiring in wet, damp or dry locations. Suitable for use in wet or dry locations when installed in accordance with the NEC." The question is, would this stuff be acceptable code-wise for metallic-contained interior DC wire runs per 690.31 (E)? You'd think so, but I'd want to be sure before buying a reel of this stuff. Thanks, wrenches! Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] outback fx series inverters
It's a sad fact of life that people will attribute their ills to whatever is new, strange, or emotionally unappealing to them. In Vermont right now the woo-woos are afraid of wireless internet routers, wireless smart meters, and wind turbines. You have several choices. Call their game - tell them that you are sorry that they feel ill but that scientifically speaking it can't be from the inverter. Inform them of all the studies showing that people can't actually feel EMF or any kind of RF (short of sitting inside a radar dish and cooking). They should look elsewhere for relief - like a good therapist. If they are offended by that then maybe they will find another installer to bother and your life will be improved. Play their game - Faraday cage the thing or whatever the quacks want you to do. Charge full boat and a half for that kind of nonsense. Play your game - figure out something easy to do, attribute the EMF to that, and do it. I once had a potential client (luckily I didn't get the job) ask for a copper box around the batteries to reduce the "harmful waves." I assured her that she was somewhat misinformed; if there were any waves to be emitted, that they would come from the cables between the batteries and the inverter. All I would have to do is wrap the cables around each other in a spiral and the waves would be canceled out. She was satisfied with that. It was just my confidently expressed mumbo jumbo instead of hers, and it would cost her zero as opposed to a copper box. (Actually, widely spaced battery cables can be a source of RFI, so I wasn't totally spoofing her.) Good luck, Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] PV-direct electric water heating
A friend of mine lives off grid with PV and wind. He added a shunt-type controller to his battery bank and connected it to a DC heating element in his hot water tank. Below a set voltage the element is dormant. When the battery bank hits a high voltage (at the end of a particularly sunny day or during a windy spell) the element comes on. That way, instead of just a PWM shutoff and wasted energy, he gets some benefit. I wouldn't deliberately install PV just for hot water, but in an off grid situation where the excess would go to waste, it makes sense. Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Battery boxes
Take a look at www.usplastic.com and check out their polyethylene tanks. TAMCO is one brand I have used. A 36" x 20" x 20" tank will hold four large-ish batteries (L-16 or similar) with room to spare. The lids need some foam tape for air sealing, but otherwise they are acid resistant and remarkably strong. They look tidy and are easy to drill into for conduit fittings, hinges, latches, etc. I've used them a few times for small 4 x 12V battery banks, but you could link two of them for 8 x 6V. Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] PV-direct electric water heating
I believe my PV-water-heating friend has an Outback in diversion mode, so the charge profile is stepped, as Conrad noted. He has a 4 kW PV system and a frugal household, so in the summer it takes care of about a third of his DHW needs. Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Defective modules
Greetings wrenches, I'm sure many of you have seen this article in the New York Times: http://www.nytimes.com/2013/05/29/business/energy-environment/solar-powers-dark-side.html?hp&_r=1&; I have already gotten an email from a panicked client asking about canceling his project. First question: Has anybody dealt with defective modules lately, and if so, what brands? Second question: How much does this affect first-tier manufacturers (Trina, Suntech, Yingli...) and how much of this is "no-name" brands? Third question: Is this restricted to a particular technology such as thin film? And the big question: How do we deal with this? I can imagine the fossil fuel and nuclear industries promoting this story with enthusiasm. Thanks, Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Defective modules
Greetings Wrenches,
I looked at the article a bit more closely and a crack emerged. The
article mentions two Spanish projects that were tested and the modules
had a 34% "defect rate." I looked at the study (linked in the article)
and what they were talking about was thermographic defects - hot spots,
not absolute failures. They didn't specify how relatively hot these
spots were, either. They noted that the modules by that manufacturer
("E", no names mentioned) had a power loss rate over three years that
was 0.9% greater than others. None of the modules in the study lost more
than 4% in the first three years. No mention of absolute failures.
Allan Sindelair's and Jim Duncan's points about vertically integrated
companies are good. Better chance of survival and better control over
inputs.
Hilton
--
Hilton Dier III
Renewable Energy Design
Partner, Solar Gain LLC
453 East Hill Rd.
Middlesex, VT 05602
Tel: 802-223-6652
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[RE-wrenches] Module testing
There is a university in Switzerland that did some detailed real-world module testing. Here's a link to the department: http://www.supsi.ch/isaac.html I don't have time to search for it now, but they used to have an online library of papers in pdf format outlining the 0-15 month output degradation for a few dozen modules. The would alternately flash test and expose modules over the 15-month period. I remember that the Sanyo HIT modules did very well in terms of kWh/kW(STC). Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Orphan Dankoff pump - controller?
Hello Wrenches, I got a call last week to go out and look at a DC pump that had stopped working. probably hit by lightning in our recent spate of thunderstorms. The pump is a Dankoff 24V ETAPump. The controller that got popped was a more recent style of controller that uses a normal pressure switch. I replaced it with their old spare controller, which uses a pressure switch that closes when the pressure goes high. Luckily they still had that switch. The older style controller was cranky and had to be reset on a regular basis, so they are looking for another controller like the popped one. They don't seem to exist anymore. I know that Dankoff got bought out by a bigger company (Conergy?). Is there a controller for the old ETAPump being sold under another name? Is there a compatible controller from another company? It seemed to be one of those units like the Lorentz that turns 24/48 VDC into some kind of 3-phase power. It also has a pressure switch input and a low water input. Thanks. Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] outback fx service work
Another tip for working on the Outback: Use 9V (smoke alarm size) batteries ganged together to create test voltage for the inverter. They can be joined "head to tail" to get enough voltage to turn the thing on and have it self test, but if you screwed something up the amperage isn't enough to smoke anything. Good luck. Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Tri Star MPPT
What you have there is a set of completely hammered batteries. It sounds like an off-grid system with parallel strings of batteries of different ages being chronically undercharged., which is the renewable energy equivalent of a car full of teenagers with guns and whiskey. Something bad inevitably happens. I'd recommend that you get an automotive style battery load tester and clamp that on to each one in turn. Measure the voltage with your multimeter, because those load testers have iffy analog meters. I'll bet one will collapse under load. Does this customer also have a generator? Sometimes with undersized PV arrays and a generator you get a "gorge and starve" charging pattern. The customer lets the batteries get totally flailed and then grudgingly goes out and starts the generator. The batteries get blasted with high amperage for a while, shedding positive plate material, and then get starved again. Perfect storm. Tell her that she needs a new set of matched batteries. If she balks, politely tell her you can't help her, and let someone with less judgement deal with it. Good luck, Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Inverter for UPS
Hello wrenches, I need a UPS for a small hydroelectric power plant. It will be handling controls, so it doesn't have to be very large. 300 watts would be overkill. I'd get an ordinary packaged UPS, but I need to hard wire the AC output. What I'm looking for is the smallest *reliable* hard-wired inverter/charger I can find. Preferably sine wave. Not one of those auto parts store models. Any ideas? Thanks, Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] 2500 W inverter for $300
What your customers will find is that these auto parts store inverters only reach their nominal ratings with resistive loads. When trying to start a motor they exhibit a fraction of their rated power - too much reactive load. Same goes for anything with a transformer or power supply. Also, if you take the cover off of one you will be unpleasantly unsurprised at the construction and workmanship. I've seen one with a "heat sink" for the transistors that was a paper thin piece of aluminum angle. You have to think that at $300 for 2500 Watts (supposedly) they used the very cheapest discrete components they could source. Talk them down off the ledge. Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] PV Assist - customer management
This: "PS: the "good" customers are not necessarily the greenest people, they are the ones that reduce consumption as best they can, do their homework, trust me and pay on time." I'd add, "and have a grasp on the realities of the situation." There are people who will never grasp that you can't consistently leave a battery at 90% DOD for a week without shortening its life. Or that solar irradiance drops in the winter. You can recite the facts to them and they will nod and look like they are absorbing information, but memory fades and a month later they will complain about the exact thing you explained to them. William, whatever you do with these clients, I recommend that you write a short disclaimer about battery life and have them read it and sign it. "I acknowledge that this particular design and implementation is not ideal for long battery life. I do not expect the battery banks as installed and used to last their advertised cycle life." Or something like that. When they ask why you aren't designing it differently, quote them the price for a system that would preserve the batteries. Pick their jaw up off the ground for them, hand it back, and make them sign. At the very least it will put them on notice that the reality of the situation is not ideal. Good luck. Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] SHW - parallel tanks
Kirk, After some experience with exactly the complaints you have been getting (the sound of the boiler running drives people nuts), I wouldn't install SHW on an indirect/boiler system without a bypass. It's just an extra pipe and two ball valves. A pipe with a valve going from the output of the solar tank to a foot or so after the hot output of the indirect tank. The other valve goes in between that tee and the indirect tank. Have them turn off the boiler in the summer, close one valve and open the other. The customers who care will do it. Without the bypass you'll get people who turn off their boiler in the summer and complain because they have to run the entire contents of the indirect tank out the faucet to get hot water. You can add a little backup to this by sticking a 1400W electric element in the solar tank and setting the thermostat to 120F. That way, even in a rainy summer you'll never get a call. Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 Tel: 802-223-6652 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] question about pole mount interconnection
We just did a 4 pole installation using DPW top-of-pole mounts. We used Teck-90 armored watertight cable between the poles and from the poles to the house. The Teck-90 spiral wound metal flex conduit with an everything-resistant black sheath on it pre-stuffed with just about any combo of wires you might want. We cast 2" PVC sweeps into the 36" dia. sonotubes so the cable could enter underground and come up next to the pole. We put PVC end caps on the tops of the sweeps with cable holes in them, just for neatness. Teck-90 is a revelation. We laid out and buried a double run of 100 feet of the stuff in the time it took the excavator to go along the trench. He never got out of the cab. We get it on a 500' spool and mount the spool in the back of a pickup. Then we just run off however much we need, cut it to length, and throw dirt on it. We got it from Graybar for slightly less than the price per foot of the equivalent wire and PVC conduit. I had been meaning to write a post on here about it. We also just did PV on a barn roof and did the spool-it-off-and-clip-it-up routine. Made the run from the roof to the inverter on the north side first floor in about 40 minutes. No conduit bending. The end connectors are kind of pricey, but the time saved is huge. Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Teck 90
William, We get it with two pairs of color coded #8 copper and a #10 ground. Off the shelf you can get #14, #12, #10, #8, and #6 and on up to 500 MCM. The 14-10 go up to 10 conductors and the 8 and 6 go up to 4 conductors. Here's a URL, not the cheapest place, but to give you an idea: http://www.onestopbuy.com/wire-cable/Product-Price-Code-TK-40629.asp Graybar had the best price for us. You can also get it custom in big quantities from some manufacturers. If you support it every 18" or so it stays straight. The end connectors are a bit of a PITA to assemble. The key is to cut the end of the armor cleanly and as directed and then disassemble the connector and put it on piece by piece. Takes a couple of minutes. Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] To stack or not to stack? Off-grid 240V
Hello Wrenches, I have an off-grid client with a 24V system and an old Xantrex SW4024. He wants 240VAC capability with enough oomph for sometimes making a cut with his 3 hp table saw without starting the generator. I am looking at Apollo, Magnum, and Outback inverters. I'm most familiar with Outback. I have a couple of installations out there with stacked 3.6 kW Outbacks. However, the Apollo marketing promises that their 3.2 kW inverter will start a 3 hp motor. Will it actually, and is this a good idea even if it can? I'd appreciate hearing about your experiences with 240V Apollo units, stacked Magnums, and stacked Outbacks. I know from experience that the Outbacks require some hundreds of dollars of extra fittings and electronics to make a proper stacked installation. How about Magnum? Any comments on reliability? Many Thanks, Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Off grid heat pumps
I've done a couple of load profile studies for heat pumps and solar and unless the load is primarily air conditioning it's a bad match. Ground sourced heat pumps in general only pencil out if there is a big air conditioning load. The only time I'd recommend a heat pump with an off grid system is if there was a wind turbine that massively over-produced in the winter. The PV production curve is exactly backwards. The clients should take half the money they would have spent on installing a heat pump and do a thermal efficiency/passive solar retrofit. Better ROI. Best, Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Acid containment
US Plastic (usplastic.com) carries polyethylene tanks used in industry for acids. You can get them in various sizes - 24" x 36" x 20" deep and larger. They will custom heat weld whatever you want. Kind of pricey (~$300) but heavy duty. Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] line shading
Hello esteemed wrenches, I have a client who wants a ground mounted array. He has field with his power line running east-west across it to a pole with his meter on it and then buried conduit to his house. Because of the size of the array it makes sense to do a line side input at the pole. The field slopes down to a river, so we would like to stay back from the lowlands to avoid flooding and saturated soil. The problem is that the really high ground is to the north of the power line. Is there any received wisdom out there about how far to put modules from a power line to avoid line shading? I know that we can check the solstice sun angles against the wire height and top and bottom heights of the array. But if the array ends up inside that angle range, how far away does it have to be for that shadow to interfere into a non-issue? Thanks, Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Clients and mates
After reading this I get the idea that there should be an aptitude test for potential off-grid clients. "No, I'm sorry, you failed basic battery maintenance. You'll have to go with sealed batteries and a service contract." I think we all eyeball clients with this kind of thought in mind. I had an off grid client with a 48 volt battery bank, the usual 8 each 6 volt batteries. He was dissatisfied with its performance so without consulting me he added four more batteries to the string. Then he called me to complain when that set was truly hosed. I went to his site, not knowing what he had done, and opened the battery box. Y'know those old wood-block prints of angry samurai warriors with squinted/bulging eyes? I must have looked kind of like that. I'll say it again: The most important client is the one you turn away. -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 Tel: 802-223-6652 ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Stolen modules, what to do?
On a ground mount you could mount them from the back with stainless pop rivets. Unirac has back mounting tabs that are supposed to be fastened with 1/4" hardware, but long pop rivets would fit. I'd recommend an air-powered rivet gun for that. It won't stop the frame sawing, but then what will? Obvious video cameras (real or fake) and a sign saying "You are being videotaped" is the best aside from that. -- Hilton Dier III Renewable Energy Design Missisquoi River Hydro, LLC Solar Gain LLC ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Sunpower micros and mysterious outages
Friends of mine got a Sunpower system installed last year. Ever since then they have had intermittent problems with circuits in their house going dead. The array is 14 each Sunpower SPR E20 327 C AC. The array is mounted on a corrugated steel roof on their garage, about 20 feet from the house. What happens is that a circuit in their house will either go dead or brown out so lights barely glow. This happens to various circuits and at any time of day or night. The rest of the circuits will work fine and the event will last an hour or two. The breakers don't trip. They have had two different electricians there to check the house wiring and it's all solid. Any ideas? Some kind of metal roof capacitance? Many thanks, Hilton -- Hilton Dier III Missisquoi River Hydro Renewable Energy Design 453 East Hill Rd. Middlesex, VT 05602 Tel: 802-223-6652 ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Apparent Power's reasonably smart inverter
Chris, I just read a white paper on the Apparent Power site, and it appears that they have an inverter that is one step smarter than your average bear. The key quote: "The inverter changes the DC input from the solar panels to AC, senses the phase angle lag or lead on the output line, and compensates by changing the phase angle of its output current with respect to the grid voltage, until the current and voltage are in-phase." So it can sense how far off the voltage and current curves are and push in a wave form combo that attempts to get the grid waveform back to unity power factor. How successful it would be depends on the size of the solar/inverter array compared to the other loads and generators on the grid, but it is pushing in the right direction. I used to work for Northern Power Systems in Waitsfield, VT. While I was there they came up with a really smart inverter that did the same thing only more so. I think the working name was the Power Router. It read the grid waveform about 1000 times per second and modified its output at the same rate to attempt to create a perfect unity factor sine wave on the line. With enough Power Routers on an isolated grid you could see garbage wave turned into lab grade sine wave. Sadly, it never became a product. This technology is more simplistic, but I'd say you have a good case to bring to your utility. Send their engineers to the Apparent Power website and let them geek out with the white paper: http://www.apparent.com/downloads/TheMathematicsOfDynamicPowerManagementOnTheGrid.pdf Remember that with utilities it's always a fight until they realize the benefits. Best, Hilton Dier Ray, The idea that the utility in an island is seeing an advantage to having PV on the grid is a huge concept for me. As I am based in a small island with a utility that is scared of solar pv installations, this concept is tremendous ammunition for me. I am also fascinated by the idea of PV installations as a corrective power source, the possibilities for this are tremendous. If there is any more information anyone can offer on the impact of PV on an island grid, I would be very interested to hear. I am going to write an article on my blog and in print on how other islands are benefiting from solar, so anything you can tell me will help to build this story. Chris Mason -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] AC Coupled
Larry, I have run into similar situations. The simplest thing is to wire the Sunny Boy 6000 into a breaker in a small dedicated box on the *grid side* of the transfer switch. Grid present: feeds back normally Grid absent: interacts with Sunny Islands Grid absent, genset on: Sunny Boy cut off from the system I'd assume that they wouldn't lose much, if any production from the PV, since they'd probably be running the genset for short runs, at night, or in cloudy weather. Best, Hilton Wrenches, I have a client with a 4.6 kw grid tied system using a Sunny Boy 6000 inverter. We have AC Coupled to that system with 2 Sunny Island 5048's and 8-Concorde SunXtender 3050T 6 volt batteries in series feeding an essential load/critical load sub panel. The wiring to the sub panel from the Sunny Islands is #6, the max wire size that can be used in the AC 1 and AC 2, in and out, of the Sunny Islands. The 2 pole breaker at the sub panel is 70 amps ( 56 amps feed through current x 1.25 = 70 amps ). This allow the 4.6 kw solar system and the Sunny Boy 6000 to act as a micro grid and charge the batteries and support the loads in the SubPanel when the grid is down and still be isolated from the main service panel and the grid. We have moved several loads from the main 200 amp service panel into the essential load/critical load panel, the well pump, the refrigerator, the circulator/boiler controls for the propane fired radiant heating system and some lights and communication circuits. The main 200 amp main service panel has an integrated manual transfer switch that has allowed them to fire up the gas powered Honda generator and run all of the loads when the grid was down before we installed any systems to their home. They would like to be able to continue to do this in an extended power outage. So here is the question? In a power outage, if they fire up the generator and move the manual transfer switch in the Main Service Panel to generator, the Sunny Islands will see this generator power coming from the Main Service Panel and switch from Back Up Mode to Pass Through Mode. The Sunny Boy 6000 will send any excess power not used by the loads to the the generator (as if it was a net metering arrangement ) believing it is the grid. This would probably destroy the generator or some other disasterous scenario. So how can the generator feeding the Main Service panel be isolated from the Sunny Islands and Sunny Boy feeding the SubPanel as a micro grid in a power outage and still provide power to the loads that are in the Main Service Panel? Thank you for the collective wisdom and knowledge that this group has acquired from years in the trenches making it all happen. Larry -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Unusual Module
Kent, I had modules like those back in the early 1990s, when I first went off grid. They are designed to be wired in sets of three for 12V nominal, 18Voc. If the EVA encapsulant is a bit browned it is probably leftover from the Carrizo project, the largest of its time. The Carrizo project had reflectors to increase output but they cooked the adhesive. The owners eventually lost their beneficial rate and realized they would make more money selling off the modules than selling the electricity. Many homesteaders benefited. Hilton The label looks like a shiny piece of foil, but with light angled on it just right way the name Solarex is visible as are many words on the label template. None of the values are legible. It is a little smaller than a MSX-60. It has 40 cells that are wired in four parallel strings of ten. Open circuit voltage is about 6 volts. Shorted it put out 4 amps in bright but very overcast conditions. I suspect that it would put out 8 to 10 amps at STC. There are two j-boxes, one on each end, with very substantial terminals. It still operates, but obviously it isn't much use for charging a battery, even a six volt one. Anyone familiar with a low-voltage high-current Solarex module. -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC renewabledesign.com ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Multiple angle conundrum
Wrenches, I am talking with a potential client about a roof mounted PV array. The client has a reasonably large south facing roof, but it is broken up by a large (18' W x 16' H) shed dormer. The roof is 10:12 and the dormer is 6:12. I designed a layout that gave the dormer some room to avoid shading. The client was disappointed by how much wattage I could get on his roof. I pointed out that installing modules in the shade of the dormer was a bad idea. He is also talking to another installer. The other installer proposed installing part of the array on the 10:12 roof and part on the 6:12 dormer. The client had already asked me about that and I gave him a rudimentary explanation of maximum power point tracking and the inefficiency of such an arrangement. He asked them about that and their guy said "No big deal." He is still considering the two-angle scenario. So, how much efficiency will he lose by going with two angles? It seems like the ultimate MPPT design error to me, but I don't have a number for him to make my case. I suppose it all comes down to cents per delivered kWh in the end, but two different roof angles seems the the wrong way to go. I'd like to be able to give him a definitive idea of what he would be sacrificing with that scenario. Side note: The other installer is using the new Sunpower E20 modules. They seem to be available only from the manufacturer. Anybody have a source? Has anybody used them yet? Do they live up to the hype? Many thanks, Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Autotransformer caution
In the last list someone mentioned putting the transformer behind the pressure switch for the well pump so it won't be sitting there idling 24/7. It's a good idea, but watch out for the double surge. When the contacts close you'll get a surge load from the well pump trying to lift a column of pressurized water, but also a surge from the transformer as the coils energize. I have seen a few inverters have trouble handling that stacked surge. If the inverter is significantly oversized compared to the pump/transformer it will be ok. Otherwise you can get a time delay relay that waits a second (or so) after it gets actuator power before energizing. In that case you'd want to adjust the pressure switch to come on a few PSI higher than usual so the customer doesn't experience a momentary loss in pressure. Best, Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Boxes and bags
Here's an everyday, practical question for my fellow wrenches: What kind of bag or box do you use for your everyday assortment of tools? For years I have been carrying my cutters, stripper, screwdrivers, multimeter, etc., in an aluminum suitcase about the size of a double thickness briefcase. I call it my 90% box because it carries 90% of the tools I use regularly. It has loops and pockets inside the lid for pliers, cutters, and screwdrivers. It has a partition system in the rest with an internal lid. I think it was billed as an office equipment repairman's case. The problem is that the hinges are broken and the partitions have deteriorated to uselessness. I need a new case. This one wasn't ideal, so I'm looking for suggestions. Thanks, Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Solar flares
It's my understanding that the threat of solar flares primarily to the grid and devices connected to the grid. When the charged particles from the sun hit our magnetosphere that induces voltage in long power lines. Since we have satellites (SOHO and ACE) at the first Lagrange point in between the earth and the sun, we have real time warning of solar flare events. There are also multiple earth based solar observatories watching 24/7. An eye on the astronomical news and a simple disconnect will protect a residential system on the AC side. If a system has a long run to a ground mounted array then flipping the disconnects at either end would do the job. Even then, I doubt the amount of voltage induced in a 150 foot underground run would amount to much. The magnetosphere protects us from most of the effects of solar flares. They aren't gamma rays, after all. I haven't done the research, but I'd think that a blast of charged particles powerful enough to either induce high voltage in the short wiring within a metal cased, grounded inverter, or to literally blast the semiconductors into submission directly, would leave the owner with bigger problems than a loss of electricity. Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 Tel: 802-223-6652 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Very unbalanced DC wiring
Being DC, it's a round trip for the electrons. Fat pipe one way and thin pipe the other will work. Calculate the drop for 250' of 3/0 and add the drop for 250' of twice the circular mils of 3/0 and you have it. Offhand I'll say it is 1.875%. As for the code issue, I don't see one, as long as the cable is rated for the conditions. Hilton Dier On 5/17/2012 1:37 PM, re-wrenches-requ...@lists.re-wrenches.org wrote: Wrenches, I am doing a job for a customer installing a ground mounted array about 250' from his existing battery bank. Array is: - Vmp: 87.9 V - Imp: 47.1 A - Classic 150 controller The customer already owns (hence the choice of the 150 over the 200 or 250 controller) sufficient length for the array transmission of a heavy duty direct burial rated cable, 3 (total) conductor 3/0 AWG copper. He also happens to own sufficient length of #2 AWG USE-2 copper. My question is: is there a problem (code or practical or both) with using two of the 3/0 conductors paralleled for either the positive or negative, and one of the 3/0 conductors by itself for the other side? In this case I would use the USE-2 as the grounding jumper. The max voltage drop on the circuit using only single conductor 3/0 over this distance (and also accounting for stepping down the conductor size and array circuit conductors, etc.) is about 2.5% max, so we could live with this. That said, the customer already owns all of this wire and if I can safely shave a couple tenths of a percent voltage drop, every bit helps when you are off grid. It seems to me that using doubled cable on one side only is effectively exactly the same as having home run cables (of the same AWG) from a series strings of modules where either the positive or the negative is twice as long as the other, which happens all the time at the array. Any thoughts most appreciated! -Nathan -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Metering a whole house Outback system
Hello Wrenches, Here's a metering conundrum for you. I have a client with a dual stacked Outback 3648 inverter panel and a PV array. He has been off-grid for years, but he is now going on-grid. He is getting the Outbacks rebuilt at the factory to be grid tie compatible. As per our local requirements, he needs a meter to read just the output of the inverter. The problem is that he has the whole house on the inverters, not just a vital loads panel. He wants to keep it that way. That gives him two separate outputs, "AC Out" to the main breaker panel and "AC In(teractive)" to the grid connection. If he just puts a meter on the AC In line, he will lose track of the inverter output that goes to power the house, and he'll get his output reduced by any grid-based charging he does. There is a "green tag" method of wiring the meter to avoid this, but it is designed for two single-leg 120VAC outputs and the stacked Outbacks are putting out 240VAC on two legs. Aside from dropping $600 on an e-Gauge, is there any way to get around this? Many thanks, Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] S-5! Question
We did one direct to S-5! installation - never again. Alignment and leveling was a pain and the wire retaining clips on the discs were useless. Always use rails. Aside from the installation issues, rails will better distribute loads across the roofing seams. Without rails you'll inevitably end up with "diving board" modules cantilevered off of the clamps. But really, the most important point I can make is that the S-5! clamps are only as good as the roofing. If you look in the S-5! literature you'll find a wide variety of tension and shear force ratings depending on the brand, material, and thickness of the roofing. You are also dependent upon the diligence and skill of the roofer. How many fasteners are under there, of what kind, and into what sheathing? It's a gamble. My response is to distribute the load with as many clamps as I can. You'll find that the resulting factor of safety is not all that huge. The cost, as a percentage, is not that huge either. And you'll sleep better. Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Direct PV-EV charging: possible?
As a former EV builder, the big question that comes to my mind is the battery type. Lead acid is possible, lithium ion, not. If the EV has lead acid batteries, then a high voltage DC charge controller will work. It will have to handle voltages in the 195 range to equalize a 156 volt pack. If it is a sealed L-A pack, then it will have to reach ~185V. The problem comes with the modern lithium ion batteries. They can't just be strung together and bulk charged. They require intelligent battery management systems, generally integrated into their AC source chargers. Even a little overcharging can result in a very expensive boat anchor. Worst case, a pricey road flare - the size of your car. Finding an intelligent DC-DC converter based charger with an integrated battery management system would be tricky - custom work. Many dollars. Most of the high voltage cars have lithium packs. Given the efficiencies of modern high voltage utility tied inverters, your client isn't really losing a lot. He'd probably lose as much through a DC charge controller. Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Off-grid 1nverter replacement for 3 HP
I have an off-grid client who is having trouble with his aging Xantrex SW4024 inverter and is considering an upgrade. I need some advice. One of his problems with his present system is that he can't run his 3 HP 240VAC table saw on the 4024. He'd be content to run his generator for any long sessions of sawing, but he'd like the capability to do a cut or two without firing it up. I was thinking about stacking a couple of Outbacks. I'd like to know people's real-world experiences with the relationship between motor HP, rated inverter watts, and surge watts. How much wattage does he need to actually do the job? That is, without flailing the inverter(s) into a shortened life span. Also, how do Outbacks compare with Magnums or whatever? I have been using Outbacks for a while with good results, but I have been hearing murmurs and grumbling since they were bought out. I haven't used Xantrex/Schneider for a while and I have no experience with Magnums. I notice that the Magnums offer split phase 240. I should note that he has his inverter setup in his wood shop. I am theorizing that some of his inverter trouble could be from a tree's worth of sawdust in the case. He presently has a 24V system, but he is considering a battery replacement, which would be an opportunity to switch to 48V if necessary. The sawdust issue makes me lean towards the sealed Outbacks, but he does have a partially finished box for the inverter with filters and a fan. Opinions? Many thanks. Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 Tel: 802-223-6652 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] EMT in attic - vs FMC vs armored cable
This subject interests me as I had been considering using waterproof metallic armored cable. I can get pre-made cable with just about any number of conductors of any size, sheathed in a flexible metallic layer and then a UV resistant waterproof layer. The stuff is direct burial as well. Buying 4 conductor and ground #8 would handle 95% of my residential work. I could overkill with #6, or 6 conductor, and the savings on all the screwing around with conduit would still make it better. In bulk it's actually about the same price per foot as individually purchased wire and conduit. The thing I like about it is that it eliminates all the cutting, measuring, bending, and pulling, or in the case of PVC, stocking of fittings, measuring, cutting, gluing, and pulling. Just roll it off the reel. The question is, will the AHJ accept it for a >250VDC interior run? Maybe with the right end fittings? Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Heat Tape
With heat tape I'd be worried about uneven heating of the module surface and possible cracking. I have toyed with the idea of running a length of 2" or 3" conduit under the bottom of the modules on my shop roof. It would be capped on the end and have 3/8" holes drilled in it every foot. It would lead inside the building to a simple blower on a timer. The heat would be even and gentle. I've noticed that if I can just clean off the bottom foot or so of the array the heat gets up under the snow the whole mass comes down on the first sunny day. An hour of warm air might jump start the process. Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Fridge Recommendations
Hi Dave, It's a stretch, but consider Nova Kool. This is not a low-initial-cost option, but it can be an ultra-low energy option. Nova Kool makes a high efficiency DC refrigerator kit - just the mechanical and electrical guts. You build the box. It was originally designed for boaters who had to make odd shaped refrigerator boxes to fit curved hulls, or wanted to convert ice boxes. I put together one of these last year for the repro historic boat Lois McClure. It is disguised as a big packing crate in the hold and has 4" of foam in the walls and an airtight door seal. It uses less than half a kWh a day for 10 cu. ft.. The compressor assembly is located 12' away behind another crate. In the case of off grid residential use, your client could build a hyper-insulated (6"? 8"? 12"?) box right into an outside wall with the compressor outside. They could even incorporate a closed sheet metal air exchange box in the back to use the winter cold sink. If the box has to be interior the compressor can be located up to 12' away, or 16' with the extended kit. The whole kit costs about $1,000. Yes, pricier than a commercial fridge, but think of the cost of a depreciating generator plus fuel. Think of the extended lifespan of the battery bank. It probably works in terms of fuel, maintenance, and deferred capital costs.I've always found that it pays to spend a little more up front on the demand side management. A gag I used to use when I had a propane fridge was to set a few water filled 1-liter soda bottles out on the porch in the winter. Then I'd swap them in and out of my fridge a pair-three at a time, making it a semi-icebox. Good luck and please report back if you find a good fridge. Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 Tel: 802-223-6652 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Awkward Mid-clamps & jigs for installing or, removing modules?
I made a pair of jigs out of some two foot lengths of 20-80 (That 1" square aluminum extrusion with bolt slots on each side) and some unequal-leg angle. I cut some 1" long pieces of 3"x 6" and 2" x 3" aluminum angle, two each. Then I drilled the short legs and bolted a long and a short angle to one side of each piece of 80-20. To suspend a module I adjust the distance between the two angles, tighten them down, slide the jigs (short angle first) flat up under the bottom rail, and tip them up 90 degrees. The short angles hook on the rail and the module can rest on the long angles. I can adjust them for any module and it's a lot easier to get the array aligned. Message: 4 Date: Fri, 18 Jan 2013 11:35:56 -0600 From: "William Dorsett" To: "'RE-wrenches'" Subject: [RE-wrenches] Awkward Mid-clamps & jigs for installing or removingmodules? Message-ID: <004101cdf5a2$460a7550$d21f5ff0$@net> Content-Type: text/plain; charset="us-ascii" Single-handed mounting for replacing or installing modules on racks. My helper installing an array on an Iron Ridge rack commented (like so many of you have surely thought) that the mid-clamps are really clumsy. His suggestion was that on his, he would lengthen the rail and only use end clamps so each module would be independently mounted, removed or the Enphase replaced. Of course this would apply to UniRack and other mid-clamps too. Can anyone recommend a jig for supporting the line of modules, while they are individually being clamped or unclamped? Perhaps a long length of Al angle braced back to the rail, so the bottoms of the modules can sit in a straight line while they are being clamped. Even a couple sliding Z-shaped spring hooks that can support the bottoms might work one module at a time as long as the rail is s -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 Tel: 802-223-6652 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Module holders
In a recent discussion of the awkwardness of a PV mounting system I described module holders I made. Somebody asked for a photo. I got around to taking a picture of them: http://farm9.staticflickr.com/8326/8403507927_73a23357a8_m.jpg 80-20 and aluminum angle - do it yourself in an hour. I use both under one module, then shift them over when the first module is clamped from one side. You could cut them out of 3/4" ply for a particular job. I like these because they are adjustable. Hope this helps reduce rooftop profanity for someone. Hilton -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Battery EQ question, Xantrex XW system (Dan Fink)
Dan, What Alan said. The most important client is the one you turn away. The fact that the previous installer "fled" and that the client refuses to use a generator makes an alarm go "ah-OOO-gah! ah-OOO-gah!" in the back of my head. I just walked away from a client after five years of repairing their boneheaded mistakes.* I should have seen them coming on the way in. Having repeatedly beaten their system into a quivering heap for years they are now "disappointed" with its performance and refused to pay my last invoice. I was there for them on short notice, on weekends, gave them sympathy discounts, the works. They think I'm a bad guy. Conclusion: There are some people who are too mechanically incompetent for off grid living. You cannot make them happy. Say, "I'm sorry, but if you won't use a generator or pay for a maintenance contract, I can't help you." Really, walk away. "Gorgeous" and "so close" are the cheese in the trap. And yes, a psychology degree would serve any of us better than an EE degree 99% of the time. Good luck, Hilton * Client: "The system wasn't holding a charge when we had three toasters and two coffee makers going, so I added four batteries on the end of the pack." Me: "Um, your system is 48 volts - eight six-volt batteries. Adding four batteries makes it a 72 volt battery pack. Your system can't charge that high, so that's why it died." Client: "But there are four more batteries. That's another 50%." Me: "Remember how I've asked you to call me before you do stuff? Let's go through this again..." -- Hilton Dier III Renewable Energy Design Partner, Solar Gain LLC 453 East Hill Rd. Middlesex, VT 05602 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] has anyone ever had this happen?
Hi Jay, I'm with Daryl on this, except I'd say RUN AWAY, right now, no matter what. When a potential client in a problematic location starts dictating oddball terms right off the bat, that's more than just a problem with the contract. It's a telltale that something is wrong with the whole situation. It speaks to the attitude and motivation of the client. If they are that picky about the pricing they will pick you apart on everything you do. Most people are fine, but some clients are just born dissatisfied. Even if they suddenly agreed to all your terms I still wouldn't take the job. Best of luck, Hilton -- Hilton Dier III Missisquoi River Hydro Renewable Energy Design ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Mounting on rock
If it were me, I'd buy a case of Red Head A7 anchoring adhesive: https://www.fastenal.com/products/details/0228790 Get an engineer to do the static load calculations and design the attachment disk and bolt pattern. Weld a big disk with holes around the edge and gussets to the bottom of your pole. Drill however many holes of whatever size the eng says into the rock and put in some B-type threaded rod with the A7. Washers and nuts above and below the disk to level it. Pack underneath it with concrete if you want. Granite is a great base if it is flat and solid. ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] UL/CSA listed battery monitor?
I have a client who needs a monitoring system for a 48V nominal NiCad battery bank on a boat. It's 4 parallel strings of 6V batteries. (Not ideal, I know) It's a passenger boat in Canada so all electrical devices need to be UL/CSA listed. None of the Bogart Engineering monitors are listed. Any suggestions appreciated. Thanks! Hilton -- Hilton Dier III Missisquoi River Hydro Renewable Energy Design ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Infinia Stirling linear alternators
Hi Larry, My friend might have actually supervised the installation of that array. I don't think he has any documents. Even if he did, I don't think they would be any use in refurbishing the array. Every last part in those things (aside from bolts) is specific to the machine and unobtainable. Their tech might have been bought by this company (https://www.qnergy.com/) but I'm not sure. Hilton -- Hilton Dier III Missisquoi River Hydro Renewable Energy Design ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Supporting heavy flooded batteries
A suggestion: McNichols Corp, among others, deals in pultruded fiberglass extrusions, including various grids. Pultruded fiberglass is strong and acid resistant. It comes in just about any shape that you can get in steel, including sheets, C-channel, angle, and I-beam. I've even seen pultruded bolts to put it all together. I've never had the opportunity to use it in a battery box but it seems like the right stuff. A number of industrial supply companies sell walkway decking in this kind of material. -- Hilton Dier III Missisquoi River Hydro Renewable Energy Design ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Charging a Bolt with an SW
The issue with EV chargers is that they create a lot of reactive power. Think of it as "slosh" in the waveform. That means that charging at 2,000 watts sloshes a lot more than 2kW through the cable, plug, outlet, and from the inverter. If you've got a reasonably good sinewave inverter the charger will like it fine. However, the inverter might not like the charger if you cut things too close. Make sure to have a lot of top end left in your inverter. Always use a transformer based inverter. The SW series has a big chunk of metal in it, so that's good. At 120V the Bolt will only draw 1440 watts max. An aftermarket Bolt 240V charger can draw up to 32 amps. That's 7.7 kW, so too big for an SW. Treat it more like 40 amps. The OEM 120/240 EVSE (smart charging cord) that comes with the car can draw 8 or 12 amps at 120V or 12 at 240V. Assume that the 8 amps is really 12 and the 12 is really 15 or a bit more. I have seen 15 amp plugs and outlets with the hot prong melting plastic around it. The plug on the OEM EVSE is 20A rated but make sure your outlet is as well. -- Hilton Dier III Missisquoi River Hydro Renewable Energy Design ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Tesla Powerwall 2.0 - Experience?
Greetings, Wrenches, I have an off-grid client who has been reading the buzz about the Tesla Powerwall 2.0. I have been reading the data sheets and manual for it and it appears to be AC coupled only. There was talk of a DC input version, but apparently that fell by the wayside. I try to be agnostic about technology, and I'd be willing to subcontract a Tesla-approved installer if, in fact, this was the best solution. Does anybody have experience using the Powerwall 2.0 in an off grid PV system? Is it AC coupled only? Can it take generator power without barfing? What is the lead time on these? Many Thanks, Hilton -- Hilton Dier III Missisquoi River Hydro Renewable Energy Design ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Metal roof
I'm with Jerry Shafer on this one. S-5 clamps with rails work well without punching holes in the metal roof. If the roof is fastened well to beefy steel C channel it should be fine. The S-5 clamps themselves are stronger than the roofing. -- Hilton Dier III Missisquoi River Hydro Renewable Energy Design ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
[RE-wrenches] AC V DC RE: electrolysis
To answer the original question, AC will not cause electrolysis. The electrons must be pushed consistently in one direction for that. That’s why people use battery chargers to power electrolysis systems for de-rusting old iron artifacts. In fact, pipeline operators will run a low amp DC current in the “wrong” direction to prevent corrosion. You could just put a standard furnace control 24v transformer on the output of the generator and it would activate the relay. Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
[RE-wrenches] Today’s mindbender
I just had an off grid client have his cousin install an electric water heater and wonder why his system went down overnight on low battery. But that was just typical newbie off grid mission creep. You have a full on disaster there, right from the get go. A client with unrealistic expectations that require extraordinary departures from normal practice. I mean, driveway melt, hot tub, AC, multiple refrigerators, zero planning; it sounds like an elaborate joke. I have learned and relearned the great truth that the most important client is the one you turn away. That demanding, picky, unrealistic, clueless, careless deadbeat that will eat your time, money, and emotional energy. This is one where you walk away. If you somehow manage to install 14 kW and surmount the amperage/ service entrance problem (Mo’ amps, mo’ problems) I will bet the rent that this client will be perpetually dissatisfied. He will crash his battery bank in the first outage. Call the client. Say “I’m sorry, but I can’t figure out a way to make this work that satisfies my standards. I don’t think I can make you a satisfied client.” Move on, happy in the knowledge that you dodged a tactical nuclear weapon. Best of luck, H Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
[RE-wrenches] SMA alternative?
Esteemed Wrenches, I am a long time fan and installer of SMA string inverters. I have a project right now which is a ground mounted array of 12 Trina 380s, so just over 4.5 kW. SMA inverters seem to be unavailable for the foreseeable future. What would be your recommendations for an alternative? I know it’s unfashionable, but I’m not a fan of micro inverters. Thanks, Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
[RE-wrenches] Onboard PV Charging Kit for Electric Vehicle
My first question is the voltage of the truck’s battery pack. If it’s below the 118V of the array you should charge the pack directly with just a charge controller to minimize losses. There is absolutely no reason to add another battery pack separate from the drive pack. The drive pack is undoubtedly heavy enough without a second pack that doesn’t contribute to propulsion. The inefficiency of solar>controller>battery>inverter>charger>battery would be a significant loss. If the propulsion pack is higher than 118 volts you have a problem. You’ll need a 1kW DC to DC converter that will boost the voltage to some value well above the pack voltage. I’m imagining that this would be difficult to find. Then you would need a charge controller that would tolerate the output of the DC-DC converter. Maybe just a voltage tripped relay and a DC contractor. It’s a slick looking rig. Good luck. Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
[RE-wrenches] LG Chem RESU warranty
Just as a bit of context, LG is in the middle of a gigantic warranty recall and replacement of every 2019-2022 Chevy Bolt battery pack. As far as I can tell the recall is overly cautious, but it’s good that they are stepping up. It’s not an excuse for bad service, but an explanation for why there might be a shortage of both batteries and attention. Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
[RE-wrenches] gravity storage of excess PV generation
A one metric ton weight on a 30 meter tall tower has a potential energy of 81 watt hours. I’d stick with batteries. The only places gravity storage works are where you have “free” height and huge amounts of free weight. That is, an existing lake at a good elevation for pumped storage. But on that note, it’s cheaper to buy and opportunistically fill a 1,000 gallon plastic storage tank than to buy the batteries needed to fill that storage tank on demand. Store the final product if you can. Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
[RE-wrenches] Intermittent
Hello Wrenches Here’s a classic problem for you. I installed an array of 11 Trina 380s on a ground mount, commissioned January 6 of this year. It worked fine for a while, but in the last week it has had an intermittent power problem. For example, this morning it was putting out zero watts at the inverter. I measured voltage at the disconnect at the array and got zero volts. I checked all the connections and wires and it all seemed solid. I had to leave so I couldn’t start isolating modules. I came back this afternoon and it was producing an appropriate amount of power for the light conditions. What’s the most obvious thing that could be going on? Some kind of micro crack and thermal expansion? Thanks, Hilton Dier III Renewable Energy Design Missisquoi River Hydro LLC ___ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
[RE-wrenches] IRS Audit
I had to look into this once and it really isn't any more complex than the statement. It's not about UL listing or whatever. Does it generate electricity from solar? Is it installed on or connected to an occupied residential home? The restriction is that it has to be just the system itself. If you have to replace the roofing material before installing, that roofing material is not considered "qualified." Conduit in a trench to a ground mount is qualified. Landscaping work to clean up after the trench is not. Hilton Dier Missisquoi River Hydro LLC Renewable Energy Design ___ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
[RE-wrenches] Portable systems
I've got someone asking me about a portable system. It really doesn't have to be that portable. They just need a couple of kWh to back up their pellet stove for a day. There are loads of battery-and-inverter-in-a-box systems out there, but I have no idea about the quality of components. Does anybody have experience with any of these systems and have any recommendations? Many thanks, Hilton Dier Missisquoi River Hydro LLC Renewable Energy Design ___ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
[RE-wrenches] The Stupid Outlet
With the talk about heating battery banks on the list lately I thought I'd share fix that I did last year. I have an off grid customer with a place used by an extended family. They were engaging in the usual mission creep. Maybe mission leap would be a better expression. Anyway, they were plugging in stupid things and periodically crashing the battery bank. I got a 6x6 metal box and put a standard 120V outlet in it, as well as a 40A* rated solid state relay. There's a heavy duty extension cord coming out of it and a control wire for the relay. I stuck it on the wall next to the Outback panel, wired it into an aux relay, and plugged it into the outlet on the side of the panel. I programmed the system to only turn on the relay/outlet when the battery voltage was 56.8V or higher. The battery pack would have to be charged and the sun shining to turn on the outlet. I (privately) call it the Stupid Outlet. I suppose, to be kind, I should call it the Ignorant Outlet, but I've been over this with them a few times. I told the clients that if they had any question at all about whether they should plug something in, plug it into the gray box. For example, they have a dehumidifier they want to use in the basement. About 450 watts. Into the Stupid Outlet it goes. It only runs when the sun is shining. It reduces my stress level. I suppose you could tell clients it is the Sunshine Outlet. *40A because I want it to be 2x oversized for absolute durability. -- Hilton Dier III Missisquoi River Hydro Renewable Energy Design ___ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
