Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
Hi Larry, no amp hour meter installed yet as the customer is penny pinching. We're trying to solve the problem first and I've been out there twice, once to do general diagnostics and check all connections, try to load test the batteries, and so on; the second time I 'dropped in' to try a different load test on the batteries to see if I could replicate the problem and to resolve some other problems with a Whisper controller that had given up the ghost when disconnected re-connected to the batteries (all precautions taken). It's a seven hour round trip and with time spent on the job makes for an expensive service call. I only charged for one call and I have to go back at least once more. So customer wanted to save some money on the installation of the TriMetric until the spring... sorry for the long winded reply. I know, it's false economy. So I'm thinking I'll just put the meter in and tell them to pay me when they feel like it. It'll help solve the problem and get some of the Wrenches off my back ... ;-) Ron Young On 2011-11-13, at 8:26 AM, la...@starlightsolar.com la...@starlightsolar.com wrote: Ron, I stick by my evaluation as seen here: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/msg10694.html The #1 reason for my opinion is that you can NOT drive up voltage on a healthy bank that size in just 5 minutes. It is impossible with a 2500 watt generator. Here is the pertinent part from my post: You mentioned that the the battery drops to 24.5 in the early AM without any heavy loads on. For the 4KS25 battery this equates to about 800AH at the 72 hour rate. Then you said that the customer ran a 2500 watt generator for 5 minutes and drove the voltage up to 29 volts. Here's the Ah-Ha moment: That is EXACTLY the behavior of a heavily sulfated battery bank. A fast rise in voltage indicates sulfation. It is impossible for that tiny generator, or any charge source they own for that matter, to replace the hundreds of AH it would take to drive a healthy battery up to the absorb voltage of 29 volts. The bank is about 45,000 watt hours (72h rate). There would have to be over 20,000 Wh removed to be at that voltage. How many Wh's are replaced in 5 minutes by a 2500 watt genny? I'm sure you are getting the picture. Also, why have you not installed a battery monitor yet? It will give you eyes into the battery and spare countless hours of time diagnosing the problem. Larry Original Message Subject: Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation From: Ron Young solarea...@solareagle.com Date: Sat, November 12, 2011 9:57 pm To: RE-wrenches re-wrenches@lists.re-wrenches.org Folks, this one really has me puzzled. The client has done regular two hour EQ's, at least once a month. When did a site visit and I topped up the electrolyte (they'd been starving the batteries for water but always just above the plates) the problem seemed to go away. They were satisfied that the problem was solved but I wasn't and I told them what I had been hearing from this group - essentially that the batteries needed a deep EQ, discharge, recharge and EQ again two or three times to scrub the sulphates. They declined until just a few days ago when they said the rapid voltage drop was back. Here's a quote: We had another rapid voltage loss this morning ---it was 25.2 when we got up and it dropped rapidly to 22.8. We turned on the generator and charged the batteries until our display showed 30.2 for awhile with the generator running. We turned off the generator and the voltage settled at about 26.4. We turned off all loads and wind and solar. At 9.15 our batteries were at 26.4 At 9:16 we turned on an 8W light bulb, a1600W hair dryer, and a 1.5HP (120V 5.75A) shop vac The display showed a load of 1.9kw At 9:40 the inverter shut down---display showed batteries at 18.4 By 9.47 the display showed the batteries at 25.2the solar and wind were still shut down. We turned everything back on (a light, Sunfrost RF16, phone) and all seems to be normal. They agreed to do the EQ process but only have a 3kw generator so we started with 8 hours with the EQ voltage set for 32v (24v system). They completed that yesterday and here's what resulted: Before starting EQ the batteries were at 25.8, hydrometer reading 1283 with temp. correction Began EQ32.6 v Buying 1.5 kw Hour 1 32.4 v 1283 with temp. correction Buying 1.4 Hour 2 32.4 v 1285 with temp. correction Buying 1.5 Hour 3 32.2 v
Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
Hi Daryl. I've got other KS25's in hybrid systems (wind gen solar) that seem to do fine over the last several years. The Ouback 3524 has an 85 amp charger. There was no problem getting to 32 v and holding it for eight hours. This has been done twice now. Larry and others attribute the ability to get to 32v to a sulphated battery condition and I'm thinking that a healthy battery could get to 32v as well, especially one that's been regularly EQ'd... am I wrong? I'm listening to every opinion here and trying to sort it out but I think John may be on the right track with an intermittent failure of one cell. I just can't seem to find it. Ron Young On 2011-11-13, at 3:51 AM, penobscotso...@midmaine.com wrote: Ron, What comes to mind for me is that Surrette 5000 series batteries like to have a regular charge of C10. KS25 cells are rated for 1350 ah, creating a need for a somewhat regularly occurring charge of 135 amps. I do believe the batteries are not ever getting that, except for very rare occasions. We have seen this before in undersized systems. Is the bulk charge set to 29.6? I would try a couple more eq's over the next month to loosen likely sulfation. Get it up to as close to 32 volts as possible and taper the charge down, then eq at that voltage for four or five hours, even more if the client will do it. That would be how we would deal with this. It does seem ultimately to be sulfation that is the problem. Daryl DeJoy NABCEP Certified PV installer Penobscot Solar Design Folks, this one really has me puzzled. The client has done regular two hour EQ's, at least once a month. When did a site visit and I topped up the electrolyte (they'd been starving the batteries for water but always just above the plates) the problem seemed to go away. They were satisfied that the problem was solved but I wasn't and I told them what I had been hearing from this group - essentially that the batteries needed a deep EQ, discharge, recharge and EQ again two or three times to scrub the sulphates. They declined until just a few days ago when they said the rapid voltage drop was back. Here's a quote: We had another rapid voltage loss this morning ---it was 25.2 when we got up and it dropped rapidly to 22.8. We turned on the generator and charged the batteries until our display showed 30.2 for awhile with the generator running. We turned off the generator and the voltage settled at about 26.4. We turned off all loads and wind and solar. At 9.15 our batteries were at 26.4 At 9:16 we turned on an 8W light bulb, a1600W hair dryer, and a 1.5HP (120V 5.75A) shop vac The display showed a load of 1.9kw At 9:40 the inverter shut down---display showed batteries at 18.4 By 9.47 the display showed the batteries at 25.2the solar and wind were still shut down. We turned everything back on (a light, Sunfrost RF16, phone) and all seems to be normal. They agreed to do the EQ process but only have a 3kw generator so we started with 8 hours with the EQ voltage set for 32v (24v system). They completed that yesterday and here's what resulted: Before starting EQ the batteries were at 25.8, hydrometer reading 1283 with temp. correction Began EQ32.6 v Buying 1.5 kw Hour 1 32.4 v 1283 with temp. correction Buying 1.4 Hour 2 32.4 v 1285 with temp. correction Buying 1.5 Hour 3 32.2 v Buying 1.7 Hour 4 32.2 v 1290 with temp correctionBuying 1.8 HOur 5 32.0 v 1290 with temp correctionBuying 1.8 Hour 6 32.0 v Buying 1.9 Hour 7 31.8 v 1292 with temp correctonBuying 1.9 Hour 8 complete---turned off Gen and turned on loads ---Batteries dropped to 25.4 within 30 minutes and stayed there until this morning---fridge was running, telephone, internet, wool carding machine, lights. This morning hydrometer reading was at 1290. Then today I just got this email: Just experienced another rapid voltage drop. As soon as the voltage hits 24.8 the voltage drops like a rock if we don't have any input (no solar or wind). This is not what I expected after a lengthy EQ. I'm getting them to do another one tomorrow after a discharge cycle and charge but I'm really beginning to think we have something else going on here, something electrical, not
Re: [RE-wrenches] combiner bus bar for Sunny Tower DC input?
You will need a fuse for each inverter for the same reason you would need a fuse for 4 PV strings. Jim Duncan North Texas Renewable Energy -Original Message- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org]On Behalf Of Glenn Burt Sent: Tuesday, November 15, 2011 7:57 PM To: 'RE-wrenches' Subject: Re: [RE-wrenches] combiner bus bar for Sunny Tower DC input? Are you sure you need to split them? IIR, there are only a pair of conductors going from each SB into the tower. They must be combined on the SMA side of the touch-safe fuse holders in some way. We opted to run all our source circuits from array through 6 external discos then into the ST instead of combining them - the distance in our case was around 150'. -Glenn From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Kirk Herander Sent: Tuesday, November 15, 2011 8:10 PM To: 'RE-wrenches' Subject: Re: [RE-wrenches] combiner bus bar for Sunny Tower DC input? But I don't believe the Sunny Tower internally has single conductor lugs leading to the respective SB it's wired to. The DC tower input/output to each respective inverter is effectively a combiner box which combines all fused inputs to a single positive prewired to the respective SB inverter. I have already combined the strings in an external box and need to uncombine them through the individual fused strings in the SunnyTower. Kirk Herander VT Solar, LLC dba Vermont Solar Engineering NABCEPTM Certified installer Charter Member NYSERDA-eligible Installer VT RE Incentive Program Partner From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Brian Teitelbaum Sent: Monday, November 14, 2011 8:28 PM To: RE-wrenches Subject: Re: [RE-wrenches] combiner bus bar for Sunny Tower DC input? Hi Kirk, The Sunny Boy inverters also have a pair of lugs for a single conductor pair coming in from the array. They are meant to be used if you have an external combiner. No bus bars as you describe are needed. Brian Teitelbaum AEE Solar From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Kirk Herander Sent: Monday, November 14, 2011 2:57 PM To: RE-wrenches Subject: [RE-wrenches] combiner bus bar for Sunny Tower DC input? Hello, The Sunny Tower has four individual fuse holders on the DC input of each inverter. I am combining the array output for each inverter in a combiner box before the tower, so there is only a single positive, negative, and gnd going to each inverter's DC input. I want to fan this input out to each of the four dc fuses via a combiner bus with a single lug and prongs which fit directly into each fuseholders' input, ala the Outback combiner bus. Is there something similar made for the SunnyTower dc input? I have not been able to talk to SMA yet about this. Thanks. Kirk Herander VT Solar, LLC dba Vermont Solar Engineering NABCEPTM Certified installer Charter Member NYSERDA-eligible Installer VT RE Incentive Program Partner attachment: North Texas Renewable Energy Inc.vcf___ 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] Sharp triangles
Does Sharp still make those quasi-triangular mods? Thanks, marco ___ 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] intermittent battery problem; ...Battery Sulfation
We are only on your back until you to do the advisable thing: Sell them a battery capacity monitor. It is a hard fact that NO off grid, battery based power system should be without a battery capacity monitor. They are cheap (only $150!) and not an option. Apparently, it is also hard learned fact. ;-) Larry Crutcher Starlight Solar Power Systems On Nov 16, 2011, at 12:20 AM, Ron Young wrote: Hi Larry, no amp hour meter installed yet as the customer is penny pinching. We're trying to solve the problem first and I've been out there twice, once to do general diagnostics and check all connections, try to load test the batteries, and so on; the second time I 'dropped in' to try a different load test on the batteries to see if I could replicate the problem and to resolve some other problems with a Whisper controller that had given up the ghost when disconnected re-connected to the batteries (all precautions taken). It's a seven hour round trip and with time spent on the job makes for an expensive service call. I only charged for one call and I have to go back at least once more. So customer wanted to save some money on the installation of the TriMetric until the spring... sorry for the long winded reply. I know, it's false economy. So I'm thinking I'll just put the meter in and tell them to pay me when they feel like it. It'll help solve the problem and get some of the Wrenches off my back ... ;-) Ron Young On 2011-11-13, at 8:26 AM, la...@starlightsolar.com la...@starlightsolar.com wrote: Ron, I stick by my evaluation as seen here: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/msg10694.html The #1 reason for my opinion is that you can NOT drive up voltage on a healthy bank that size in just 5 minutes. It is impossible with a 2500 watt generator. Here is the pertinent part from my post: You mentioned that the the battery drops to 24.5 in the early AM without any heavy loads on. For the 4KS25 battery this equates to about 800AH at the 72 hour rate. Then you said that the customer ran a 2500 watt generator for 5 minutes and drove the voltage up to 29 volts. Here's the Ah-Ha moment: That is EXACTLY the behavior of a heavily sulfated battery bank. A fast rise in voltage indicates sulfation. It is impossible for that tiny generator, or any charge source they own for that matter, to replace the hundreds of AH it would take to drive a healthy battery up to the absorb voltage of 29 volts. The bank is about 45,000 watt hours (72h rate). There would have to be over 20,000 Wh removed to be at that voltage. How many Wh's are replaced in 5 minutes by a 2500 watt genny? I'm sure you are getting the picture. Also, why have you not installed a battery monitor yet? It will give you eyes into the battery and spare countless hours of time diagnosing the problem. Larry Original Message Subject: Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation From: Ron Young solarea...@solareagle.com Date: Sat, November 12, 2011 9:57 pm To: RE-wrenches re-wrenches@lists.re-wrenches.org Folks, this one really has me puzzled. The client has done regular two hour EQ's, at least once a month. When did a site visit and I topped up the electrolyte (they'd been starving the batteries for water but always just above the plates) the problem seemed to go away. They were satisfied that the problem was solved but I wasn't and I told them what I had been hearing from this group - essentially that the batteries needed a deep EQ, discharge, recharge and EQ again two or three times to scrub the sulphates. They declined until just a few days ago when they said the rapid voltage drop was back. Here's a quote: We had another rapid voltage loss this morning ---it was 25.2 when we got up and it dropped rapidly to 22.8. We turned on the generator and charged the batteries until our display showed 30.2 for awhile with the generator running. We turned off the generator and the voltage settled at about 26.4. We turned off all loads and wind and solar. At 9.15 our batteries were at 26.4 At 9:16 we turned on an 8W light bulb, a1600W hair dryer, and a 1.5HP (120V 5.75A) shop vac The display showed a load of 1.9kw At 9:40 the inverter shut down---display showed batteries at 18.4 By 9.47 the display showed the batteries at 25.2the solar and wind were still shut down. We turned everything back on (a light, Sunfrost RF16, phone) and all seems to be normal. They agreed to do the EQ process but only have a 3kw generator so we started with 8 hours with the EQ voltage set for 32v (24v system). They completed that yesterday and here's what resulted: Before starting EQ the batteries were at 25.8, hydrometer reading 1283 with temp. correction Began EQ32.6 v
Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
Ron, you have misquoted me so yes you are wrong. It is not about getting to 32 volts. Go read it again. On Nov 16, 2011, at 12:20 AM, Ron Young wrote: Hi Daryl. I've got other KS25's in hybrid systems (wind gen solar) that seem to do fine over the last several years. The Ouback 3524 has an 85 amp charger. There was no problem getting to 32 v and holding it for eight hours. This has been done twice now. Larry and others attribute the ability to get to 32v to a sulphated battery condition and I'm thinking that a healthy battery could get to 32v as well, especially one that's been regularly EQ'd... am I wrong? I'm listening to every opinion here and trying to sort it out but I think John may be on the right track with an intermittent failure of one cell. I just can't seem to find it. Ron Young On 2011-11-13, at 3:51 AM, penobscotso...@midmaine.com wrote: Ron, What comes to mind for me is that Surrette 5000 series batteries like to have a regular charge of C10. KS25 cells are rated for 1350 ah, creating a need for a somewhat regularly occurring charge of 135 amps. I do believe the batteries are not ever getting that, except for very rare occasions. We have seen this before in undersized systems. Is the bulk charge set to 29.6? I would try a couple more eq's over the next month to loosen likely sulfation. Get it up to as close to 32 volts as possible and taper the charge down, then eq at that voltage for four or five hours, even more if the client will do it. That would be how we would deal with this. It does seem ultimately to be sulfation that is the problem. Daryl DeJoy NABCEP Certified PV installer Penobscot Solar Design Folks, this one really has me puzzled. The client has done regular two hour EQ's, at least once a month. When did a site visit and I topped up the electrolyte (they'd been starving the batteries for water but always just above the plates) the problem seemed to go away. They were satisfied that the problem was solved but I wasn't and I told them what I had been hearing from this group - essentially that the batteries needed a deep EQ, discharge, recharge and EQ again two or three times to scrub the sulphates. They declined until just a few days ago when they said the rapid voltage drop was back. Here's a quote: We had another rapid voltage loss this morning ---it was 25.2 when we got up and it dropped rapidly to 22.8. We turned on the generator and charged the batteries until our display showed 30.2 for awhile with the generator running. We turned off the generator and the voltage settled at about 26.4. We turned off all loads and wind and solar. At 9.15 our batteries were at 26.4 At 9:16 we turned on an 8W light bulb, a1600W hair dryer, and a 1.5HP (120V 5.75A) shop vac The display showed a load of 1.9kw At 9:40 the inverter shut down---display showed batteries at 18.4 By 9.47 the display showed the batteries at 25.2the solar and wind were still shut down. We turned everything back on (a light, Sunfrost RF16, phone) and all seems to be normal. They agreed to do the EQ process but only have a 3kw generator so we started with 8 hours with the EQ voltage set for 32v (24v system). They completed that yesterday and here's what resulted: Before starting EQ the batteries were at 25.8, hydrometer reading 1283 with temp. correction Began EQ32.6 v Buying 1.5 kw Hour 1 32.4 v 1283 with temp. correction Buying 1.4 Hour 2 32.4 v 1285 with temp. correction Buying 1.5 Hour 3 32.2 v Buying 1.7 Hour 4 32.2 v 1290 with temp correctionBuying 1.8 HOur 5 32.0 v 1290 with temp correctionBuying 1.8 Hour 6 32.0 v Buying 1.9 Hour 7 31.8 v 1292 with temp correctonBuying 1.9 Hour 8 complete---turned off Gen and turned on loads ---Batteries dropped to 25.4 within 30 minutes and stayed there until this morning---fridge was running, telephone, internet, wool carding machine, lights. This morning hydrometer reading was at 1290. Then today I just got this email: Just experienced another rapid voltage drop. As soon as the voltage hits 24.8 the voltage drops like a rock if we don't have any input (no solar or wind). This is not what I expected after a lengthy EQ. I'm getting them to
[RE-wrenches] 90 degree wire bends
Some electricians have great fun in making 90 degree wire bends to try and make their enclosure wiring look so purdy. Given the importance of maintaining wiring radiuses, this can't be a good idea, can it? Is the issue greater resistance when the wire is bent at a straight 90 degrees (or more)? Thanks, marco ___ 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] Sizing 3 phase OCPD - main
Hi wrenches, I have a question about sizing the main OCP breaker for a panel combining the output of several true three-phase output inverters. To be precise - 10 of the Refusol 20kW, which connect to 480V/277 Y with a max output of 24.1 amps, each inverter has a 3 pole breaker, line a, b, c and a neutral, which doesn’t apparently carry any current. Recommended interconnection breaker is 35 Amps. Ok fine, but what should the main breaker and main panel busbar rating be? What I’m not sure about is if this is the right equation for the main breaker in a panel combining all ten inverter outputs: 10 x 24.1A x √3 x 1.25 = 521.8 A or is this the right equation: 10 x 24.1A x 1.25 = 301.25 A The busbar rating should be easy, once I get the main disco OCPD figured out. Main OCPD + (10 x 35) ≤ 120% busbar rating Thanks for the help! Rebekah Hren___ 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] Sizing 3 phase OCPD - main
Rebekah, If you knew only the power and voltage, then you would use the root of 3 to determine the amps. But since you know the amps, you don't need to use the root. The second equation would be the correct one. Mark Frye Berkeley Solar Electric Systems 303 Redbud Way Nevada City, CA 95959 (530) 401-8024 http://www.berkeleysolar.com/ www.berkeleysolar.com _ From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Rebekah Hren Sent: Wednesday, November 16, 2011 9:36 AM To: RE-wrenches@lists.re-wrenches.org Subject: [RE-wrenches] Sizing 3 phase OCPD - main Hi wrenches, I have a question about sizing the main OCP breaker for a panel combining the output of several true three-phase output inverters. To be precise - 10 of the Refusol 20kW, which connect to 480V/277 Y with a max output of 24.1 amps, each inverter has a 3 pole breaker, line a, b, c and a neutral, which doesn't apparently carry any current. Recommended interconnection breaker is 35 Amps. Ok fine, but what should the main breaker and main panel busbar rating be? What I'm not sure about is if this is the right equation for the main breaker in a panel combining all ten inverter outputs: 10 x 24.1A x v3 x 1.25 = 521.8 A or is this the right equation: 10 x 24.1A x 1.25 = 301.25 A The busbar rating should be easy, once I get the main disco OCPD figured out. Main OCPD + (10 x 35) ? 120% busbar rating Thanks for the help! Rebekah Hren ___ 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] 90 degree wire bends
It seems that if the strands were stretched and therefore thinned, that that would increase resistance, some. I think more importantly, the insulation bunchs up and cracks, and is definitely compromised. Also with strain hardening of copper, I'm sure some strands could break internally with a tight enough bend. I've heard at least for bare ground wires that lightning will jump off to the case at tight bends, but I've never actually seen that. Aside from all that, is there actually an increased impedance from a tight bend (like in plumbing)? I don't know. I've had to stop more than one journeyman from violating 300.34. I just tell them the bends should look like the long sweeps in conduit relative to the diameter of the wire: also purdy. Aloha, Ray On 11/16/2011 10:35 AM, Marco Mangelsdorf wrote: Some electricians have great fun in making 90 degree wire bends to try and make their enclosure wiring look so purdy. Given the importance of maintaining wiring radiuses, this can't be a good idea, can it? Is the issue greater resistance when the wire is bent at a straight 90 degrees (or more)? Thanks, marco ___ 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 ___ 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] SW4048 AC Coupling
Fellow Wrenches, I would welcome some feedback on this one: I may be adopting an eleven year old, Y2K, grid tie with battery back-up system. It consists of 12 - Astro-Power 120 modules, installed in 2000, 12 - Evergreen EC-110 modules installed in 2004, only one MX60, which controls BOTH sub-arrays, one SW4048 in SELL mode through a dedicated load sub-panel. Existing, seven year old battery is shot (8-Trojan L-16). Initial bank of unknown batteries was replaced after only four years. Recent long, nearby, utility outages have the client requesting a proposal to include a new back-up generator and to restore the system selling to the grid. Client may decide go straight grid tie to eliminate the batteries. They have found the maintenance to be a hassle. My thoughts so far: 1)To take advantage of most of the existing hardware, I wonder if it makes sense to try to improve the system efficiency by relegating the SW to a manual back-up mode only, where, say, by means of a timer controlling grid availability through AC1, it would only charge a smaller battery bank, once a week. The bank would be a single string of either, sealed gel units or T-105s with the new Trojan watering system. 2) Provide new grid-tie inverter/s to handle the net metering. 3) Provide a way to AC couple the new inverter/s to the SW in the event of an outage. 4) Provide a new Honda 3000 inverter type generator connected to AC2 in the SW. 5)Provide a way to lockout the grid tie inverter/s when the generator is operating. I think a few of you are still running your original SW inverters in grid tie mode. Any upgrades? Am I going off the deep end here? Dick Ratico Solarwind Electric Bradford, VT ___ 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] intermittent battery problem; ...Battery Sulfation
You're correct Larry, my apologies. Been burning the candle at both ends. Thanks for your input. On 2011-11-16, at 9:04 AM, Larry Crutcher, Starlight Solar Power Systems wrote: Ron, you have misquoted me so yes you are wrong. It is not about getting to 32 volts. Go read it again. On Nov 16, 2011, at 12:20 AM, Ron Young wrote: Hi Daryl. I've got other KS25's in hybrid systems (wind gen solar) that seem to do fine over the last several years. The Ouback 3524 has an 85 amp charger. There was no problem getting to 32 v and holding it for eight hours. This has been done twice now. Larry and others attribute the ability to get to 32v to a sulphated battery condition and I'm thinking that a healthy battery could get to 32v as well, especially one that's been regularly EQ'd... am I wrong? I'm listening to every opinion here and trying to sort it out but I think John may be on the right track with an intermittent failure of one cell. I just can't seem to find it. Ron Young On 2011-11-13, at 3:51 AM, penobscotso...@midmaine.com wrote: Ron, What comes to mind for me is that Surrette 5000 series batteries like to have a regular charge of C10. KS25 cells are rated for 1350 ah, creating a need for a somewhat regularly occurring charge of 135 amps. I do believe the batteries are not ever getting that, except for very rare occasions. We have seen this before in undersized systems. Is the bulk charge set to 29.6? I would try a couple more eq's over the next month to loosen likely sulfation. Get it up to as close to 32 volts as possible and taper the charge down, then eq at that voltage for four or five hours, even more if the client will do it. That would be how we would deal with this. It does seem ultimately to be sulfation that is the problem. Daryl DeJoy NABCEP Certified PV installer Penobscot Solar Design Folks, this one really has me puzzled. The client has done regular two hour EQ's, at least once a month. When did a site visit and I topped up the electrolyte (they'd been starving the batteries for water but always just above the plates) the problem seemed to go away. They were satisfied that the problem was solved but I wasn't and I told them what I had been hearing from this group - essentially that the batteries needed a deep EQ, discharge, recharge and EQ again two or three times to scrub the sulphates. They declined until just a few days ago when they said the rapid voltage drop was back. Here's a quote: We had another rapid voltage loss this morning ---it was 25.2 when we got up and it dropped rapidly to 22.8. We turned on the generator and charged the batteries until our display showed 30.2 for awhile with the generator running. We turned off the generator and the voltage settled at about 26.4. We turned off all loads and wind and solar. At 9.15 our batteries were at 26.4 At 9:16 we turned on an 8W light bulb, a1600W hair dryer, and a 1.5HP (120V 5.75A) shop vac The display showed a load of 1.9kw At 9:40 the inverter shut down---display showed batteries at 18.4 By 9.47 the display showed the batteries at 25.2the solar and wind were still shut down. We turned everything back on (a light, Sunfrost RF16, phone) and all seems to be normal. They agreed to do the EQ process but only have a 3kw generator so we started with 8 hours with the EQ voltage set for 32v (24v system). They completed that yesterday and here's what resulted: Before starting EQ the batteries were at 25.8, hydrometer reading 1283 with temp. correction Began EQ32.6 v Buying 1.5 kw Hour 1 32.4 v 1283 with temp. correction Buying 1.4 Hour 2 32.4 v 1285 with temp. correction Buying 1.5 Hour 3 32.2 v Buying 1.7 Hour 4 32.2 v 1290 with temp correctionBuying 1.8 HOur 5 32.0 v 1290 with temp correctionBuying 1.8 Hour 6 32.0 v Buying 1.9 Hour 7 31.8 v 1292 with temp correctonBuying 1.9 Hour 8 complete---turned off Gen and turned on loads ---Batteries dropped to 25.4 within 30 minutes and stayed there until this morning---fridge was running, telephone, internet, wool carding machine, lights. This morning hydrometer reading was at 1290. Then today I just got this email: Just experienced another rapid voltage drop. As
Re: [RE-wrenches] intermittent battery problem; ...Battery Sulfation
Ron, This reply a little late since I have been off line a few days. I mentioned in a similar thread last year that I had an off grid home client I designed and installed in Idaho back in 1998 that had a Kohler 8.5 kw generator, a Trace 4024 inverter, two separate solar arrays and Outback charge controllers, and 16 Trojan L-16 batteries. This system worked flawlessly for 7 years and only required the generator a few hours per month, then it was time to change the batteries. I replaced the Trojans with the same size battery made by Surrette and everything went to crap. They had to run the generator hours and hours to get them past an 80% charge and we had lots of problems with overloading the generator even though we did not make any program changes and used the same generator. The generator was replaced 2 years later but this system never worked like it did before the battery replacement. When researching all this at that time I had talked with Surrette, Trojan, and anyone else that might help and this is what I found out. Of course there are just my opinions based on these conversations, but it is my understanding that Surrette is a much longer life battery with much less water loss when comparing apples and apples, and I was told this was due to a different lead composition that Surrette uses than any other battery manufacturer. However, this difference requires a much longer absorption/taper off charge process or you will never get it past 80% charged. This of course is almost impossible to achieve with a generator or undersized solar array, and you really need a grid connection to fully charge these things. No doubt these would be great in some standby grid connected system but I no longer use them in off grid. This was also at a time when battery manufacturers were just discovering solar so maybe battery designs have changed. Again, I think Surrette is a good company and makes a great battery, but just not sure you can fully recharge them with a mid-sized generator. I also do not like using parallel battery layouts as its hard to keep one string from pulling down the other strings when there is a low performance cell so you might do a cell by cell check. Good Luck, Jeff Yago DTI Solar Inc. --- This is not what I expected after a lengthy EQ. I'm getting them to do another one tomorrow after a discharge cycle and charge but I'm really beginning to think we have something else going on here, something electrical, not chemical. The rapid voltage drop is puzzling. To review, it's an Outback 3524 on an Epanel, Whisper 100 controller, 6 4KS 25 Surrette batteries in 24v configuration - 4.5 years old, .7kw solar. I know the charging end is undersized but they have been compensating with the generator and they get lots of wind in the fall, winter, spring. ___ 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] Sizing 3 phase OCPD - main
Hi rebecca, I assume the inverters are all true 3 phase, to check 20 kW/480/1.73 = 24 amps this is what you expect on each leg. You have 10 of these therefore 240 amps on each leg. Solar is continous so you need x1.25 this is of course 301 amps you need to select a 301 breaker, but I think NEC 240.6 will allow a 300 amp. ((sorry I do not have my code book and I am on the road)) Good Luck Darryl From: Mark Frye ma...@berkeleysolar.com To: 'Rebekah Hren' bekahh...@yahoo.com; 'RE-wrenches' re-wrenches@lists.re-wrenches.org Sent: Wednesday, November 16, 2011 11:43 AM Subject: Re: [RE-wrenches] Sizing 3 phase OCPD - main Rebekah, If you knew only the power and voltage, then you would use the root of 3 to determine the amps. But since you know the amps, you don't need to use the root. The second equation would be the correct one. Mark Frye Berkeley Solar Electric Systems 303 Redbud Way Nevada City, CA 95959 (530) 401-8024 www.berkeleysolar.com From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Rebekah Hren Sent: Wednesday, November 16, 2011 9:36 AM To: RE-wrenches@lists.re-wrenches.org Subject: [RE-wrenches] Sizing 3 phase OCPD - main Hi wrenches, I have a question about sizing the main OCP breaker for a panel combining the output of several true three-phase output inverters. To be precise - 10 of the Refusol 20kW, which connect to 480V/277 Y with a max output of 24.1 amps, each inverter has a 3 pole breaker, line a, b, c and a neutral, which doesn’t apparently carry any current. Recommended interconnection breaker is 35 Amps. Ok fine, but what should the main breaker and main panel busbar rating be? What I’m not sure about is if this is the right equation for the main breaker in a panel combining all ten inverter outputs: 10 x 24.1A x √3 x 1.25 = 521.8 A or is this the right equation: 10 x 24.1A x 1.25 = 301.25 A The busbar rating should be easy, once I get the main disco OCPD figured out. Main OCPD + (10 x 35) ≤ 120% busbar rating Thanks for the help! Rebekah Hren ___ 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___ 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] 3-phase wire run considerations
Hi Folks, In several months we will be installing a 100kW ground mounted PV system for one of our commercial customers. I'm in the planning stage and am looking at the wire runs. The site requires a 700' underground wire run between the 480V service and the single central inverter located at the array (a PVP100kW unit). I have two related questions: 1: Given the significant cost of the AC cabling for this situation, what is the most appropriate number to use for current in running voltage drop calcs? The wiring is going to be significantly oversized to achieve a ~1% VD at this length. I could use the max rated output current of the inverter (120A), but that seems like it might be overly conservative. Opinions? 2: It looks like the most cost effective and manageable solution for this run will involve several paralleled sets of cables. How important are the considerations of careful cable bundling? ie: putting several conductors per phase willy nilly in a trench vs having separate triplexed bundles. Thanks in advance for your thoughts. Luke Christy NABCEP Certified PV Installer™: Certification #031409-25 (Luke Christy) NABCEP Certified Solar Thermal Installer™: Certification #ST032611-03 CoSEIA Certified PV Installer (Luke Christy) Solar Gain Services, LLC Monte Vista, CO. sgsrenewab...@gmail.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: [RE-wrenches] 90 degree wire bends
I have seen the lightening damage at tight bends, but in my electrical career of 60+ years I have not seen any other problems. Darryl From: Ray Walters r...@solarray.com To: RE-wrenches re-wrenches@lists.re-wrenches.org Sent: Wednesday, November 16, 2011 12:11 PM Subject: Re: [RE-wrenches] 90 degree wire bends It seems that if the strands were stretched and therefore thinned, that that would increase resistance, some. I think more importantly, the insulation bunchs up and cracks, and is definitely compromised. Also with strain hardening of copper, I'm sure some strands could break internally with a tight enough bend. I've heard at least for bare ground wires that lightning will jump off to the case at tight bends, but I've never actually seen that. Aside from all that, is there actually an increased impedance from a tight bend (like in plumbing)? I don't know. I've had to stop more than one journeyman from violating 300.34. I just tell them the bends should look like the long sweeps in conduit relative to the diameter of the wire: also purdy. Aloha, Ray On 11/16/2011 10:35 AM, Marco Mangelsdorf wrote: Some electricians have great fun in making 90 degree wire bends to try and make their enclosure wiring look so purdy. Given the importance of maintaining wiring radiuses, this can’t be a good idea, can it? Is the issue greater resistance when the wire is bent at a straight 90 degrees (or more)? Thanks, marco ___ 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 ___ 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___ 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] 3-phase wire run considerations
y seem to be on top of the situation. I would use the MPPT wattage of the array for my source wattage. devide by 480 volts and 1.73 for three phase and you have the current per leg.to do your voltage drop calcs from. IO have not always been carefull to keep similar phases apart, but you will probibly buy your direct burrial in the form of triplex so lay them like you buy them. Of course do not runn through metal holes unless balanced currents. Also any time you make a short run, KEEP the length the same. DT From: Luke Christy sgsrenewab...@gmail.com To: re-wrenches@lists.re-wrenches.org Sent: Wednesday, November 16, 2011 9:51 PM Subject: [RE-wrenches] 3-phase wire run considerations Hi Folks, In several months we will be installing a 100kW ground mounted PV system for one of our commercial customers. I'm in the planning stage and am looking at the wire runs. The site requires a 700' underground wire run between the 480V service and the single central inverter located at the array (a PVP100kW unit). I have two related questions: 1: Given the significant cost of the AC cabling for this situation, what is the most appropriate number to use for current in running voltage drop calcs? The wiring is going to be significantly oversized to achieve a ~1% VD at this length. I could use the max rated output current of the inverter (120A), but that seems like it might be overly conservative. Opinions? 2: It looks like the most cost effective and manageable solution for this run will involve several paralleled sets of cables. How important are the considerations of careful cable bundling? ie: putting several conductors per phase willy nilly in a trench vs having separate triplexed bundles. Thanks in advance for your thoughts. Luke Christy NABCEP Certified PV Installer™: Certification #031409-25 (Luke Christy) NABCEP Certified Solar Thermal Installer™: Certification #ST032611-03 CoSEIA Certified PV Installer (Luke Christy) Solar Gain Services, LLC Monte Vista, CO. sgsrenewab...@gmail.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___ 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] 3-phase wire run considerations
Luke: Maximum inverter output will occur rarely. Most of the time the inverter(s) will be running at lesser output amps. One approach is to size wiring for a certain percentage of the average operating amps. What is the average operating amps? One way I have found to calculate this is use PV Watts and invoke the tool that gives a data set of hour by hour results. This includes night time hours. Delete all values with a zero output and average the rest. I found a daily bell curve that is about 50% of full power. Your results may vary. Good luck, William Miller At 07:51 PM 11/16/2011, you wrote: 1: Given the significant cost of the AC cabling for this situation, what is the most appropriate number to use for current in running voltage drop calcs? The wiring is going to be significantly oversized to achieve a ~1% VD at this length. I could use the max rated output current of the inverter (120A), but that seems like it might be overly conservative. Opinions? ___ 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] intermittent battery problem; ...Battery Sulfation
I digress but... the best battery for grid tie with backup is not lead antimony, but lead calcuum. Surrette makes these too and they use next to no water and have a much longer warrantied life. Todd On Wednesday, November 16, 2011 6:52pm, Jeff Yago jry...@dtisolar.com said: No doubt these would be great in some standby grid connected system but I no longer use them in off grid. This was also at a time when battery manufacturers were just discovering solar so maybe battery designs have changed. Sent from Finest Planet WebMail. ___ 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
