Re: [RE-wrenches] PV Assist White Paper
This is an excellent paper that I would love to share with potential customers in it's final form. I have one suggestion - there might be a caveat in your load start example where you have a single large load that comes on occasionally and for a short period. For example, if there is a piece of machinery that comes on for 15 minutes and draws 2.5kw on it's own, but only runs once per day (a well pump for example), it may be advantageous to set the load start amps a little higher even though it exceeds the 5% rule. This may be more desirable than extending the load start delay. I've run into this when lifting daily water requirements to an elevated tank. I didn't feel it was necessary to start the generator every day in this case. What I would take from this paper as a buyer is that every system is very different, which is exactly what we want to point out. The other thing is that changing load conditions require recalculation and recalibration. One thing I like to point people to is Norther Arizona Wind Sun's Battery faq (http://www.solar-electric.com/deep-cycle-battery-faq.html). If they are not willing to read and understand this, or don't want a pricey maintenance contract, they may not be cut out for battery backup living. Jason Szumlanski Fafco Solar On Mon, Aug 19, 2013 at 8:19 PM, William Miller will...@millersolar.comwrote: ** Friends: I wrote a draft white paper to discuss the issues relevant to PV Assist systems. If you are up for along read, please feel free. If you have suggestions, I welcome them. This idea is new to me so I am learning as I go. Also, I could not easily past the chart so I included a link to it. Also, the table did not quite line u, but I think you canfigure it out. Thanks, William Miller *GENERATOR / BATTERY WITH PV ASSIST* August 19, 2013 * DRAFT, PRINCIPLES DISCUSSED ARE UNDER RESEARCH * * Introduction: *Whenever we design an Off-grid Alternative Energy systems, we usually design the system so that non-fossil battery charging sources (solar, wind, hydro) provide a majority of the energy for battery charging. Sometimes we come across systems that have loads that are so large that it is not practical to rely solely on non-fossil sources. A large generator will be needed to run on a daily basis. We call these systems Generator / Battery Systems with PV Assist, or PV Assist for short. We use the term PV to describe all RE charging sources since PV is most common in our area. We have found that battery charging in PV Assist systems using traditional settings may cause premature failure in battery arrays for reasons described below. We want everyone to enjoy the longest battery life possible so we have developed some alternative settings for battery charging that will hopefully achieve longer battery life. It has always been the goal of solar technicians to minimize generator run time. In retrospect, this may not be the best idea in PV Assist systems. The consequence may be reduced battery life. Batteries wear out when they are cycled. A cycle is defined as a discharge and charge. Normally, an off-grid system will charge batteries during the day and discharge them at night, resulting in one cycle per day. In the case of a PV Assist, the batteries may cycle multiple times per day. Your battery bank is rated for a finite number of cycles. If they cycle 4 times per day, they wear out 4 times faster than if they cycled once per day. In an attempt to preserve the longevity of a battery bank in a PV Assist system, we are experimenting with alternative generator auto start and inverter / charge battery charge settings. In general, we suggest that if batteries are going to be cycled multiple times per day, that they be cycled less deeply. In other words, do not discharged the batteries to as low a voltage as one would normally. In order to achieve this goal, the generator will run more frequently than in a traditional hybrid off-grid system. In these systems it is already a given that generator run time will occur every day, even multiple times per day. We are essentially embracing generator run time to preserve battery life. We are trading off greater wear-and-tear on the generator for less wear-and-tear on the batteries. The decision to do this belongs with the system owner. * Battery DOD versus life span: * See figure 1 below that compares the depth of discharge (DOD) of a battery to battery life. Note that the maximum expected cycles is 4,000. If you cycle 4 times per day at this DOD, expect 1,000 days of life, or three years. If you cycle to 80% you can expect 1000 cycles, or 250 days. This is a very short life span and this scenario needs to be avoided. The sweet spot is to be determined for each unique situation, but for discussion we are assuming we want 3000 cycles, or about 2 years. This is not long for a battery bank, but keep in mind this design assumes we have
Re: [RE-wrenches] PV Assist
Eric: It sounds like you are developing a sound knowledge base on your own. I am sure you have lots to contribute. It is nice to see your posts on some interesting subjects. William _ From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of SunHarvest Sent: Saturday, August 17, 2013 2:20 PM To: RE-wrenches Subject: Re: [RE-wrenches] PV Assist As you're aware William, being my mentor, I can't give you advice on your designs...none-the-less I figured I'd throw my hat in the ring of our talkabout (verbal walkabout)... I've seen plenty of wealthy homeowners turn to solar initially for the savings and end up acquiring an affinity for saving energy which, as I've seen, can lead to an awareness on the importance of ecological preservation. Some have even put aside their more conservative sociopolitical ideologies and recalled their inherent desire to connect with their environment, a.k.a. become more hippied-out man. We run up against this concept with every single solar panel we sell. Where is it manufactured? Not at the local, organic, free-range, fair-trade solar farm that's for sure. How much embodied energy and chemical by-product comes with each module (let's not talk about batteries)? Way, way, way too much. But for now, as this is the time of transition, solar is the lesser of two evils. The underlying truth is that in order to establish a sustainable existence, at a bare minimum, we must not consume more resources than we produce. This is hardly possible given any modern lifestyle, even the most eco-friendly. Each and every one of us that are not living entirely off the land and putting back all the nutrients that we consume; despite our best intentions, recycling our plastic bottles, shopping at farmer's markets, driving electric cars, are slowly destroying our planet. So what do we do? We may not be able to save the earth but we can wake as many sleeping zombie-consumers as possible and see where that gets us. The way I see it, our good work is far from perfect but it's a modest means to a greater end and everyone must get on board, fast; even the gluttons; especially the gluttons. As it's been said, we're the pioneers. We're the messengers, the alarm clocks, and the catalysts of this paradigm shift. Energy technology is changing fast, in both the renewable and conventional sectors and we're the ones, selling solar to everything that breathes and has a pocketbook, that are helping renewables to beat coal, oil, natty gas, nuclear; and If we don't do it, who will? In order for the green revolution to contend and win we need to build bridges between the tree-huggers and the oil-mongers and that is accomplished not by creating an eco-elite but through persistent diplomacy... ...Hey, come back here with my soapbox!... ___ 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] PV Assist
Well said, WIlliam. Just because we are installing solar does not mean all our intent is green I provide solar systems and generators, I am a provider of engineering solutions. I do not judge clients based on their green qualifications, just on their ability to pay me. We are in business to provide engineering solutions. By the way, William, have you looked at the SMA Fuel Saver solutions? I am proposing that technology for an industrial customer whose plant runs entirely off generators. On Fri, Aug 16, 2013 at 8:56 PM, William Miller will...@millersolar.comwrote: ** Friends: I am a bit surprised at the responses I have gotten on this thread. I appreciate the technical advice and I don't mind the polite philosophical discussion like the one below. However, I received one reply, fortunately off-line, that was not very polite, to say the least. I have been advised to abandon the clients that don't fit someone's criteria of green living. I don't think this is appropriate advice, especially if the adviser does not know what the whole story is. For example, one of the aforementioned clients was sold a bill of goods by a now defunct local installer. He retired, bought the property, moved in with a generator and then waited way too long for the scam artist to build a system that would power everything with the rays of the sun. Tens of thousands of dollars later the client fired the scammer and asked me to help as best I could. He is on a fixed income, he lives with extended family, the daughter has severe health problems, the son in law is out of work, etc.. My client is in a tight situation, with no good choices. Yes, I could tell the guy f*** you, you don't meet my standards. But I am not that kind of person. I am trying to help the customer get by as best he can by working as a team. This, my friends, is the professional and humane thing to do, and I make no apologies. Have a nice weekend everyone. William Miller 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. Wm -Original Message- From: re-wrenches-boun...@lists.re-wrenches.org [ mailto:re-wrenches-boun...@lists.re-wrenches.orgre-wrenches-boun...@lists.re-wrenches.org ] On Behalf Of penobscotso...@midmaine.com Sent: Friday, August 16, 2013 3:22 PM To: RE-wrenches Subject: Re: [RE-wrenches] PV Assist Honestly, William, in these type of cases I usually walk away from the job if the customer isn't willing to reduce where possible. There is no such thing as a completely fool proof off grid PV system. Like a good lawyer, the best way to have a stellar record is to know which cases to takejust one man's opinion of course, but we get approached for many systems like this, particularly in the Caribbean and I have learned that there is such a thing as a good solar customer and also a bad solar customer. Daryl ___ 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 -- Chris Mason President, Comet Systems Ltd www.cometenergysystems.com Cell: 264.235.5670 Skype: netconcepts ___ 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] PV Assist
Chris, I'd be interested in that Fuel Saver solution as well. From what I can tell, it interacts only with larger SMA inverter models. Keep me in the loop on what you find out about it. Thanks On Sat, Aug 17, 2013 at 8:22 AM, Chris Mason cometenergysyst...@gmail.comwrote: Well said, WIlliam. Just because we are installing solar does not mean all our intent is green I provide solar systems and generators, I am a provider of engineering solutions. I do not judge clients based on their green qualifications, just on their ability to pay me. We are in business to provide engineering solutions. By the way, William, have you looked at the SMA Fuel Saver solutions? I am proposing that technology for an industrial customer whose plant runs entirely off generators. On Fri, Aug 16, 2013 at 8:56 PM, William Miller will...@millersolar.comwrote: ** Friends: I am a bit surprised at the responses I have gotten on this thread. I appreciate the technical advice and I don't mind the polite philosophical discussion like the one below. However, I received one reply, fortunately off-line, that was not very polite, to say the least. I have been advised to abandon the clients that don't fit someone's criteria of green living. I don't think this is appropriate advice, especially if the adviser does not know what the whole story is. For example, one of the aforementioned clients was sold a bill of goods by a now defunct local installer. He retired, bought the property, moved in with a generator and then waited way too long for the scam artist to build a system that would power everything with the rays of the sun. Tens of thousands of dollars later the client fired the scammer and asked me to help as best I could. He is on a fixed income, he lives with extended family, the daughter has severe health problems, the son in law is out of work, etc.. My client is in a tight situation, with no good choices. Yes, I could tell the guy f*** you, you don't meet my standards. But I am not that kind of person. I am trying to help the customer get by as best he can by working as a team. This, my friends, is the professional and humane thing to do, and I make no apologies. Have a nice weekend everyone. William Miller 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. Wm -Original Message- From: re-wrenches-boun...@lists.re-wrenches.org [ mailto:re-wrenches-boun...@lists.re-wrenches.orgre-wrenches-boun...@lists.re-wrenches.org ] On Behalf Of penobscotso...@midmaine.com Sent: Friday, August 16, 2013 3:22 PM To: RE-wrenches Subject: Re: [RE-wrenches] PV Assist Honestly, William, in these type of cases I usually walk away from the job if the customer isn't willing to reduce where possible. There is no such thing as a completely fool proof off grid PV system. Like a good lawyer, the best way to have a stellar record is to know which cases to takejust one man's opinion of course, but we get approached for many systems like this, particularly in the Caribbean and I have learned that there is such a thing as a good solar customer and also a bad solar customer. Daryl ___ 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 -- Chris Mason President, Comet Systems Ltd www.cometenergysystems.com Cell: 264.235.5670 Skype: netconcepts ___ 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 -- Mac Lewis * Yo solo sé que no sé nada. -Sócrates * ___ 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] PV Assist / battery watering systems
Hi Ray, This battery watering system is solid. http://www.aquapro.net/ Since moving over to this brand, that came highly recommended to me, I have had zero issues. 1,000's of caps for 5-6 years now. Kevin -Original Message- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org]On Behalf Of Ray Walters Sent: August 16, 2013 5:28 PM To: RE-wrenches Subject: Re: [RE-wrenches] PV Assist Hi Kevin; Which watering system did you find that worked? We've been through a bunch that were worse than no watering system at all. R.Ray Walters CTO, Solarray, Inc Nabcep Certified PV Installer, Licensed Master Electrician Solar Design Engineer 303 505-8760 On 8/16/2013 5:38 PM, Kevin Pegg wrote: For either config, a single point battery watering system is ideal, as uses a lot of water. Can be automated so the filling system pump runs for xx seconds at the start of each absorb cycle. I've had to go through a lot of junk few dry cells to find one system that does this reliably. Kevin Pegg EA Energy Alternatives Ltd. British Columbia, Canada. ___ 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] PV Assist - customer management
Funny reminds me of the old days, I seem to recall a lot of years back, on this same discussion site, a similar exchange. It seems that one installer was looking for advice concerning an overly demanding customer with unreasonable expectations for a PV systems performance. The customer was the Dept. of Defense. Opposing points-of-view questioned why any Wrench in their right mind would waste perfectly good, and expensive, PV on someone whose goal was world domination and death to all who opposed them. I'll sell 'em PV because I'm in the business of selling PV was the response. Other debates have sprung from Wrenches complaining that potential customers have two SUVs parked in front of a 6500 sf home. These people clearly don't get it! Why should I waste PV on them? The answer is always the same. Because it's what we do. McMansion owners and the DOD are now believers and established customers. Now there is no one that wouldn't agree that the growing exodus from our decaying, congested and polluted urban metromess will not continue to increase. It's no different now than years ago. Sell them all the PV they are willing to pay for but do it with unabashed honesty. And when they are neck deep in challenges from their lifestyle decision, they will always remember that you warned them that it would be like this. And they will respect you for it if they have an ounce of integrity. This new generation of get-out-of-town with their all-electric lifestyle may be our next market segment to deal with. If you don't want their business then some other PV installer will. If the job's done right the first time it benefits us all. If not we all take one step back. Our industry competition includes the coal, natural gas and electric utility cartel. They and a lot of politicians, stand shoulder to shoulder in opposition to individuals generating their own power. You had better take every customer you can get and make a believer out of them because the competition is doing everything they can to put up hurdles to PV growth. And because ours is one of those industries that trains-your-competition it's important that we train them to high standards. It's not easy being a pioneer. Jim Duncan From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Hilton Dier III Sent: Saturday, August 17, 2013 9:13 AM To: RE-wrenches@lists.re-wrenches.org Subject: [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: [RE-wrenches] PV Assist - customer management
It's been all downhill for us hippies since Jerry Rubin went to work on Wall Street. Sent from my Verizon Wireless BlackBerry -Original Message- From: Solarguy nt...@1scom.net Sender: re-wrenches-boun...@lists.re-wrenches.orgDate: Sat, 17 Aug 2013 10:41:38 To: 'RE-wrenches're-wrenches@lists.re-wrenches.org Reply-To: RE-wrenches re-wrenches@lists.re-wrenches.org Subject: Re: [RE-wrenches] PV Assist - customer management ___ 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 ___ 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] PV Assist - customer management
Jim. Like my dear friend Bob Maynard once told me, The pioneers get the arrows. The settlers get the land. Bob-O On Aug 17, 2013, at 8:41 AM, Solarguy wrote: Funny reminds me of the old days, I seem to recall a lot of years back, on this same discussion site, a similar exchange. It seems that one installer was looking for advice concerning an overly demanding customer with unreasonable expectations for a PV systems performance. The customer was the Dept. of Defense. Opposing points-of-view questioned why any Wrench in their right mind would waste perfectly good, and expensive, PV on someone whose goal was world domination and death to all who opposed them. I’ll sell ‘em PV because I’m in the business of selling PV was the response. Other debates have sprung from Wrenches complaining that potential customers have two SUVs parked in front of a 6500 sf home. These people clearly don’t get it! Why should I waste PV on them? The answer is always the same. Because it’s what we do. McMansion owners and the DOD are now believers and established customers. Now there is no one that wouldn’t agree that the growing exodus from our decaying, congested and polluted urban metromess will not continue to increase. It’s no different now than years ago. Sell them all the PV they are willing to pay for but do it with unabashed honesty. And when they are neck deep in challenges from their lifestyle decision, they will always remember that you warned them that it would be like this. And they will respect you for it if they have an ounce of integrity. This new generation of get-out-of-town with their all-electric lifestyle may be our next market segment to deal with. If you don’t want their business then some other PV installer will. If the job’s done right the first time it benefits us all. If not we all take one step back. Our industry competition includes the coal, natural gas and electric utility cartel. They and a lot of politicians, stand shoulder to shoulder in opposition to individuals generating their own power. You had better take every customer you can get and make a believer out of them because the competition is doing everything they can to put up hurdles to PV growth. And because ours is one of those industries that trains-your-competition it’s important that we train them to high standards. It’s not easy being a pioneer. Jim Duncan From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Hilton Dier III Sent: Saturday, August 17, 2013 9:13 AM To: RE-wrenches@lists.re-wrenches.org Subject: [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 ___ 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] PV Assist
William, I have a couple customers in a similar situation. The homes are Mexico and they need to operate mini split A/C for a few months. There is no space for increasing the PV array. Once the generator run time is balanced to maintain the batteries between 50% and 80% while also handling any heavy loads, the system can perform well daily. The downside is that this deficit charging will lead to early battery failure. The solution I use is to have a Full Charge Day bimonthly. The customer must operate the generator through the Bulk and Absorb charge and then start a short, high voltage equalization charge for about 2 hours followed by battery SG testing. This method is the best I could come up with and seems to be working well. During the other months, the PV system can keep up with consumption. I too am getting more large system requests. If space is not a problem, I install large PV arrays to minimize generator use. Larry On Aug 16, 2013, at 12:53 PM, William Miller will...@millersolar.com wrote: Friends: We have been receiving a flurry of requests for design of off-grid systems where the loads are enormous, relative to normal off-grid requirements. It is obvious that the size of PV and battery arrays to power these loads is beyond what is practical. We have dubbed these systems Generator/battery with PV assist, or PV assist for short. These systems will cycle batteries multiple times per day. It is my understanding that the extra battery cycels will shorten battery life. Since generator run is expected, we are willing to increase generator run time in order to prolong battery life. The parameters I suggest are an aggressive load start and a very high battery start parameter. This will prevent deep discharge of the battery bank. I know shallow discharge is not the norm, but I don't believe shallow cycling is a problem as long is it as at the top of the voltage window, i.e. the batteries achieve absorption at least once per day. We know a load start ciuld result in an abbreviated run time, curtailing absorption period, but we are assuming there will be a battery votage start at least once per day allowing full absorption. Has anyone else considered these issues, and what conclusions did you make I am looking forward to a spirited discussion as usual. I throuroughlyenjoy and beneift from them, even thought the advice is usually conflilcting. Thanks in advance. William Miller ___ 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 ___ 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] PV Assist
Hi William; One thing to consider is that you want to cycle the batteries at least 20% DOD. If you look at the cycle charts for regular Lead acid batteries, the total KWH you can get from a battery for its lifetime is fairly equal from around 20% DOD to 80% DOD. (basically you can get twice the cycles at half the discharge rate) However this nice linear relationship goes out at the ends (over 80% DOD, or less than 20% DOD) You just don't get your money's worth cycling deep cycle batteries at very shallow depths. Another consideration is that it is very inefficient to charge a battery completely with generator power. The last half of the absorption phase is at fairly low current for fairly long time periods. You should have the genny shut down when its efficiency gets low (might be less than 25% of rated capacity, depends on the generator) My basic design philosophy is to not cycle the bank more than 50%, but have the generator shut off once the total watts (charging + loads - PV ) drops below a certain threshold. Also having the generator kick in when loads exceed a certain discharge rate (say C20) is important too. If they discharge at higher rates, you won't have your design amp hours because of the Puekert's exponent. (basically: batteries have less capacity at high discharge rates) Last point, I don' think its reasonable to expect the system to reach full charge every day, I'd shoot for once a week, and save a bunch of fuel. Deep cycle batteries can sit at less than full charge for a couple of weeks before the lead sulfate starts crystallizing into a non-disolvable form. In this case, you want a balance of fuel and generator run time vs battery life. I have a large system like this that the batteries have already outlived the generator, so that's probably not exactly optimum. I've since starting using smaller battery banks, also because batteries have gone up in price. For these types of designs, I find software like PV Design Pro to be very useful. It can characterize the total % of energy from PV, as well as model an hourly basis of the system operation over an average weather year. You still have to ride herd on software simulations, as they can turn out some pretty stupid designs if you're not careful. R.Ray Walters CTO, Solarray, Inc Nabcep Certified PV Installer, Licensed Master Electrician Solar Design Engineer 303 505-8760 On 8/16/2013 11:53 AM, William Miller wrote: Friends: We have been receiving a flurry of requests for design of off-grid systems where the loads are enormous, relative to normal off-grid requirements. It is obvious that the size of PV and battery arrays to power these loads is beyond what is practical. We have dubbed these systems Generator/battery with PV assist, or PV assist for short. These systems will cycle batteries multiple times per day. It is my understanding that the extra battery cycels will shorten battery life. Since generator run is expected, we are willing to increase generator run time in order to prolong battery life. The parameters I suggest are an aggressive load start and a very high battery start parameter. This will prevent deep discharge of the battery bank. I know shallow discharge is not the norm, but I don't believe shallow cycling is a problem as long is it as at the top of the voltage window, i.e. the batteries achieve absorption at least once per day. We know a load start ciuld result in an abbreviated run time, curtailing absorption period, but we are assuming there will be a battery votage start at least once per day allowing full absorption. Has anyone else considered these issues, and what conclusions did you make I am looking forward to a spirited discussion as usual. I throuroughlyenjoy and beneift from them, even thought the advice is usually conflilcting. Thanks in advance. William Miller ___ 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 ___ 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] PV Assist
off-grid systems where the loads are enormous, i realize this is not popular now in these days of solar is so cheap, but i will not work for people who wont conserve or be efficient. as we all know, pv contains lots of embedded energy and to my thinking... having it power waste is simply greenwashing... so the race to the bottom will have to happen without my help. i start every job (on or off grid) with an energy audit. the result is radically lower consumption levels, more conscious customers, a smaller system (so less resource use and less economic investment). this yields a win-win for the customer and planet. with propane/wood powering the water and space heating loads (and sometimes refrigeration), line drying laundry... generally the maximum consumption i see is in the 5 to 6 kWh/day area. around here, with our seasonal precipitation it is nearly impossible to do off grid without generator use in the winter. here again, conservation helps as it reduces the overall load, battery cycling (and wear) and generator use. i realize you were asking about battery cycling, but with lower consumption profiles, this becomes less of an issue. thats my old school .02 todd On Friday, August 16, 2013 10:53am, William Miller will...@millersolar.com said: Friends: We have been receiving a flurry of requests for design of off-grid systems where the loads are enormous, relative to normal off-grid requirements. It is obvious that the size of PV and battery arrays to power these loads is beyond what is practical. We have dubbed these systems Generator/battery with PV assist, or PV assist for short. These systems will cycle batteries multiple times per day. It is my understanding that the extra battery cycels will shorten battery life. Since generator run is expected, we are willing to increase generator run time in order to prolong battery life. The parameters I suggest are an aggressive load start and a very high battery start parameter. This will prevent deep discharge of the battery bank. I know shallow discharge is not the norm, but I don't believe shallow cycling is a problem as long is it as at the top of the voltage window, i.e. the batteries achieve absorption at least once per day. We know a load start ciuld result in an abbreviated run time, curtailing absorption period, but we are assuming there will be a battery votage start at least once per day allowing full absorption. Has anyone else considered these issues, and what conclusions did you make I am looking forward to a spirited discussion as usual. I throuroughlyenjoy and beneift from them, even thought the advice is usually conflilcting. Thanks in advance. William Miller Sent from Finest Planet WebMail. ___ 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] PV Assist
Wrenches: Oh yeah, I forgot to mention: Todd, you can hold the lecture: I agree with you but the repetition is wasting energy. William On Aug 16, 2013, at 12:01 PM, toddc...@finestplanet.com wrote: off-grid systems where the loads are enormous, i realize this is not popular now in these days of solar is so cheap, but i will not work for people who wont conserve or be efficient. as we all know, pv contains lots of embedded energy and to my thinking... having it power waste is simply greenwashing... so the race to the bottom will have to happen without my help. i start every job (on or off grid) with an energy audit. the result is radically lower consumption levels, more conscious customers, a smaller system (so less resource use and less economic investment). this yields a win-win for the customer and planet. with propane/wood powering the water and space heating loads (and sometimes refrigeration), line drying laundry... generally the maximum consumption i see is in the 5 to 6 kWh/day area. around here, with our seasonal precipitation it is nearly impossible to do off grid without generator use in the winter. here again, conservation helps as it reduces the overall load, battery cycling (and wear) and generator use. i realize you were asking about battery cycling, but with lower consumption profiles, this becomes less of an issue. thats my old school .02 todd ___ 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] PV Assist
Jay: There are four systems in question. In three the loads are year round and one is summer only AC loads. The year round loaded systems have loads day and night. One is a highway maintenence station with at least 4 residences. One is a family compound with two homes with electric ranges, water heaters, AC units (I know its stupid, lord knows I've tried to convince them to change appliances.) One is an animal rescue operation with heater loads. One is a large home with 5 very small, very new, very sophisticated and frugal AC units I know it is silly to move these loads off-grid, but people do it and they will hire someone to work on the systems. It may as well be me, doing the best I can to use the resources as wisely as possible. William PS: It always happens like this: I get a call from a client with problems. Well, of course their expensive battery bank died and it died because of wasteful appliances. The prescription is a new, expensive battery bank and, at the same time, new, expensive, efficient appliances. They complain can't afford both and they have to have the batteries, so that is what they get. Repeat every two years. Sad Wm _ From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Jay Peltz Sent: Friday, August 16, 2013 12:22 PM To: RE-wrenches Subject: Re: [RE-wrenches] PV Assist Hi William I feel it's impossible to discuss without more specifics. For example if the extreme loads are only every ( just run the genny) so often vs seasonal ( maybe AC coupling makes more sense vs cycling a extremely expensive battery 4 x day), vs year round vs what is do able etc I would be curious to know what some of the parameters are, as I'm sure others as well Jay Peltz power. Sent from my iPhone On Aug 16, 2013, at 10:53 AM, William Miller will...@millersolar.com wrote: Friends: We have been receiving a flurry of requests for design of off-grid systems where the loads are enormous, relative to normal off-grid requirements. It is obvious that the size of PV and battery arrays to power these loads is beyond what is practical. We have dubbed these systems Generator/battery with PV assist, or PV assist for short. These systems will cycle batteries multiple times per day. It is my understanding that the extra battery cycels will shorten battery life. Since generator run is expected, we are willing to increase generator run time in order to prolong battery life. The parameters I suggest are an aggressive load start and a very high battery start parameter. This will prevent deep discharge of the battery bank. I know shallow discharge is not the norm, but I don't believe shallow cycling is a problem as long is it as at the top of the voltage window, i.e. the batteries achieve absorption at least once per day. We know a load start ciuld result in an abbreviated run time, curtailing absorption period, but we are assuming there will be a battery votage start at least once per day allowing full absorption. Has anyone else considered these issues, and what conclusions did you make I am looking forward to a spirited discussion as usual. I throuroughlyenjoy and beneift from them, even thought the advice is usually conflilcting. Thanks in advance. William Miller ___ 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 ___ 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] PV Assist
Not to hijack the thread, but I'd like to add that the inverter rating required for enormous loads can also be beyond practical limits. We are getting a flood of grid-tie with PV and battery backup requests for whole house coverage. The reason for the consumer demand is obvious here in hurricane-prone SW Florida, especially this time of year. The answer is usually to steer the customer into a critical load system, still with a sizable battery, and a very large PV array. Theoretically this could result in similar multiple discharge cycles per day if daytime loads are significant enough relative to the battery and the PV production is variable (think air conditioning). I'll watch this discussion with interest... Jason Szumlanski Fafco Solar On Fri, Aug 16, 2013 at 1:53 PM, William Miller will...@millersolar.comwrote: ** Friends: We have been receiving a flurry of requests for design of off-grid systems where the loads are enormous, relative to normal off-grid requirements. It is obvious that the size of PV and battery arrays to power these loads is beyond what is practical. We have dubbed these systems Generator/battery with PV assist, or PV assist for short. These systems will cycle batteries multiple times per day. It is my understanding that the extra battery cycels will shorten battery life. Since generator run is expected, we are willing to increase generator run time in order to prolong battery life. The parameters I suggest are an aggressive load start and a very high battery start parameter. This will prevent deep discharge of the battery bank. I know shallow discharge is not the norm, but I don't believe shallow cycling is a problem as long is it as at the top of the voltage window, i.e. the batteries achieve absorption at least once per day. We know a load start ciuld result in an abbreviated run time, curtailing absorption period, but we are assuming there will be a battery votage start at least once per day allowing full absorption. Has anyone else considered these issues, and what conclusions did you make I am looking forward to a spirited discussion as usual. I throuroughlyenjoy and beneift from them, even thought the advice is usually conflilcting. Thanks in advance. William Miller ___ 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 ___ 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] PV Assist
Hi William Thx helps a lot. I can only say how I do it. I'll give the client some options, including the change of appliances and usually the price difference makes the sale one way or the other. Funny reminds me of the old days, only with much smaller loads/$. Good luck Jay Sent from my iPhone On Aug 16, 2013, at 12:49 PM, William Miller will...@millersolar.com wrote: Jay: There are four systems in question. In three the loads are year round and one is summer only AC loads. The year round loaded systems have loads day and night. One is a highway maintenence station with at least 4 residences. One is a family compound with two homes with electric ranges, water heaters, AC units (I know its stupid, lord knows I've tried to convince them to change appliances.) One is an animal rescue operation with heater loads. One is a large home with 5 very small, very new, very sophisticated and frugal AC units I know it is silly to move these loads off-grid, but people do it and they will hire someone to work on the systems. It may as well be me, doing the best I can to use the resources as wisely as possible. William PS: It always happens like this: I get a call from a client with problems. Well, of course their expensive battery bank died and it died because of wasteful appliances. The prescription is a new, expensive battery bank and, at the same time, new, expensive, efficient appliances. They complain can't afford both and they have to have the batteries, so that is what they get. Repeat every two years. Sad Wm From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Jay Peltz Sent: Friday, August 16, 2013 12:22 PM To: RE-wrenches Subject: Re: [RE-wrenches] PV Assist Hi William I feel it's impossible to discuss without more specifics. For example if the extreme loads are only every ( just run the genny) so often vs seasonal ( maybe AC coupling makes more sense vs cycling a extremely expensive battery 4 x day), vs year round vs what is do able etc I would be curious to know what some of the parameters are, as I'm sure others as well Jay Peltz power. Sent from my iPhone On Aug 16, 2013, at 10:53 AM, William Miller will...@millersolar.com wrote: Friends: We have been receiving a flurry of requests for design of off-grid systems where the loads are enormous, relative to normal off-grid requirements. It is obvious that the size of PV and battery arrays to power these loads is beyond what is practical. We have dubbed these systems Generator/battery with PV assist, or PV assist for short. These systems will cycle batteries multiple times per day. It is my understanding that the extra battery cycels will shorten battery life. Since generator run is expected, we are willing to increase generator run time in order to prolong battery life. The parameters I suggest are an aggressive load start and a very high battery start parameter. This will prevent deep discharge of the battery bank. I know shallow discharge is not the norm, but I don't believe shallow cycling isa problem as long is it as at the top of the voltage window, i.e. the batteries achieve absorption at least once per day. We know a load start ciuld result in an abbreviated run time, curtailing absorption period, but we are assuming there will be a battery votage start at least once per day allowing full absorption. Has anyone else considered these issues, and what conclusions did you make I am looking forward to a spirited discussion as usual. I throuroughlyenjoy and beneift from them, even thought the advice is usually conflilcting. Thanks in advance. William Miller ___ 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 ___ 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 ___ 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
Re: [RE-wrenches] PV Assist
Hi William, In off grid applications, you want to have sufficient RE to keep up with load demand and only run the generator when RE cannot keep up. However, having too much RE is a waste because it will result in energy not harvested (if regulating), however, diversion controllers can allow the excess energy to be utilized (i.e. water heating). Running the gen up to the bulk level replaces approx 80% of capacity, and maximizes fuel consumption, allowing RE to get the batteries charged the last 20%. Automatic gen start capability with staggered start voltages allow you to target 50% discharge more accurately, and minimizes user interaction. Try to calculate the total daily kWhrs and match the demand with RE as closely as possible. Hope that helps, Rgds, _ Eric Bentsen | Schneider Electric | Solar Business | UNITED STATES | Technical Support Representative Phone: +(650) 351-8237 ext. 001# | Email: eric.bent...@schneider-electric.com | Site: www.schneider-electric.com/solar | Address: 250 South Vasco Rd., Livermore, CA 94551 *** Please consider the environment before printing this e-mail From: Jay Peltz j...@asis.com To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: 08/16/2013 02:01 PM Subject: Re: [RE-wrenches] PV Assist Sent by: re-wrenches-boun...@lists.re-wrenches.org Hi William Thx helps a lot. I can only say how I do it. I'll give the client some options, including the change of appliances and usually the price difference makes the sale one way or the other. Funny reminds me of the old days, only with much smaller loads/$. Good luck Jay Sent from my iPhone On Aug 16, 2013, at 12:49 PM, William Miller will...@millersolar.com wrote: Jay: There are four systems in question. In three the loads are year round and one is summer only AC loads. The year round loaded systems have loads day and night. One is a highway maintenence station with at least 4 residences. One is a family compound with two homes with electric ranges, water heaters, AC units (I know its stupid, lord knows I've tried to convince them to change appliances.) One is an animal rescue operation with heater loads. One is a large home with 5 very small, very new, very sophisticated and frugal AC units I know it is silly to move these loads off-grid, but people do it and they will hire someone to work on the systems. It may as well be me, doing the best I can to use the resources as wisely as possible. William PS: It always happens like this: I get a call from a client with problems. Well, of course their expensive battery bank died and it died because of wasteful appliances. The prescription is a new, expensive battery bank and, at the same time, new, expensive, efficient appliances. They complain can't afford both and they have to have the batteries, so that is what they get. Repeat every two years. Sad Wm From: re-wrenches-boun...@lists.re-wrenches.org [ mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Jay Peltz Sent: Friday, August 16, 2013 12:22 PM To: RE-wrenches Subject: Re: [RE-wrenches] PV Assist Hi William I feel it's impossible to discuss without more specifics. For example if the extreme loads are only every ( just run the genny) so often vs seasonal ( maybe AC coupling makes more sense vs cycling a extremely expensive battery 4 x day), vs year round vs what is do able etc I would be curious to know what some of the parameters are, as I'm sure others as well Jay Peltz power. Sent from my iPhone On Aug 16, 2013, at 10:53 AM, William Miller will...@millersolar.com wrote: Friends: We have been receiving a flurry of requests for design of off-grid systems where the loads are enormous, relative to normal off-grid requirements. It is obvious that the size of PV and battery arrays to power these loads is beyond what is practical. We have dubbed these systems Generator/battery with PV assist, or PV assist for short. These systems will cycle batteries multiple times per day. It is my understanding that the extra battery cycels will shorten battery life. Since generator run is expected, we are willing to increase generator run time in order to prolong battery life. The parameters I suggest are an aggressive load start and a very high battery start parameter. This will prevent deep discharge of the battery bank. I know shallow discharge is not the norm, but I don't believe shallow cycling is a problem as long is it as at the top of the voltage window, i.e. the batteries achieve absorption at least once per day. We know a load start ciuld result in an abbreviated run time, curtailing absorption period, but we are assuming there will be a battery votage start at least once per day allowing full absorption. Has anyone else considered these issues, and what conclusions did you make I am
Re: [RE-wrenches] PV Assist
Honestly, William, in these type of cases I usually walk away from the job if the customer isn't willing to reduce where possible. There is no such thing as a completely fool proof off grid PV system. Like a good lawyer, the best way to have a stellar record is to know which cases to takejust one man's opinion of course, but we get approached for many systems like this, particularly in the Caribbean and I have learned that there is such a thing as a good solar customer and also a bad solar customer. Daryl Hi William, In off grid applications, you want to have sufficient RE to keep up with load demand and only run the generator when RE cannot keep up. However, having too much RE is a waste because it will result in energy not harvested (if regulating), however, diversion controllers can allow the excess energy to be utilized (i.e. water heating). Running the gen up to the bulk level replaces approx 80% of capacity, and maximizes fuel consumption, allowing RE to get the batteries charged the last 20%. Automatic gen start capability with staggered start voltages allow you to target 50% discharge more accurately, and minimizes user interaction. Try to calculate the total daily kWhrs and match the demand with RE as closely as possible. Hope that helps, Rgds, _ Eric Bentsen | Schneider Electric | Solar Business | UNITED STATES | Technical Support Representative Phone: +(650) 351-8237 ext. 001# | Email: eric.bent...@schneider-electric.com | Site: www.schneider-electric.com/solar | Address: 250 South Vasco Rd., Livermore, CA 94551 *** Please consider the environment before printing this e-mail From: Jay Peltz j...@asis.com To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: 08/16/2013 02:01 PM Subject: Re: [RE-wrenches] PV Assist Sent by: re-wrenches-boun...@lists.re-wrenches.org Hi William Thx helps a lot. I can only say how I do it. I'll give the client some options, including the change of appliances and usually the price difference makes the sale one way or the other. Funny reminds me of the old days, only with much smaller loads/$. Good luck Jay Sent from my iPhone On Aug 16, 2013, at 12:49 PM, William Miller will...@millersolar.com wrote: Jay: There are four systems in question. In three the loads are year round and one is summer only AC loads. The year round loaded systems have loads day and night. One is a highway maintenence station with at least 4 residences. One is a family compound with two homes with electric ranges, water heaters, AC units (I know its stupid, lord knows I've tried to convince them to change appliances.) One is an animal rescue operation with heater loads. One is a large home with 5 very small, very new, very sophisticated and frugal AC units I know it is silly to move these loads off-grid, but people do it and they will hire someone to work on the systems. It may as well be me, doing the best I can to use the resources as wisely as possible. William PS: It always happens like this: I get a call from a client with problems. Well, of course their expensive battery bank died and it died because of wasteful appliances. The prescription is a new, expensive battery bank and, at the same time, new, expensive, efficient appliances. They complain can't afford both and they have to have the batteries, so that is what they get. Repeat every two years. Sad Wm From: re-wrenches-boun...@lists.re-wrenches.org [ mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Jay Peltz Sent: Friday, August 16, 2013 12:22 PM To: RE-wrenches Subject: Re: [RE-wrenches] PV Assist Hi William I feel it's impossible to discuss without more specifics. For example if the extreme loads are only every ( just run the genny) so often vs seasonal ( maybe AC coupling makes more sense vs cycling a extremely expensive battery 4 x day), vs year round vs what is do able etc I would be curious to know what some of the parameters are, as I'm sure others as well Jay Peltz power. Sent from my iPhone On Aug 16, 2013, at 10:53 AM, William Miller will...@millersolar.com wrote: Friends: We have been receiving a flurry of requests for design of off-grid systems where the loads are enormous, relative to normal off-grid requirements. It is obvious that the size of PV and battery arrays to power these loads is beyond what is practical. We have dubbed these systems Generator/battery with PV assist, or PV assist for short. These systems will cycle batteries multiple times per day. It is my understanding that the extra battery cycels will shorten battery life. Since generator run is expected, we are willing to increase generator run time in order to prolong battery life. The parameters I suggest are an aggressive load start and a very high battery start parameter
Re: [RE-wrenches] PV Assist
Hi William, I have done many systems in identical situations share your philosophy. Remote communities, work camps, highway maintenance compounds, etc... I have used two general philosophies on batteries for these systems. 1. Cheap batteries, ie L16's. Cycle them hard and realize they will be dead in 18-24 months. Keeping them cool is the biggest challenge with multiple cycles a day. Special attention to air flow in battery box helps. One site was able to config the room so the cold air intake for generator passes through the battery bank. Worked quite well. Also good for billable hrs to be replacing batteries constantly. 2. Higher quality flat plate 2V cells. Spend more now, shallow cycle them to around 60-70% DOD, have the gens set to kick in based on high continual AC demand (and shut down when that load abates). Generally speaking the threshold for that is 50% of the inverter rating but each site is unique. Some sites I have the gen may kick in up to 6x a day, not full cycles. Some sites with predictable peaks ie camps have timers to run gen from 6-8am then 5-7pm, to coincide with meals. Though I prefer based on AC demand. More flexible to adapt to the conditions ie if the site is shut down. For either config, a single point battery watering system is ideal, as uses a lot of water. Can be automated so the filling system pump runs for xx seconds at the start of each absorb cycle. I've had to go through a lot of junk few dry cells to find one system that does this reliably. Pricing wise over 10 years generally works out about the same, but cash flow is easier for cheap batteries, they just know they will have to spend a couple grand a year on batteries. They are saving 10's of thousands in diesel so still works out economically. Generally speaking, inverter capacity is 50% of generator. Several 50 kW diesel / 30 kW inverter / 100 kWh battery systems out there. A larger system we put in 16 months ago uses 100 kW diesels, 60 kW inverter, 400 kWh battery storage. I've worked with every inverter out there, and the SMA Sunny Island does the best job of properly charging batteries / and keeping generator runtime as low as possible. It can be set to short-charge batteries most of the time, ie shortened absorb stage and then every x cycles (defined) it will do a full charge. Find that is the very best balance between fuel use / battery life. Solar PV (or other renewables) are easy add ons. Every kWh from renewables is saving diesel. Hope that is useful. Kevin Pegg EA Energy Alternatives Ltd. British Columbia, Canada. -Original Message- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org]On Behalf Of William Miller Sent: August 16, 2013 12:49 PM To: 'RE-wrenches' Subject: Re: [RE-wrenches] PV Assist Jay: There are four systems in question. In three the loads are year round and one is summer only AC loads. The year round loaded systems have loads day and night. One is a highway maintenence station with at least 4 residences. One is a family compound with two homes with electric ranges, water heaters, AC units (I know its stupid, lord knows I've tried to convince them to change appliances.) One is an animal rescue operation with heater loads. One is a large home with 5 very small, very new, very sophisticated and frugal AC units I know it is silly to move these loads off-grid, but people do it and they will hire someone to work on the systems. It may as well be me, doing the best I can to use the resources as wisely as possible. William PS: It always happens like this: I get a call from a client with problems. Well, of course their expensive battery bank died and it died because of wasteful appliances. The prescription is a new, expensive battery bank and, at the same time, new, expensive, efficient appliances. They complain can't afford both and they have to have the batteries, so that is what they get. Repeat every two years. Sad Wm _ From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Jay Peltz Sent: Friday, August 16, 2013 12:22 PM To: RE-wrenches Subject: Re: [RE-wrenches] PV Assist Hi William I feel it's impossible to discuss without more specifics. For example if the extreme loads are only every ( just run the genny) so often vs seasonal ( maybe AC coupling makes more sense vs cycling a extremely expensive battery 4 x day), vs year round vs what is do able etc I would be curious to know what some of the parameters are, as I'm sure others as well Jay Peltz power. Sent from my iPhone On Aug 16, 2013, at 10:53 AM, William Miller will...@millersolar.com wrote: Friends: We have been receiving a flurry of requests for design of off-grid systems where the loads are enormous, relative to normal off-grid requirements. It is obvious that the size of PV
Re: [RE-wrenches] PV Assist
I find its also about the money. If they're expecting a $20k system to perform like a $100k one, then yes, move on. I agree with Daryl that you keep a good record by picking your clients. On the other hand, I have some fairly wealthy customers that don't want to reduce their loads, and are willing to pay for it both in PV and fuel. They've been excellent long term customers, so I'm not about to be as cavalier as others here and say walk away. I currently have a very energy minded customer that wants an electric stove and water heater, because she doesn't want to use any fossil fuels on site. If the customer wants a mega system and is willing to pay for it, why is it our business to judge them? R.Ray Walters CTO, Solarray, Inc Nabcep Certified PV Installer, Licensed Master Electrician Solar Design Engineer 303 505-8760 On 8/16/2013 4:22 PM, penobscotso...@midmaine.com wrote: Honestly, William, in these type of cases I usually walk away from the job if the customer isn't willing to reduce where possible. There is no such thing as a completely fool proof off grid PV system. Like a good lawyer, the best way to have a stellar record is to know which cases to takejust one man's opinion of course, but we get approached for many systems like this, particularly in the Caribbean and I have learned that there is such a thing as a good solar customer and also a bad solar customer. Daryl Hi William, In off grid applications, you want to have sufficient RE to keep up with load demand and only run the generator when RE cannot keep up. However, having too much RE is a waste because it will result in energy not harvested (if regulating), however, diversion controllers can allow the excess energy to be utilized (i.e. water heating). Running the gen up to the bulk level replaces approx 80% of capacity, and maximizes fuel consumption, allowing RE to get the batteries charged the last 20%. Automatic gen start capability with staggered start voltages allow you to target 50% discharge more accurately, and minimizes user interaction. Try to calculate the total daily kWhrs and match the demand with RE as closely as possible. Hope that helps, Rgds, _ Eric Bentsen | Schneider Electric | Solar Business | UNITED STATES | Technical Support Representative Phone: +(650) 351-8237 ext. 001# | Email: eric.bent...@schneider-electric.com | Site: www.schneider-electric.com/solar | Address: 250 South Vasco Rd., Livermore, CA 94551 *** Please consider the environment before printing this e-mail From: Jay Peltz j...@asis.com To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: 08/16/2013 02:01 PM Subject: Re: [RE-wrenches] PV Assist Sent by: re-wrenches-boun...@lists.re-wrenches.org Hi William Thx helps a lot. I can only say how I do it. I'll give the client some options, including the change of appliances and usually the price difference makes the sale one way or the other. Funny reminds me of the old days, only with much smaller loads/$. Good luck Jay Sent from my iPhone On Aug 16, 2013, at 12:49 PM, William Miller will...@millersolar.com wrote: Jay: There are four systems in question. In three the loads are year round and one is summer only AC loads. The year round loaded systems have loads day and night. One is a highway maintenence station with at least 4 residences. One is a family compound with two homes with electric ranges, water heaters, AC units (I know its stupid, lord knows I've tried to convince them to change appliances.) One is an animal rescue operation with heater loads. One is a large home with 5 very small, very new, very sophisticated and frugal AC units I know it is silly to move these loads off-grid, but people do it and they will hire someone to work on the systems. It may as well be me, doing the best I can to use the resources as wisely as possible. William PS: It always happens like this: I get a call from a client with problems. Well, of course their expensive battery bank died and it died because of wasteful appliances. The prescription is a new, expensive battery bank and, at the same time, new, expensive, efficient appliances. They complain can't afford both and they have to have the batteries, so that is what they get. Repeat every two years. Sad Wm From: re-wrenches-boun...@lists.re-wrenches.org [ mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Jay Peltz Sent: Friday, August 16, 2013 12:22 PM To: RE-wrenches Subject: Re: [RE-wrenches] PV Assist Hi William I feel it's impossible to discuss without more specifics. For example if the extreme loads are only every ( just run the genny) so often vs seasonal ( maybe AC coupling makes more sense vs cycling a extremely expensive battery 4 x day), vs year round vs what is do able etc I would be curious to know what some of the parameters are, as I'm sure others as well Jay
Re: [RE-wrenches] PV Assist
Hi Kevin; Which watering system did you find that worked? We've been through a bunch that were worse than no watering system at all. R.Ray Walters CTO, Solarray, Inc Nabcep Certified PV Installer, Licensed Master Electrician Solar Design Engineer 303 505-8760 On 8/16/2013 5:38 PM, Kevin Pegg wrote: For either config, a single point battery watering system is ideal, as uses a lot of water. Can be automated so the filling system pump runs for xx seconds at the start of each absorb cycle. I've had to go through a lot of junk few dry cells to find one system that does this reliably. Kevin Pegg EA Energy Alternatives Ltd. British Columbia, Canada. ___ 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] PV Assist
Friends: I am a bit surprised at the responses I have gotten on this thread. I appreciate the technical advice and I don't mind the polite philosophical discussion like the one below. However, I received one reply, fortunately off-line, that was not very polite, to say the least. I have been advised to abandon the clients that don't fit someone's criteria of green living. I don't think this is appropriate advice, especially if the adviser does not know what the whole story is. For example, one of the aforementioned clients was sold a bill of goods by a now defunct local installer. He retired, bought the property, moved in with a generator and then waited way too long for the scam artist to build a system that would power everything with the rays of the sun. Tens of thousands of dollars later the client fired the scammer and asked me to help as best I could. He is on a fixed income, he lives with extended family, the daughter has severe health problems, the son in law is out of work, etc.. My client is in a tight situation, with no good choices. Yes, I could tell the guy f*** you, you don't meet my standards. But I am not that kind of person. I am trying to help the customer get by as best he can by working as a team. This, my friends, is the professional and humane thing to do, and I make no apologies. Have a nice weekend everyone. William Miller 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. Wm -Original Message- From: re-wrenches-boun...@lists.re-wrenches.org [ mailto:re-wrenches-boun...@lists.re-wrenches.org mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of penobscotso...@midmaine.com Sent: Friday, August 16, 2013 3:22 PM To: RE-wrenches Subject: Re: [RE-wrenches] PV Assist Honestly, William, in these type of cases I usually walk away from the job if the customer isn't willing to reduce where possible. There is no such thing as a completely fool proof off grid PV system. Like a good lawyer, the best way to have a stellar record is to know which cases to takejust one man's opinion of course, but we get approached for many systems like this, particularly in the Caribbean and I have learned that there is such a thing as a good solar customer and also a bad solar customer. Daryl ___ 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] PV Assist
Folks, I've heard lots of good advice on this subject and as an old off-grid system designer, energy conservation has long been a field I take seriously. Generating power that you wouldn't otherwise need because you refuse to use the power wisely is just... Stupid. Stupid financially and stupid in just about any other category I can think of. To quote some redneck (but funny!) comic, You can't fix stupid. Like Todd, I've walked away from big money clients who just didn't -and wouldn't- get it. Heresy, I know, in a capitalistic economy. I blame my Hippie roots, but I make no apology for them. We am what we am. That said, I disagree with Eric that excess PV is a waste. At a module price of $6.00/Watt, you bet! At $1.50/W or less to the end user these days, not so much. I live off-grid and have for 40 years. I have what you might consider to be excess PV in the air. Ya know, if you don't take it to ridiculous lengths, there really ain't no such thing. During the high season, you will have electrons coming out your ears. As Jay and others have said, use them! Make hot water. Don't need hot water in the summer? Pump some water! Run an evaporative cooler. A freakin' water feature. Whatever. Be creative! Make your clients' lives funner and maybe make a few bucks at that. It's in the early Spring and Late Fall that excess PV really pays for itself. What's the real cost of an hour of generator time? I reckon it's somewhere between $4 and $8/ hour depending on fuel type, size, yada yada. The heavier the consumption, the more those sorta sunny or sorta cloudy PV days count. Even if you saved just 10% of genny time during those periods, do that math. Plus, for whatever that extra PV saves in genny time, the planet thanks you -and them. As a side bene, they don't have to listen to the damn thing. A feature, sell it! I also disagree with his suggestion to do things that minimizes user interaction I strive to MAXIMIZE user interaction! My experience shows me that the more the client relates to his/her system, the more reliable it is. That goes triple for generators. Did I just hear the generator start? Damn, I was gonna check the oil. Ah well, next time. Ya know? I totally understand that some folks will just not pay attention no matter how logical it is or despite your best efforts to explain that. But you have to try. It's an important part of our job and we need to do it. With passion. Ya gotta do what ya gotta do, but those uninvolved folks will be a thorn in your side for a long time. Sooner or later, there is a VERY good chance that they will cost you money. Believe it. Good Luck, bob-O On Aug 16, 2013, at 2:24 PM, eric.bent...@schneider-electric.com wrote: Hi William, In off grid applications, you want to have sufficient RE to keep up with load demand and only run the generator when RE cannot keep up. However, having too much RE is a waste because it will result in energy not harvested (if regulating), however, diversion controllers can allow the excess energy to be utilized (i.e. water heating). Running the gen up to the bulk level replaces approx 80% of capacity, and maximizes fuel consumption, allowing RE to get the batteries charged the last 20%. Automatic gen start capability with staggered start voltages allow you to target 50% discharge more accurately, and minimizes user interaction. Try to calculate the total daily kWhrs and match the demand with RE as closely as possible. Hope that helps, Rgds, _ Eric Bentsen | Schneider Electric | Solar Business | UNITED STATES | Technical Support Representative Phone: +(650) 351-8237 ext. 001# | Email: eric.bent...@schneider-electric.com | Site: www.schneider-electric.com/solar | Address: 250 South Vasco Rd., Livermore, CA 94551 Mail Attachment.jpeg *** Please consider the environment before printing this e-mail From: Jay Peltz j...@asis.com To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: 08/16/2013 02:01 PM Subject:Re: [RE-wrenches] PV Assist Sent by:re-wrenches-boun...@lists.re-wrenches.org Hi William Thx helps a lot. I can only say how I do it. I'll give the client some options, including the change of appliances and usually the price difference makes the sale one way or the other. Funny reminds me of the old days, only with much smaller loads/$. Good luck Jay Sent from my iPhone On Aug 16, 2013, at 12:49 PM, William Miller will...@millersolar.com wrote: Jay: There are four systems in question. In three the loads are year round and one is summer only AC loads. The year round loaded systems have loads day and night. One is a highway maintenence station with at least 4 residences. One is a family compound with two homes with electric ranges, water heaters, AC units (I know its stupid, lord knows I've tried to convince them
Re: [RE-wrenches] PV Assist
If the customer wants a mega system and is willing to pay for it, why is it our business to judge them? hi ray, is it judging them? or simply saying: i do this work because i believe in trying to make a more sustainable world... and i will not enable waste. i do not care what these people can afford... i care about what the earth can afford and we already have too many people consuming too much and teaching my clients to live energy and resource wisely benefits us all. maybe it is like bob-o said... my hippie roots, but we DO need to realize we are all in this together and there is no room for greedy sociopaths. mega systems take mega resources. there is no free lunch: this is a great article: [http://truth-out.org/news/item/15588-power-shift-away-from-green-illusions] http://truth-out.org/news/item/15588-power-shift-away-from-green-illusions my .o2 todd On Friday, August 16, 2013 5:26pm, Ray Walters r...@solarray.com said: I find its also about the money. If they're expecting a $20k system to perform like a $100k one, then yes, move on. I agree with Daryl that you keep a good record by picking your clients. On the other hand, I have some fairly wealthy customers that don't want to reduce their loads, and are willing to pay for it both in PV and fuel. They've been excellent long term customers, so I'm not about to be as cavalier as others here and say walk away. I currently have a very energy minded customer that wants an electric stove and water heater, because she doesn't want to use any fossil fuels on site. If the customer wants a mega system and is willing to pay for it, why is it our business to judge them? R.Ray Walters CTO, Solarray, Inc Nabcep Certified PV Installer, Licensed Master Electrician Solar Design Engineer 303 505-8760 On 8/16/2013 4:22 PM, penobscotso...@midmaine.com wrote: Honestly, William, in these type of cases I usually walk away from the job if the customer isn't willing to reduce where possible. There is no such thing as a completely fool proof off grid PV system. Like a good lawyer, the best way to have a stellar record is to know which cases to takejust one man's opinion of course, but we get approached for many systems like this, particularly in the Caribbean and I have learned that there is such a thing as a good solar customer and also a bad solar customer. Daryl Hi William, In off grid applications, you want to have sufficient RE to keep up with load demand and only run the generator when RE cannot keep up. However, having too much RE is a waste because it will result in energy not harvested (if regulating), however, diversion controllers can allow the excess energy to be utilized (i.e. water heating). Running the gen up to the bulk level replaces approx 80% of capacity, and maximizes fuel consumption, allowing RE to get the batteries charged the last 20%. Automatic gen start capability with staggered start voltages allow you to target 50% discharge more accurately, and minimizes user interaction. Try to calculate the total daily kWhrs and match the demand with RE as closely as possible. Hope that helps, Rgds, _ Eric Bentsen | Schneider Electric | Solar Business | UNITED STATES | Technical Support Representative Phone: +(650) 351-8237 ext. 001# | Email: eric.bent...@schneider-electric.com | Site: www.schneider-electric.com/solar | Address: 250 South Vasco Rd., Livermore, CA 94551 *** Please consider the environment before printing this e-mail From: Jay Peltz j...@asis.com To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: 08/16/2013 02:01 PM Subject: Re: [RE-wrenches] PV Assist Sent by: re-wrenches-boun...@lists.re-wrenches.org Hi William Thx helps a lot. I can only say how I do it. I'll give the client some options, including the change of appliances and usually the price difference makes the sale one way or the other. Funny reminds me of the old days, only with much smaller loads/$. Good luck Jay Sent from my iPhone On Aug 16, 2013, at 12:49 PM, William Miller will...@millersolar.com wrote: Jay: There are four systems in question. In three the loads are year round and one is summer only AC loads. The year round loaded systems have loads day and night. One is a highway maintenence station with at least 4 residences. One is a family compound with two homes with electric ranges, water heaters, AC units (I know its stupid, lord knows I've tried to convince them to change appliances.) One is an animal rescue operation with heater loads. One is a large home with 5 very small, very new, very sophisticated and frugal AC units I know it is silly to move these loads off-grid, but people do
Re: [RE-wrenches] PV Assist
so sorry list members, this was supposed to be off list. todd On Friday, August 16, 2013 8:51pm, toddc...@finestplanet.com said: If the customer wants a mega system and is willing to pay for it, why is it our business to judge them? hi ray, is it judging them? or simply saying: i do this work because i believe in trying to make a more sustainable world... and i will not enable waste. i do not care what these people can afford... i care about what the earth can afford and we already have too many people consuming too much and teaching my clients to live energy and resource wisely benefits us all. maybe it is like bob-o said... my hippie roots, but we DO need to realize we are all in this together and there is no room for greedy sociopaths. mega systems take mega resources. there is no free lunch: this is a great article: [http://truth-out.org/news/item/15588-power-shift-away-from-green-illusions] http://truth-out.org/news/item/15588-power-shift-away-from-green-illusions my .o2 todd On Friday, August 16, 2013 5:26pm, Ray Walters r...@solarray.com said: I find its also about the money. If they're expecting a $20k system to perform like a $100k one, then yes, move on. I agree with Daryl that you keep a good record by picking your clients. On the other hand, I have some fairly wealthy customers that don't want to reduce their loads, and are willing to pay for it both in PV and fuel. They've been excellent long term customers, so I'm not about to be as cavalier as others here and say walk away. I currently have a very energy minded customer that wants an electric stove and water heater, because she doesn't want to use any fossil fuels on site. If the customer wants a mega system and is willing to pay for it, why is it our business to judge them? R.Ray Walters CTO, Solarray, Inc Nabcep Certified PV Installer, Licensed Master Electrician Solar Design Engineer 303 505-8760 On 8/16/2013 4:22 PM, penobscotso...@midmaine.com wrote: Honestly, William, in these type of cases I usually walk away from the job if the customer isn't willing to reduce where possible. There is no such thing as a completely fool proof off grid PV system. Like a good lawyer, the best way to have a stellar record is to know which cases to takejust one man's opinion of course, but we get approached for many systems like this, particularly in the Caribbean and I have learned that there is such a thing as a good solar customer and also a bad solar customer. Daryl Hi William, In off grid applications, you want to have sufficient RE to keep up with load demand and only run the generator when RE cannot keep up. However, having too much RE is a waste because it will result in energy not harvested (if regulating), however, diversion controllers can allow the excess energy to be utilized (i.e. water heating). Running the gen up to the bulk level replaces approx 80% of capacity, and maximizes fuel consumption, allowing RE to get the batteries charged the last 20%. Automatic gen start capability with staggered start voltages allow you to target 50% discharge more accurately, and minimizes user interaction. Try to calculate the total daily kWhrs and match the demand with RE as closely as possible. Hope that helps, Rgds, _ Eric Bentsen | Schneider Electric | Solar Business | UNITED STATES | Technical Support Representative Phone: +(650) 351-8237 ext. 001# | Email: eric.bent...@schneider-electric.com | Site: www.schneider-electric.com/solar | Address: 250 South Vasco Rd., Livermore, CA 94551 *** Please consider the environment before printing this e-mail From: Jay Peltz j...@asis.com To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: 08/16/2013 02:01 PM Subject: Re: [RE-wrenches] PV Assist Sent by: re-wrenches-boun...@lists.re-wrenches.org Hi William Thx helps a lot. I can only say how I do it. I'll give the client some options, including the change of appliances and usually the price difference makes the sale one way or the other. Funny reminds me of the old days, only with much smaller loads/$. Good luck Jay Sent from my iPhone On Aug 16, 2013, at 12:49 PM, William Miller will...@millersolar.com wrote: Jay: There are four systems in question. In three the loads are year round and one is summer only AC loads. The year round loaded systems have loads day and night. One is a highway maintenence station with at least 4 residences. One is a family compound with two homes with electric ranges, water heaters, AC units (I know its stupid, lord knows I've tried to convince them to change appliances.) One is an animal rescue operation with heater loads. One is a large home with 5 very
Re: [RE-wrenches] PV Assist
Its alright Todd. I'm actually about as hippie as you get. I started in PV in the Peace Corp in Africa in the 80s doing water pumping systems. I built a solar adobe with my own hands from my own mud. Raised my kids there. I built electric vehicles when I realized that our energy habit extended beyond our dwelling. In the long run though, I quit taking my self so seriously. We're all doing what we can. Even the energy monster of the city is actually people living together more sustainably. Just to live off grid on your own piece of land isn't sustainable. How can 8 billion people all live like that? There isn't enough land, we have to live together. R.Ray Walters CTO, Solarray, Inc Nabcep Certified PV Installer, Licensed Master Electrician Solar Design Engineer 303 505-8760 On 8/16/2013 9:59 PM, toddc...@finestplanet.com wrote: so sorry list members, this was supposed to be off list. todd On Friday, August 16, 2013 8:51pm, toddc...@finestplanet.com said: If the customer wants a mega system and is willing to pay for it, why is it our business to judge them? hi ray, is it judging them? or simply saying: i do this work because i believe in trying to make a more sustainable world... and i will not enable waste. i do not care what these people can afford... i care about what the earth can afford and we already have too many people consuming too much and teaching my clients to live energy and resource wisely benefits us all. maybe it is like bob-o said... my hippie roots, but we DO need to realize we are all in this together and there is no room for greedy sociopaths. mega systems take mega resources. there is no free lunch: this is a great article: http://truth-out.org/news/item/15588-power-shift-away-from-green-illusions my .o2 todd On Friday, August 16, 2013 5:26pm, Ray Walters r...@solarray.com said: I find its also about the money. If they're expecting a $20k system to perform like a $100k one, then yes, move on. I agree with Daryl that you keep a good record by picking your clients. On the other hand, I have some fairly wealthy customers that don't want to reduce their loads, and are willing to pay for it both in PV and fuel. They've been excellent long term customers, so I'm not about to be as cavalier as others here and say walk away. I currently have a very energy minded customer that wants an electric stove and water heater, because she doesn't want to use any fossil fuels on site. If the customer wants a mega system and is willing to pay for it, why is it our business to judge them? R.Ray Walters CTO, Solarray, Inc Nabcep Certified PV Installer, Licensed Master Electrician Solar Design Engineer 303 505-8760 On 8/16/2013 4:22 PM, penobscotso...@midmaine.com wrote: Honestly, William, in these type of cases I usually walk away from the job if the customer isn't willing to reduce where possible. There is no such thing as a completely fool proof off grid PV system. Like a good lawyer, the best way to have a stellar record is to know which cases to takejust one man's opinion of course, but we get approached for many systems like this, particularly in the Caribbean and I have learned that there is such a thing as a good solar customer and also a bad solar customer. Daryl Hi William, In off grid applications, you want to have sufficient RE to keep up with load demand and only run the generator when RE cannot keep up. However, having too much RE is a waste because it will result in energy not harvested (if regulating), however, diversion controllers can allow the excess energy to be utilized (i.e. water heating). Running the gen up to the bulk level replaces approx 80% of capacity, and maximizes fuel consumption, allowing RE to get the batteries charged the last 20%. Automatic gen start capability with staggered start voltages allow you to target 50% discharge more accurately, and minimizes user interaction. Try to calculate the total daily kWhrs and match the demand with RE as closely as possible. Hope that helps, Rgds, _ Eric Bentsen | Schneider Electric | Solar Business | UNITED STATES | Technical Support Representative Phone: +(650) 351-8237 ext. 001# | Email: eric.bent...@schneider-electric.com | Site: www.schneider-electric.com/solar | Address: 250 South Vasco Rd., Livermore, CA 94551 *** Please consider the environment before printing this e-mail From: Jay Peltz j...@asis.com To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: 08/16/2013 02:01 PM Subject: Re: [RE-wrenches] PV Assist Sent by: re-wrenches-boun...@lists.re-wrenches.org Hi William Thx helps a lot. I can only say how I do it. I'll give the client some options, including the change of appliances and usually the price difference makes the sale
