Off-gridders usually have a genset for the low insolation periods. Try a used Prius?
On December 22, 2014 7:36:30 AM CST, Michael Ross via EV <[email protected]> wrote: >Hi Ben, > >What SRPs CEO knows and you will find out is you are diving into a >rabbit >hole. It is not a rational world down there, yet. > >I will just talk about batteries. > >It is important to know what your present and future power needs are. >For >instance, I just has a six week period this past July and August where >my >PV system made an average of 8kWh a day - I use 23kWh. As I write this >it >is completely dark and gray outside and raining once again. Obviously, >my >5.6kW system is not big enough to span the time I may need more power >than >I can reasonably make even with battery storage. A good month where I >break >even with Duke Energy, I make 23 to 30 kWh a day. To go off grid have >to >guess what I will need to save for my location and it is probably at >least >3 days worth of average use - based on current needs (no EV to charge) >- >round up to 100kWh at 120 and some 240VAC. > >You need to be brutally honest about your weather, how you feel about >your >use of power, and your willingness to go with far less power or without >completely for some periods of time. I see you live in a sunny place, >AZ, >but be honest - is it ever not sunny, and how well will your system >deal >with the worst case. How well will your wife an daughters, and so on. >How >have to design for the worst case and decide what you can manage., > >In this way the grid is worth something to us all. > >On the battery front - you live an a place that gets quite hot, it get >hot >when have a lot of sunlight. This means you will subject your >batteries to >the worst possible conditions for their life - high heat and high state >of >charge. You should know that Leaf batter packs are proving to be very >a >lot of trouble in AZ and SoCal where they get hot, and Nissan did not >make >provisions to col them. Some packs have lost 27% of their capacity in >a >year and lawsuits are in process. The heat is killing them. You are >going >to need to cool the system actively. You need to know what the exact >cells >are in it and their particular needs. A mixed pack will need to have >climate control for the worst cells in it. > >Consider this LiFePO4 cells start to have real problems at 40°C (104°) >and >high states of charge. NMO at 35°C. > >This is a fascinating lecture in Li Ion batteries. [The fellow giving >it >Dr. Jeff Dahn, really knows what he is talking about (he has been >working >on Li ion since 1978, one of his main collaborators is now the head >engineer at Tesla for battery life, and another is building and selling >high precision cell test equipment for Bosch, Tesla (Panasonic), ATL, >and >others)] > >https://www.youtube.com/watch?v=pxP0Cu00sZs > >A list of Electorchemical papers is here: >http://www.dal.ca/diff/dahn/publications.html The 1st one >chronologically >is #422, and search on A.J Smith and J.C Burns for subsequent ones. > >In a nutshell the lecture says that most Li Ion battery testing in the >past >has been unable to evaluate long term performance. What happened to >Nissan >is liable to crop up with any EV packs out there (except perhaps >Tesla), >and you need to account for this with any home storage plan. If you >try to >use PbSO4 then they are more forgiving, but still a very expensive and >tricky proposition. > >In truth every Li ion chemistry, electrolyte package, manufacturer, and >form factor is a little unknown world unto itself, and the data on how >to >manage them for longevity is not yet available. You make a mixed pack >from >used EVs and you are asking for trouble. > >The questions is, are you offended by SRP so much that you would drop >$10k >to $20K to make a reliable home storage system? Or would you rather >send >the to SRP in little monthly bits for 30 years? > >Here is how it would look for me - > >Duke Energy charges me $19.50 a month when I net to no power use for >them. >Applying no time value of money - that is about 500 months before I >break >even on a $10K storage system. > >Roughing it out further, I would need to at least double my PV capacity >(I >have already gotten all the tax credit I can get, so I would spend $30K >for >an additional 6kW system with really quality components (Sunpower has >the >best chance of actually lasting 30 years) to meet my worst case needs, >And >I would probably be having some times of very low available power with >this system when I would have to be very conservative in my use of >stored >power. If I charge an EV I need even more. The storage system is >probably >$20K. $50K out of pocket. > >I am not happy with my utility, but I like my money more. In 30 years >I >can triple that $50K with conservative investing practices. The >heartache >of and time going into design a home storage system is not appealing >either. It will be risky and if you get it wrong the extra cost high. > >I believe simply waiting 10 or 20 years to see how all this shakes out >is a >smart move. Maybe buy some stock in Tesla and SolarCity - or similar. >Domestic storage is coming, doing it DIY right now sounds like a >foolish >and costly endeavor. > >I suspect that SRP and Duke have done their home work on this. I bet >they >know that tripling the grid use fee to you is actually what the market >will >bear. Be careful assuming they have done this wrong. > >MIke > > >On Sun, Dec 21, 2014 at 3:24 PM, Ben Goren via EV <[email protected]> >wrote: > >> So, I have my roof covered with solar panels. And Salt River Project, >my >> utility, is threatening to at least triple monthly "basic connection >fees" >> for solar "customers." >> >> I've decided that's not an option for me. Before I pay such Danegeld, >I'll >> get a bunch of batteries and drop off the grid entirely. (And I wrote >as >> much in a letter to SRP's CEO.) The rate increase is still in the >proposal >> stage and there'd be a period of some years before it'd go into place >for >> existing "customers"...but, still, now is the time to start planning. >> >> As I see it, I have two main reasonable options for the battery: >> nickel-iron or something discarded from an EV. >> >> Nickel-iron would either be expensive to purchase or a significant >> investment in time to make, but it should last forever. >> >> A few surplus / used / whatever EV batteries would presumably be much >> cheaper, but have a much more limited lifespan. >> >> Part of me would be inclined to go the nickel-iron route and never >have to >> deal with it again. >> >> Another part suggests to do things as cheaply as possible, even if it >only >> lasts a few years, because battery technology is improving so >rapidly. >> >> So...can anybody offer any suggestions? For example, what to expect >to pay >> for EV batteries that're no good for use in an EV but still hold >enough >> charge to be worth putting at the back of a closet? >> >> I'm assuming the battery output will go into the DC input on the >inverter >> I already have for the PV panels, and that, in turn, means that I >don't >> have to worry about matching voltages from different batteries. That, >for >> example, I should be just fine getting a surplus Leaf battery from >here and >> a Tesla battery from a wrecking yard there and so on until I've got >enough >> amp-hour capacity for my needs, and that I can add and remove >batteries >> later as the fancy tickles me. Is that a valid assumption? >> >> Anything else I should consider or start thinking about? >> >> Thanks, >> >> b& >> -------------- next part -------------- >> A non-text attachment was scrubbed... >> Name: signature.asc >> Type: application/pgp-signature >> Size: 801 bytes >> Desc: Message signed with OpenPGP using GPGMail >> URL: < >> >http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20141221/aab757b4/attachment.pgp >> > >> _______________________________________________ >> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >> http://lists.evdl.org/listinfo.cgi/ev-evdl.org >> For EV drag racing discussion, please use NEDRA ( >> http://groups.yahoo.com/group/NEDRA) >> >> > > >-- >Put this question to yourself: should I use everyone else to attain >happiness, or should I help others gain happiness? >*Dalai Lama * > >Tell me what it is you plan to do >With your one wild and precious life? >Mary Oliver, "The summer day." > >To invent, you need a good imagination and a pile of junk. >Thomas A. Edison ><http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html> > >A public-opinion poll is no substitute for thought. >*Warren Buffet* > >Michael E. Ross >(919) 550-2430 Land >(919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Google >Phone >(919) 631-1451 Cell >(919) 513-0418 Desk > >[email protected] ><[email protected]> >-------------- next part -------------- >An HTML attachment was scrubbed... >URL: ><http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20141222/c8c02102/attachment.htm> >_______________________________________________ >UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >http://lists.evdl.org/listinfo.cgi/ev-evdl.org >For EV drag racing discussion, please use NEDRA >(http://groups.yahoo.com/group/NEDRA) -- Sent from my Android device with K-9 Mail. Please excuse my brevity. -------------- next part -------------- An HTML attachment was scrubbed... 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