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)
