I looked at the website for "Johnson Controls" solar cells, It looks sketchy to me. Where is the Johnson Controls part number? Is this used or off spec hardware? "Johnson Controls" is a good name to throw out there, but it seems like more information would be available if it really is the Johnson Controls we are used to seeing. Be careful.
Hopefully some other people here will chime in. The working range of Li ion cells depends on the capacity of the cells - the actual capacity, not some spec sheet capacity. *You cannot use voltage* because the slope of voltage versus state of charge is too flat to be useful. A very tiny change in voltage can have a huge change in state of charge, this an odd characteristic of Li ion cells.. I suggest you work out a way to learn the capacity of at least one of your cells by measuring it. And if you want the best life then you should evaluate all the cells and react accordingly. This is what careful EV DIY'ers have been doing for a long time. You back away from this with increasing risk according to how much unsubstantiated information you pay attention to. If the packs are pre-owned, or not up to spec somehow, you really want to look closely at them. You say you want to operate your EV within a range of "90% of the power." That is a worrisome statement because it is not the right words to use if you understand what you are doing. This "90% range," do you meant you want to have a discharge cutoff at a 5% state of charge, and a charging cutoff at 95% state of charge? You definitely want to bottom balance your pack very well, and have consistent capacities for all the cells to go this low. If you discharge a cell to 0% and keep going, bad things can happen. If you don't understand what I am talking about, please keep learning before proceeding. On Thu, Apr 11, 2019 at 8:46 AM evtlfp20 via EV <ev@lists.evdl.org> wrote: > there balanced fine, I just want to know where the working range for > %90 of the power is. I've heard each chemistry / brand is different. I > found a graph for leaf cells NMC like theses. > > > > > I am not sure what you want the depth of discharge graph for. The cells > > won't be identical and the graph would actually be a band, or range > > about > > an average DOD. > > > > It might be advantageous to measure the capacity of each cell and > > return > > any that seem to far out from the others. If you are not interested in > > that, then you can formulate an useful DOD limit for the pack based on > > the > > capacities. I personally thin balancing the pack at the level of > > discharge > > is best = bottom balancing. Then you can implement a shutoff voltage or > > DOD% with some factor of safety, and select a float charge that is not > > too > > high. > > > > This is fairly laborious, but it protects tour investment. > > > > A car company like Tesla will control manufacturing processes and have > > tight control over the cells construction and capacity, So they can > > build > > a pack without laborious balancing and still get good performance. It > > is > > very hard to get useful information about batteries bought retail, > > wholesale or used. > > > > > > On Wed, Apr 10, 2019 at 2:26 PM evtlfp20 via EV <ev@lists.evdl.org> > > wrote: > > > >> the company is not giving me very much information. they stat a > >> voltage > >> range but I'm looking for a DOD graph, they stat NMC chemisrty not not > >> much more . > >> > >> > https://www.techdirectclub.com/johnson-controls-24-cells-solar-battery-90-vdc-total-2-5-kwh/ > >> _______________________________________________ > >> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > >> http://lists.evdl.org/listinfo.cgi/ev-evdl.org > >> Please discuss EV drag racing at NEDRA ( > >> http://groups.yahoo.com/group/NEDRA) > >> > >> > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Please discuss EV drag racing at NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > -- Michael E. Ross (919) 585-6737 Land (919) 901-2805 Cell and Text (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Tablet, Google Phone and Text -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20190412/7fb440a9/attachment.html> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
