A few questions Lawrence; Is the charger you'll use programmable to a desired cut off voltage?
If so, What is the Max operational voltage for your controller? Maybe you can make your array with as many cells in series as closest to max controller operational voltage when cells at max. be top of charge. Usually this would only happen right at the end of a full charge and would last only a few minutes. But the more cells in series; the more energy and less current in the system. If your charger has a fixed top off voltage, you technically have to attach to that voltage and match the right # or cells in the series circuit. I'm assuming you are using LiFePO4 chemistry because of the 3.3V you mentioned. That chemistry, typically has a max V of 3.65V (3.7V some cases although I wouldn't recommend it). Typical 72V controller can support up to 90V operational (100Vish Max, depending on internal caps). That would be 90/3.65 = 24 Cells in series, then as many strings in parallel >> 87.6V charger cutoff voltage. Hope this can help. Marco Gaxiola On Mon, May 11, 2020 at 1:50 PM Lawrence Rhodes via EV <[email protected]> wrote: > I am having trouble deciding weather 20, 21, or 22 batteries are the right > series string for a 72vdc battery. for a 3.7 volt battery 20 seems to be > right. However I have A123 batteries and nominal is 3.3vdc. Videos on > YouTube are inconclusive. Sellers details not complete. Any advice > appreciated. I'd like to run 1 or two strings for a small ebike battery. > The controller only draws 40amps. Lawrence Rhodes > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > ARCHIVE: http://www.evdl.org/archive/index.html > INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Please discuss EV drag racing at NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20200511/69ac891d/attachment.html> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub ARCHIVE: http://www.evdl.org/archive/index.html INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
