It seems to me there is some wiggle room. I have seen 3.2 to 3.4 top voltage for A123 batteries. Official specifications: Nominal Voltage: 3.3v. Standard Charge: 3.6A. Max Charge: 10C. Max Allowable Charge Voltage: 4.2v Charge voltage is 3.6 volt. Max Discharge: 30C (Continuous) Burst Discharge: 60C. A normal charge on 20 cells would be 72vdc and it could handle up to 84vdc. I am looking at this BMS:
https://www.ebay.com/itm/20S-72V-60V-25A-35A-45A-60A-LFP-LiFePo4-Li-ion-Lithium-Cells-Protect-BMS-IP65/312688099275?ssPageName=STRK%3AMEBIDX%3AIT&var=611407917579&_trksid=p2060353.m1438.l2649 I also inquired about a charger. I don't know however if I need one unit per string or not. I suspect 5ah would be plenty. 2strings. According to the specs one string has just enough power. I don't know if the chargers are smart or not so much to learn. Lawrence Rhodes On Monday, May 11, 2020, 2:08:38 PM PDT, paul dove <dov...@bellsouth.net> wrote: A 3.7 volt battery charges up to 4.2volts. 20 would be 84 volts fully charged. 3 to 2.5 volts x 20 is 60 to 50 on low end so depends on what range you want and the max your system will allow. An A123 is LiFePO4 and they charge to 3.4 volts. 20 is 68 Volts. On Monday, May 11, 2020, 3:50:59 PM CDT, Lawrence Rhodes via EV <ev@lists.evdl.org> 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) _______________________________________________ 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)
