Hello Zeke You must first make sure cells are well in balance by some sort of equalization procedure which involve shunting current from higher voltage cells to the others. Charger is cutoff when a cell reaches above a max set voltage, like 3,65V for example on my Ranger EV.
Does your BMS monitor each cell individually? Is shunting capability installed? In operation, in my experience, if terminals on cells are not well tightened, voltage will fluctuate too low (current demand) or too high in regen. 380 Amps looks amazing high to me. I never go above 150Amps myself with my Ranger EV (104 x 100Ah cells LIFePO4 HighPower) or one of the cells reached below 2,6V. The problem is always worst when I skip equalization, which I have to do manually on my truck. I think what is needed is a monitoring of each cell for voltage, not on total Amps for the pack. To me this data is not relevant. As long as all cells stay above your set point, be it 2,9 or ??? it is fine, In my opinion Denis Le 2014-07-29 à 19:43, Zeke Yewdall via EV <[email protected]> a écrit : > I am programming the BMS, and am wondering what opinions people have on the > sepoints for the BMS, specifically for discharging. > > 24 CALB cells, 100AH, Alltrax 450 controller, DC6.7" motor, 1973 VW bug. > Elithion Lithiumate Lite BMS. > > I did the first serious road test this morning, Default setttings were > 100A continous, and 300A peak for the BMS to start regulating. 2.9 volt > was the low voltage cutoff, with 2.5 volts being the drop dead voltage. > > It was doing pretty good for about 15 miles (60AH or so). It would cut out > under hard acceleration (380 amps or so) and kill the power to the > controller. Under sustained uphill (200 amps or so) it would also cut out > after a while, and would also engage the throttle limiting to keep it to > 100A or so. I would like to set it to 150A continuous, but not sure if > this risks damaging the battery. It's going to live in a much flatter > place than I was doing the test, so maybe 100A is okay. > > The big problems started about 18 miles in -- one battery started going > under 2.9 volts under accelleration, and by 19 miles in, it was severely > limiting current to keep it above 2.7 volts or so -- went to only about 30 > amps, which was essentially undriveable. I either have one cell badly out > of balance (what I'm hoping for), or that's only got about 70AH capacity > instead of 100. If I can correct this one cell and bring it up to what all > the others are doing, am I safe in raising the current limits a little, if > I keep the voltage controls the same? > > Opinions? > > Thanks > > Zeke > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140729/06c8ee17/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) > _______________________________________________ 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)
