These little cell loggers work great - one logs and one just displays. http://www.ebay.com/sch/i.html?_nkw=celllog
On Thu, Jun 23, 2016 at 1:21 PM, paul dove via EV <[email protected]> wrote: > I assume you want a way to discharge the cells to find the culprit? > Get something like this..... > 250watt 0.1 ohm Resistorhttp:// > store.evtv.me/proddetail.php?prod=250wresistor > and one of these because you can hook up to a PC and record the data with > time stamps. > TekPower TP4000ZC PC based RS232-Interfaced Auto RangingDigital > Multimeter, MS8220R Alikehttps:// > www.amazon.com/TekPower-TP4000ZC-RS232-Interfaced-Ranging-Multimeter/dp/B000OPDFLM > You can do groups like Cor said to narrow it down. You should see a > significant difference in voltage drop under load if you have a bad cell. > You can also use this meter to easily calculate amp hours in or out since > you can save the data to an spreadsheet format. > You could also buy a powerlab 6 because they will discharge as well. Or a > regular battery load tester. > They make them for lithium chemistries. Something like this should work. > > https://www.amazon.com/Tenergy-Intelligent-Capacity-Discharger-Resistance/dp/B0178P8H9U > > Unless I misunderstood what you are asking. > In addition to how fast the voltage drops you can measure the resistance > of the cells and the speed at which the cell recovers voltage after > removing the load. You should be able to spot one out of family. > > > > From: Mike Beem via EV <[email protected]> > To: Electric Vehicle Discussion List <[email protected]> > Sent: Thursday, June 23, 2016 1:02 PM > Subject: [EVDL] Lithium Battery Testing > > I spent some time looking through the archive, but couldn't find what I'm > looking for--> I think I have one weak cell in my 40 cell 100 Ah pack; I'm > getting a low battery signal (mini BMS) under load when there is more than > sufficient range left on the charge. These are CALB batteries which I > installed in December 2012. I recently tried going through and individually > charging each one to 3.5v (after charging the whole pack to shut-off point) > with my variable power supply, and at 2 amps maximum, it took me almost 2 > weeks of not driving the EV (http://www.evalbum.com/4181) to get all the > way through, so I used a timer, which of course, would defeat the whole > process by not being able to WAIT for 3.5v on every one... > When I first started driving it with the new pack in 2012, it did have the > 40 mile range I aimed for when I put this together. I have only driven it > to the limit of the pack once since then, and it was in a colder winter > than we usually have, so I wasn't surprised to have much less range. > I need an easy to put together load I can use with a voltmeter to test > cells, and a range for what voltage drop on these CALB cells would be > normal or weak. I got fairly good at this with lead acid, both flooded and > AGM, but don't have the experience or science to know if, 1) this is a > reasonable way to proceed, and, 2) what those voltage-drop decision points > would be, and, 3) what components to use for the load? > Thank you! > Michael B > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20160623/fd3e157a/attachment.htm > > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Read EVAngel's EV News at http://evdl.org/evln/ > 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/20160623/dd0840c1/attachment.htm > > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Read EVAngel's EV News at http://evdl.org/evln/ > 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/20160623/e729bb36/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
