-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Here is my non-technical understanding:
If you are charging "flooded" (non-sealed, with a vent) lead acid batteries, you can bring all batteries to "maximum" SOC (on a per-battery basis) by charging the entire string (hopefully at a low-ish amperage) until they are all fully charged. Batteries that are fully charged will simply shed excess power as heat (if the amperage is low) or as heat and bubbles of H2 and O2 gas (if the amperage is high enough to "bubble" them). [This is why you replace the H2O (water) with distilled water every so often...] Batteries that are not fully charged will keep charging until they are fully charged or the charger turns off. The voltage of each cell may still be different, as well as the actual amp-hour capacity of the batteries, depending upon chemistry and manufacturing differences, level of water, specific gravity, etc, etc etc... So they will be "balanced" in that all batteries will be at 100% SOC....but they could still have different capacities (such that the weakest battery will reach zero SOC before the others.......) Jay On 02/03/2014 01:54 PM, SLPinfo.org wrote: > Cor, > > I didn't want to hijack Michael's thread so I'm starting a related one. In > your recent message to him you implied that with subsequent charging a > series pack can actually move closer together (i.e., become more > balanced). Is that really true? I'm not questioning your judgement here - > I really want to know. I had assumed that the best you could hope for was > that the overall balance would stay relatively stable and only drift > further apart as the batteries aged. > > This is quite timely for me. When I recently replaced my pack of 15 @ > T-875s I was in a hurry to get my truck back on the road and had to accept > the set that my supplier got for me (he gave me a good price and delivered > them for free). Unfortunately the initial spread was 0.11 volts from > highest to lowest when they arrived. After about 20 cycles I let them rest > for 24 hours and the spread was the same. But this morning, after 48 hours > of rest (and about 60 cycles of use) the spread had dropped to 0.07 volts. > Most of the difference appears to be due to the batts with the highest > voltages (8.59 volts) dropping by 0.05 volts to 8.54 volts. That would > seem to be more than just measurement error, so it seems to confirm your > implication that the pack could in principle become more balanced. I > certainly welcome the possibility. > > Your thoughts? Comments from others also welcome of course. > > > Peter Flipsen Jr > http://www.evalbum.com/3739 > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140203/aa762ee8/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) > -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Using GnuPG with undefined - http://www.enigmail.net/ iEYEARECAAYFAlLwBC0ACgkQSWJjSgPNbM9krACfY+hw1wxDF7PSh5qUoG2BfGDp 3jYAnRONVv3161sK5j/kvIYIlpPmo0YM =asqC -----END PGP SIGNATURE----- _______________________________________________ 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)
