I agree that it is not good to satisfy some firmware deficiency by
putting a very deep cycle on your pack.
Best to correct the firmware, or ignore the problem.
On 7/2/2019 7:41 PM, EVDL Administrator via EV wrote:
On 1 Jul 2019 at 15:24, paul dove via EV wrote:
I think people get confused with the term balancing. It is pretty much a carry
over from lead acid batteries where the take all the cells to boiling to get
them to the same voltage at the end of charge.
That's what I'd call equalization -- forcing current through already-charged
cells or batteries, overcharging them, in order to fully charge others that
aren't yet.
Balancing lead batteries is different from equalization, and similar to
balancing any other cell or battery.
I'm not an expert, but from what I can tell, regardless of the chemistry,
balancing cells or batteries in series usually involves either bypassing
charging current around full cells or modules, or actively using other
cells/modules to charge the cells/modules with lower charge levels.
The goal of balancing shouldn't be so much to get all cells/modules to the
same voltage, but rather to get them to the same state of charge (usually
full). But generally voltage and SOC are considered congruent for balancing
purposes, even though they're not really.
As for periodic deliberate deep discharges, again, I'm not an electrochemist
or anything, but my understanding is that it's not all that healthy for most
batteries. (NiCd is an exception, apparently, but only if you're careful
not to reverse them.)
I suspect that when a discharge to or near 0 SOC seems to increase capacity,
it's actually because it's somehow recalibrating the firmware that manages
the battery. The capacity is still there, it's just that the BMS doesn't
think it is. Running the battery flat, or nearly so, sort of reboots or
recalibrates the BMS. I own a netbook that "finds" some capacity that it's
"lost" when I do this. But I don't like it. I just don't think that's how
you treat a battery if you want to show it you like it.
David Roden - Akron, Ohio, USA
EVDL Administrator
= = = = = = = = = = = = = = = = = = = = = = = = = = = = =
EVDL Information: http://www.evdl.org/help/
= = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Note: mail sent to "evpost" and "etpost" addresses will not
reach me. To send a private message, please obtain my
email address from the webpage http://www.evdl.org/help/ .
= = = = = = = = = = = = = = = = = = = = = = = = = = = = =
_______________________________________________
UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
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
http://lists.evdl.org/listinfo.cgi/ev-evdl.org
Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
