I recommend the iCharger 306B for charging individual cells, it can do
up to 30 amps.
Jay
On 3/13/21 3:29 PM, EVDL Administrator via EV wrote:
John, first of all, a '65 Falcon conversion is a SUPER COOL idea. I'm
jealous. Well done!
Second, I'm far from a lithium battery expert, but I'm having trouble seeing
why you're concerned with "bottom balancing." I don't see why it would be
necessary or even desirable.
As I understand it, the BMS's job is to
(1) Limit and eventually shut down the discharge when any cell is flat
(2) Limit the charge rate when any cell is full
(3) Balance - that is bring up the other cells to full charge without
overcharging the already-full cells
This is how you get the optimum capacity from your battery without damaging
it.
It seems to me that if the BMS can't bring all the cells up to full charge
even with a very long balancing session, then one short term solution is to
individually charge each cell until it's full.
Then see if the BMS can keep the cells properly balanced over a period of
cycling. If it can't, it seems likely that the cells are inconsistent in
usable capacity.
This can be from several causes including
(1) Cells aging at different rates
(2) Some cells newer than others (replaced for premature failure?)
(3) Careless manufacturing quality control which causes inconsistent
capacity and/or varying self-discharge levels
(4) Inconsistent temperature across cells in the battery, which can easlly
happen in coversions where the cells are distributed around the car with
multiple boxes and simple/passive air cooling
(5) Tapping the battery for various loads at different voltages
As I say I'm not an expert and those here who are can probably add to this
list.
I hope that I haven't given you any incorrect information, and welcome
corrections if I have.
David Roden, EVDL moderator & general lackey
To reach me, don't reply to this message; I won't get it. Use my
offlist address here : http://evdl.org/help/index.html#supt
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a smaller boy. I expostulated, but he replied: "The bigs hit
me, so I hit the babies; that's fair." In these words he
epitomized the history of the human race.
-- Bertrand Russell, "Education and the Social Order"
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