George Mullineaux via EV wrote:
Here at work, we have some evs for moving equipment and boom lifts. I was under
the impression that the slow charge after the 80% level was for deep charging.
We have two trolleys that have been charged in this manner for 6 years on the
same batteries. I wonder if maybe the fact that they are lead-acid makes their
charging properties different? I am not extensively trained with evs, just go
with what I have been told. I do love to learn.
Hi George,
Pretty much all battery chemistries (lead-acid, nickel-, and lithium at
least) benefit from a slower charge rate as they approach "full". The
rule of thumb is to slow down charging above 80% state of charge.
Over-charging also shortens the life of the battery. The extra energy
doesn't get stored as charge; it gets converted into heat, gas, and
other destructive side reactions. If it's a "flooded" battery with vent
caps, you can replace the water lost. But you can't do this with sealed
batteries (and all lithiums are sealed). They simply "die young" when
enough over-charging has accumulated.
Hope this helps,
Lee Hart
--
A designer knows he has achieved perfection not when there is
nothing left to add, but when there is nothing left to take away.
-- Antoine de Saint Exupery
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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