Hi Jay and All, While that is true of LiFe, it isn't
as much for li-ion which has a similar charging range as lead. Full is about
4.2vdc/cell and I only go down to 3.2vdc though others go to 3vdc is the
different like between 10.5 and 11vdc, just not much power left to matter going
that deep, not worth the possible damage. Helping, selling
modules for a Solectria E-10 upgrade I was able to match the voltage where the
stock lead charger can handle charging though a bit slow the last 5% and
doubling range at less cost than new lead for the old range.
With Volt module versions I don't even use a BMs for 2 yrs now just charging to
that limit and not going under 3.4vdc and cells still balanced within .02vdc of
each other even with overcharging abuse. BTW you can get 20% more capacity
overcharging as when I had to drive off the overcharge would be 12 miles to get
back to full charge. I wouldn't on purpose but in an emergency I would as no
damage I can tell yet I wouldn't try any f this with other
brands. I only use LG EV cells units because of this as proven.
On Valance modules they have never met spec and die early as likely a 1c
limited rate, just too much internal resistance it seems. I've found high c
rate cells get far longer life like 16c Volt/LG modules that after 6 yrs show
no measurable degradation. Note Tesla's biggest failure was
making low c energy cells for early Powerwalls they had to stop making until
improved. Give me high 4c and up cells or none at all. Jerry
Dycus
On Monday, May 25, 2020, 05:29:58 AM PDT, Jay Summet via EV
<[email protected]> wrote:
The discharge curve for Lithium batteries is very different from Lead.
(it is very flat). There is almost zero sag, but at some point the BMS
will (hopefully!) detect a low cell voltage and disconnect your output,
causing the whole scooter to stop without warning. (If it fails to do
so, the lowest cell will get reversed and die in a potential blaze of
glory...)
You can expect the range to be higher than lead batteries, but the "drop
off" to be sharper at the end. If you are monitoring voltage, it will be
in the "nominal" range until right before you run out of juice, at which
point it will start to drop very quickly. So there is less warning of a
"low tank" unless you have an amp hour (or watt hour) counter and know
the capacity of your battery.
Jay
On 5/24/20 11:51 PM, Lawrence Rhodes via EV wrote:
> After riding 14 miles in two trips over two days or more and letting the bike
> sit for days starting voltage 26.38vdc or higher. A few hours ago voltage
> 25.97vdc. Now 25.90. These Valance 40 ah lithium do not act like lead. Lead
> 40 ah will give 20 miles. Will my batteries soon drop precipitously? I guess
> I should ride down to 25vdc and check how far I have gone. This is carrying a
> 240 pound person and up my hill twice. The batteries put out 30 amps
> continuous. Lawrence Rhodes
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