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L2 fast vs slow charge ~ battery life

Posted: Sun Jan 12, 2020 9:49 pm
by EVMan
For all those, who charge mostly overnight and charging speed is not an issue
what is the better option to charge at L2 in USA.

Reduced 15Amp or 32 Amp ?
What is better for battery life ?

I know 220 volts is like 2% more efficient than charging at 110 Volts, so 22Volts wins over 110 volts

Also does it matter in Winters vs summers ?

Re: L2 fast vs slow charge ~ battery life

Posted: Mon Jan 13, 2020 1:02 pm
by alohart
EVMan wrote:
Sun Jan 12, 2020 9:49 pm
For all those, who charge mostly overnight and charging speed is not an issue
what is the better option to charge at L2 in USA.

Reduced 15Amp or 32 Amp ?
What is better for battery life ?
Less current generally results in less battery cell degradation. 30.1 A is the peak current at 240 V according to Idaho National Laboratory i3 charging tests. That's a C/2 charging rate which isn't very intense, so the difference in battery cell life between 15 A and 30 A is probably insignificant. DC fast charging would be ~2C which would decrease battery cell life if this were the typical charging rate.
EVMan wrote:
Sun Jan 12, 2020 9:49 pm
Also does it matter in Winters vs summers ?
I doubt that battery cell life would be affected significantly based on using different charging power for winter vs. summer.

Re: L2 fast vs slow charge ~ battery life

Posted: Mon Jan 13, 2020 1:21 pm
by EVMan
Thanks Art,
When i said Summers vs Winters, i was mainly referring to the temperature of the battery

As some videos of Tesla suggest, the car tries hard to increase battery temp , while charging, even if that means efficiency is lowered by generating heat.
Apparently Batteries like to be charged when warm and while DC charging, car makes effort to increase temp to 45C to 50C , when nearing full charge
Once charging is complete , it tries to cool the battery

So it may be in winters 30 Amp is desirable to keep them warm, and in summers 15 amp may just do the trick , to generate less eat
Its a one time setting , for a long term, so curious , even if one slightly better than others

I get 247 volts at my home. I have always seen less voltage in commercial street L2s

Re: L2 fast vs slow charge ~ battery life

Posted: Tue Jan 14, 2020 9:41 pm
by jadnashuanh
Many commercial power systems use 208vac, so lower power is more common there versus at a home.