Does the e-Golf only truly level it's battery cells when touching a full 100% charge, or do they level during all L2 charging? When charging to a specific decile, like 70% or 80%? Is there harm in charging for a specific window of several hours each day, ending at a specific time and leaving the battery at a random SOC of, say, 68%?
I find VW's charging protocols abominable. Everything is either tied to charging immediately, or to a departure time. I'm self employed, so the idea of leaving at a specific time every day is foreign to me. Since the battery of the car is big enough that it is only on long trips that I want to charge towards the top of the battery, my ideal regular practice is to charge when power is cheap and clean. e.g. running from my solar array, or running from the 80% of my grid power that comes from a nuclear plant 50 miles away, which I can count on being all nuclear and no natural gas at night. My interest is in charging my e-Golf at a relatively gentle rate during those periods (say 13 amps and 240 volts), most typically from about 8 am to around noon or 1 pm, to minimize battery capacity loss. In my mind, anything close to a 70% reduction in range in 100,000 miles would constitute a horrible failure. In 81,000+ miles on my '13 Volt, my battery still charged to 4.036 volts in each cell in summer. Perhaps 1% range loss in four years and that many miles. Too small to measure with certainty. But I had to burn gas on long trips, so I switched to the '17 e-Golf, which allows me to do long trips without any gas at all, and that can charge at a full 30 amp L2 charging rate, and has the DC charging option.
My interest is in practicing charging during a specific window in time, to whatever level that achieves. Whether it's 74% or 82% doesn't really matter to me, since day to day I only use about 1/4 or 1/3 of my battery's capacity. I do not get net metering from my utility, so when I come back from long weekend trips I have an opportunity to drink up a substantial amount of my solar over two or three days, for example taking my battery from 28% to 64% the first day, 36% to 72% the second, 47% to 83% the third, and so on. Yet VW could not conceive on a circumstance where someone would simply want their car to stop charging wherever "off-peak" time ran out, and stop when power became more expensive or dirtier. Since I do not have a regular departure time, I just want to bank a reasonable amount of clean energy into it each day. It's rare I know in advance exactly when I'm going to leave.
All they had to do was offer a charging option to charge only during "off peak" rate hours. Without a departure time, their complex screens do not allow for such a protocol. Not without a burdensome amount of math every time one arrives home to set up charging for the next day. It's astounding to me they haven't, particularly given they do nothing to dispute that gentle charging tends to be easier on a battery, and charging to a lower peak voltage allows for more watt hours of throughput for a battery over its lifetime. Nor do they guarantee it won't matter. 30% range loss is a largely empty guarantee for anyone willing to do what's necessary to do better. I just don't buy Cattlerepairman's presumption that presumption #2 is correct in his hypothetical, particularly if it means I have to be the guinea pig.
. Leaf's battery lost 4 out of 12 bars, 33% degradation. We can always take a cab for emergencies from work since I live in a large metro area.
