Should I DC fast charge to 100%?

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jasonring

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Apr 1, 2017
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I found out that ChargePoint installed 1 level 3 DC fast charge station in my neighborhood recently. I wonder if it is ok to use DC fast charge station to charge my e-golf from 25% to 100% once a week. Will this kill the battery?

I am leasing the e-golf for 30 months (7500 miles per year). Will I see severe battery degradation before the end of the lease?
 
No, I don't think you see severe degradation over 30 months. The VW manual says to avoid "frequent and consecutive" DCFC sessions and to follow a DCFC session with L2 charging. If you are leasing and don't own the battery, then there is no warranty or longevity concern for you. I don't consider once a week frequent. I would consider twice a day frequent. If you live in a cold climate, then there is probably very little issue as battery degradation is a function of temperature and battery cycling habits (avoid letting the battery sit at 100% for extended periods, try not to charge to more than 80% or 90% SOC routinely, and don't routinely cycle the battery from 0% to 100%). If you want to baby the battery, you may be better off going from 15% to 90% than from 25% to 100% to get the same range. Best of luck.
 
Another reason NOT to charge to 100% is that you'll lose some regenerative braking, and so you'll feel a difference in performance near 100% SOC than you would at 90% SOC. When you charge to 100% SOC and then brake, the car will default to friction braking because there is very little capacity left to charge the battery, so as you drive the way the car brakes will change. If you don't care about this, then charge to 100%, but by charging to 90% you will get a consistent braking experience throughout the rest of the battery capacity range down to 15% SOC.
 
There is usually a time limit of 30 minutes on a DCFC, and if others are waiting in line to use it, 20 minutes would be preferred for an up to 80% SOC. The last 10% is very slow going, and poor use of a DCFC level 3 device. Do your top charges to 100% on a Level 2 or Level 1 EVSE.
 
How the very cold weather can impact battery life ?
I'm living in North California in Bay Area right now and it's one of the best place for battery, I guess.
But I'm thinking about moving to NJ and there is very cold sometimes, like 5-10F.
Is it also bad for battery?
 
I live in the mid-Hudson Valley of NYS and have had my 2015 eGolf since DEC2014. Our winters are slightly colder than those in NJ. At 29K miles I have not observed any obvious degradation in range. I have never DCFC since all my charging is via level 2 in my garage. So, cold temperatures in my region have not been bad for the battery.
 
Cold weather does not permanently degrade the battery like hot weather does, but it won't hold as much of a charge until it warms up.
 
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