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Overcharging?

Posted: Sat Dec 02, 2017 12:05 am
by voltdave
I am moving to the top of the south high sierras and have a question on charging. If I have it plugged in and fully charged,, then head down the mountain... will the batteries get overcharged from the braking?
Thanks

Re: Overcharging?

Posted: Sat Dec 02, 2017 10:13 am
by leppard3
No, your car will NOT overcharge, but the regeneration will be wasted. Ideally, if you immediately start your trip going downhill, the best option is to stop charging your car before it is fully charged. You would have to experiment to get the best time to unplug.

Re: Overcharging?

Posted: Sun Dec 03, 2017 3:40 pm
by voltdave
Thanks for your reply.
Another volt owner said they read that the volts battery charging system is designed to charge battery to only about 80%. Is this accurate?? If so, maybe the engineers accounted for the "mountain top" charging...?

Re: Overcharging?

Posted: Sun Dec 03, 2017 3:54 pm
by leppard3
It is true the battery is NEVER fully charged OR discharged. It basically only uses the middle range to prolong battery life. It only uses about 65%, I am not sure of the exact range but for example it may only charge to 80% capacity and discharge to 15% remaining before the engine starts, which is basically a generator. You are still running on electic, its just coming from the engine instead of the battery.
So, if you fully charge the battery from an outlet and start a long downhill drive it will NOT further charge the battery. It will not charge above the 80% (or whatever that exact number is). So as far as I can tell, you will have to stop charging the Volt before it is fully charged to recoup the regen power when you start your downhill trek.
The battery management system was very well engineered and seems to be working very well. I have a 2011 with 115,000 miles and still getting the electric range that it got when it was brand new.