[ballen1923]

I have an '18 Bolt EV with 7,000 mile on her. Been perfect. My question relates to the battery. I do not drive a lot and keep the battery charged each night to the 80% with Hilltop Reserve active all the time. I have never gone below the 100 mile range on the GOM. I live in the upper mid-west so we get very cold winters and hot summers too. But the Bolt is always garaged.


Do you think I should let the battery run down to near zero charge periodically, then charge it back up? I have no idea if this would be of benefit or not. Any suggestions would be appreciated.

 

[psyflyjohn]

Absolutely not. Discussions have suggested that letting the car go to about 20-30% charge and using the 80% hilltop setting is likely best for the battery. Discharging to near zero was for nicad batteries, not lithium ion.

 

[redpoint5]

Keep doing what you're doing. That's about the best scenario for the battery longevity. I've heard the Bolt can top balance even in Hilltop mode, though I haven't confirmed this.

 

[JPT]

I've heard the Bolt can top balance even in Hilltop mode, though I haven't confirmed this.

While I haven't seen any good supporting documentation for this, I believe it to be true too based on the end of (hilltop mode) charge rates that I see from my JuiceBox.

 

[redpoint5]

While I haven't seen any good supporting documentation for this, I believe it to be true too based on the end of (hilltop mode) charge rates that I see from my JuiceBox.

Yes, I've heard that before too, and agree that it's a pretty compelling theory. There's no other reason for a taper charge when only going to hilltop state of charge.

Not only that, but balancing isn't as necessary when the battery is maintained in the middle region of charge since even out of balance cells won't be nearing the top or bottom end of their capacity.

 

[raitchison]

Yes, I've heard that before too, and agree that it's a pretty compelling theory. There's no other reason for a taper charge when only going to hilltop state of charge.

Not only that, but balancing isn't as necessary when the battery is maintained in the middle region of charge since even out of balance cells won't be nearing the top or bottom end of their capacity.

Well it seems that you could maaayve have a situation where over a long time one cell could drift from the rest over time and a lot of incomplete charge cycles. That's the main reason why I charge to "full" (with Hill Top Reserve) every 1000 miles or so. Still I haven't seen any evidence of that happening over that period of time/use.