jdunmyer
Posts: 41
Joined: Mon Oct 10, 2016 10:18 pm

Gauging battery health

Thu Oct 03, 2019 3:23 pm

For someone wanting to buy a used Bolt, is there a way to guage battery health? Mileage alone wouldn't necessarily be a good indication; i recently watched a U-Tube video of a fella with a Bolt that has 100,000 miles on it. He claimed that his battery had lost only 9% of its original capacity. Simply charging to 100% and reading the GOM mileage would be highly dependent on how it's been driven recently.

Thoughts?

SeanNelson
Posts: 1451
Joined: Tue Jul 05, 2016 2:43 am
Location: Vancouver, BC

Re: Gauging battery health

Thu Oct 03, 2019 3:31 pm

jdunmyer wrote:For someone wanting to buy a used Bolt, is there a way to guage battery health? Mileage alone wouldn't necessarily be a good indication; i recently watched a U-Tube video of a fella with a Bolt that has 100,000 miles on it. He claimed that his battery had lost only 9% of its original capacity. Simply charging to 100% and reading the GOM mileage would be highly dependent on how it's been driven recently.

You're exactly right by pointing out that the car's range estimate has no strong correlation to battery health. The way to judge battery capacity is to fully charge the battery, drive it until it's empty, and check the energy information screen to see how many kWh you were able to draw.

If you don't have the opportunity to drive that far, a bit of a shortcut method is to use the MyChevy app, which reports the battery's state of charge as a percentage. Check the SOC and the kWh used at the start of the drive, drive as far as you can, and check them both at the end. This lets you compute a very approximate battery capacity. For example:

40 kWh used at the end of the drive minus 30 kWh used at start of drive = 10 kWh used.
70% capacity at the start of the drive minus 50% capacity at the end of the drive = 20% capacity used.
100% / 20% x 10kWh = approximately 50kWh battery capacity.

marspilgrim
Posts: 21
Joined: Tue Jul 30, 2019 10:13 pm
Location: Chicago

Re: Gauging battery health

Sat Oct 12, 2019 8:14 pm

Unfortunately there isn't a way to find out before you purchase the car. I got my 2017 a couple months ago with 21K miles, knowing that the Bolt has thermal management and I did months of YouTube research also. If you find a used one that has a reasonable amount of annual mileage on it I wouldn't be concerned at all. If you find a 2019 with 30K miles on it, I'd avoid those and assume it was a Uber driver, which in that case there will be extra wear in the passenger areas also that needs some close inspection. You probably watched the News Coulomb channel? He's done a ton of long distance and fast charging, way more than most people ever will and his Bolt is holding up extremely well. After narrowing down my choices to the Bolt or a Leaf, I watched many hours of reviews and went with the Bolt EV as the best long term car for me. I plan on keeping it 10-12 years but I only drive about 7000 miles a year with my commute and local errands.

I've only done a full charge once just because and the estimated range was 293 miles on the middle number. I did get the OBDII thing and the EngineLink app but I don't see State of Health (SOH) in it, but I may not have the file set up correctly.

Just get the VIN and make sure there aren't any open recalls on it. Some early Bolt's had some battery cells needing replacement under wty.
2017 Bolt EV Premier

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paulgipe
Posts: 173
Joined: Mon Feb 20, 2017 12:39 am
Location: Bakersfield, California 93305
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Re: Gauging battery health

Mon Oct 14, 2019 9:16 pm

marspilgrim wrote:Unfortunately there isn't a way to find out before you purchase the car. I got my 2017 a couple months ago with 21K miles, knowing that the Bolt has thermal management and I did months of YouTube research also. If you find a used one that has a reasonable amount of annual mileage on it I wouldn't be concerned at all. If you find a 2019 with 30K miles on it, I'd avoid those and assume it was a Uber driver, which in that case there will be extra wear in the passenger areas also that needs some close inspection. You probably watched the News Coulomb channel? He's done a ton of long distance and fast charging, way more than most people ever will and his Bolt is holding up extremely well. After narrowing down my choices to the Bolt or a Leaf, I watched many hours of reviews and went with the Bolt EV as the best long term car for me. I plan on keeping it 10-12 years but I only drive about 7000 miles a year with my commute and local errands.

I've only done a full charge once just because and the estimated range was 293 miles on the middle number. I did get the OBDII thing and the EngineLink app but I don't see State of Health (SOH) in it, but I may not have the file set up correctly.

Just get the VIN and make sure there aren't any open recalls on it. Some early Bolt's had some battery cells needing replacement under wty.


There is a line in the OBD spreadsheet for Bat Capacity kWh. That's what I am using to track a minor amount of battery degradation. See Battery Degradation Comparison Chevy Bolt EV and Nissan Leaf .

Paul
Paul Gipe
2017 Bolt LT with DCFC, leased 11/09/17
2015 Nissan S with QC, leased, returned
2013 Chevy Volt Premium, used, sold
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