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Discussion Starter #1
I generally try to avoid charging above 80%. (Yes, this probably won't make any difference in the practical lifetime of the car's battery, but this is the first new vehicle I've ever owned, so I try to baby it a bit). That said, I usually do charge to full at least once a week, mainly because charging at work is cheap (free) and at home not so much.

Using the OBD-II reader and EngineLink, I can get readings of both 'Battery % DIC' and 'SoC raw'. When charging from an L2 charger, either at home or at work, typically, it says 'Fully charged' and stops when 'battery %' reads 100% and 'SoC raw' reads 96.04%. I just assumed that this was the battery management system protecting the cells (good) and those last ~4% would always show as unfilled. However, I noticed a few weeks ago when charging from an L1 charger (OEM) in cool temperatures (40F) that it took significantly longer than forecast. Initially said it would be done at 8AM, but adjusted the estimate up to 9AM, then 9:15AM and finally 9:30AM. I had to leave at 9:15AM, and when I checked the reader, it registered 'SoC raw' at 98.1% and still did not claim to be fully charged.

I'm curious whether this difference is simply an accounting issue in the BMS, or whether the battery really did charge more than usual, and if so, why that might be. Thanks!
 

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registered 'SoC raw' at 98.1% and still did not claim to be fully charged
I've seen mine overshoot and then settle out. By stopping the charge, the BMS didn't finish top leveling the cells. My guess, if you had left it plugged in to finish, you would have gotten the 96%.
 

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I've seen mine overshoot and then settle out. By stopping the charge, the BMS didn't finish top leveling the cells. My guess, if you had left it plugged in to finish, you would have gotten the 96%.
So you're saying in essence that the reported '98%' was actually less than the usually-reported 96%?
 

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So you're saying in essence that the reported '98%' was actually less than the usually-reported 96%?
Possible, but doubt it. Not exactly sure of the time frame, but maybe last 20 minutes of any charge session seems to invoke lots of activity of our Bolts. One significant aspect is the car will start temperature conditioning the battery. My guess, is the car does that to get a better baseline for getting in family voltages from the pack. I suspect that you terminated the session before the car did its complete BMS function, but likely you had already received as much charge as you were going to get anyways. All that was thrown off, was the car's estimate of said charge. Maybe you would have gotten a few more electrons in, but it might even be possible that you lose some in the process. Especially on level 1 where the HVAC uses more power than the EVSE can deliver.
 
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