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Best way to check 12V Battery?

12593 Views 53 Replies 17 Participants Last post by  240vPlug
It's becoming apparent from posts on this forum and others that the 12V battery is somewhat of an Achilles heel for the Bolt. I know that lead-acid batteries have a finite life, and it seems that when they give up the ghost on Bolts they can create a variety of problems.

My question: What's the best way to monitor the battery status besides waiting for a problem to occur (which of course, will be at an inconvenient time). A routine check with a multimeter? I know that the Bolt system tries to keep the battery charged, so a good reading may be inaccurate on a weak battery. I could "load test" the battery, but would probably have to disconnect it to do that. Your informed opinion would be appreciated.
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Thanks to the interesting info in this thread. I just returned from 4 weeks of traveling, I left my garaged 2019 Bolt plugged in while gone. My charge settings are set to charge to 75%. I use a JuiceBox Charger. I use a digital multimeter to check the voltage and over the past few months my battery has ranged between 12.8v & 12.5v. I've gotten lazy and rarely record the voltage any more. I didn't record the voltage before I left on my trip, when I checked it before leaving I found it within the above mentioned range and didn't feel recording it was necessary.

When I left on my trip I left the windows rolled down and the hood open...just to cya. When I checked the battery on return it was 12.0v, charger still plugged in, green light on dash showing fully charged (to my setting of 75%). I unplugged the charger and an hour or so later the battery was at 12.3v. Still, that is the lowest reading I've measured since owning this car. Drove it today and all seemed normal.

I'll start tracking the voltage again.
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Opening the door to pop the hood wakes up the car. It will give a false voltage reading.
Right. You mentioned sometime in the past the issue of popping the hood. So I try to remember to pop the hood the night before I plan to take a reading and then "sneak up on the bolt" in the morning to get the reading :D

I was unaware of the importance of not having to fob nearby. I don't think I had the fob when I got the 12.0 reading but I might have had it when I did the next reading. So many things to remember.....
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