12V battery fails after software updates

[ThunderDome]

'21 First Edition - I had automatic updates on until I realized that my car kept going dead after updates. I would take the car out for a couple drives, and like clockwork, it wouldn't start with some combination of error messages. Came to realize it was about the 12V battery (probably being drained during the overnight updates) and therefore, after this last trip to the dealership for a dead 12V battery, I turned off automatic updates so this wouldn't happen again.

It would be nice to start getting updates again without fear that the car will be sitting dead.

Any recommendations for how to handle this going forward?

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[RickMachE]

The 12v battery should not be dying from updates, especially after an update was sent out to specifically address this issue.

Charge the 12v battery to 100% with a trickle charger.

 

[ack154]

Did the dealer replace your battery at that trip to the dealer that you mention? If they didn't, you may want to have it tested and possibly replaced. Like Rick said, it definitely shouldn't be dying just from doing updates (I've gotten warnings for mine in the past - but only after doing literally 3 updates in a row while not plugged in or running, and it still didn't die).

 

[ThunderDome]

Thanks - yes, they did replace the 12V battery this most recent visit. I always have my car plugged in during updates. And if in fact it received that update to address the 12V battery drainage (which update was that, and when was it released?), then I may have to just dip my toe back into the OTA water and hope for the best.

 

[Maquis]

Thanks - yes, they did replace the 12V battery this most recent visit. I always have my car plugged in during updates. And if in fact it received that update to address the 12V battery drainage (which update was that, and when was it released?), then I may have to just dip my toe back into the OTA water and hope for the best.

I wonder if they reset the BMS after replacing the battery?

 

[JohnFoxeSheets]

Plugging the car into power during updates doesn't help and can in fact prevent some updates. (The 12V battery management on the Mach E is not very well designed for this use case, though there have been improvements.) If you're concerned about the 12V battery during OTAs, you could put a battery tender on it when you expect an update. But honestly I suspect your 3-year old 12V battery was the issue and now that you have a new one, it'll be fine...

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