12v Battery Issues and Updates

[PNW_Chris]

Have a 2021 Premium Mach-E. No issues with battery but since it was 4.5 years old, thought I'd get ahead of the game and replace the 12v Battery for piece of mind. I picked up the Same as OEM battery from Rock Auto for much cheaper than the dealership. Installed it and seemed to have no issues. I'm now a couple of months in and noticing that the car will not update. We drive the car daily sometimes short sometimes close to an hour at a time and noticing that my SOC isn't going above 69% which I'm assuming is the reason for the updates failing. (Car Scanner showing 14.4 volts and 69% SOC) Advice?

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[kennelh]

Have a 2021 Premium Mach-E. No issues with battery but since it was 4.5 years old, thought I'd get ahead of the game and replace the 12v Battery for piece of mind. I picked up the Same as OEM battery from Rock Auto for much cheaper than the dealership. Installed it and seemed to have no issues. I'm now a couple of months in and noticing that the car will not update. We drive the car daily sometimes short sometimes close to an hour at a time and noticing that my SOC isn't going above 69% which I'm assuming is the reason for the updates failing. (Car Scanner showing 14.4 volts and 69% SOC) Advice?

Check @dtbaker61's thread, specifically resetting the BCM.

 

[Mach-Lee]

Did you forget to reset the BMS when you changed the battery? If so, then reset it.

See "How do you reset the BMS?" https://www.macheforum.com/site/threads/12v-battery-faq.32744/

Car Scanner showing 14.4 volts and 69% SOC

FYI, this is because the battery is charging. You can have a battery at 69% SoC and 14.4V while it is charging up. However you should be able to reach 90%+ after several hours of driving, if not then the BMS may be inaccurate and require a reset.

 

[dtbaker61]

...and if you typically take short drives, you *should* periodically:
- turn vehicle on
- disable setting>vehicle>auto-off
- leave vehicle "on" for 12-24 hrs

this will charge 12v to 100%, and desultfate

 

[PNW_Chris]

Good ideas! I'll resetting the BCM first and if no joy, will do the power-on for 12+ hours!

 

[Misterrobot]

...and if you typically take short drives, you *should* periodically:
- turn vehicle on
- disable setting>vehicle>auto-off
- leave vehicle "on" for 12-24 hrs

this will charge 12v to 100%, and desultfate

Good day! What would be considered “short drives”

Ron

 

[dtbaker61]

Good day! What would be considered “short drives”

Ron

daily commuting is all "short" since the car is on for less than 2 hours.... which is not enough time to get the 12v up to 100% and hold it there long enough to desulfate.

If you purposely drive your HV down to 10% once in a while, and slow charge (overnight) for 10-12 hours, that is pretty good for the 12v battery.

Better to leave the car "on" for a full 24 hours.... perhaps once a quarter. I try to do it when I rotate tires (every 5,000 miles).

 

[Misterrobot]

daily commuting is all "short" since the car is on for less than 2 hours.... which is not enough time to get the 12v up to 100% and hold it there long enough to desulfate.

If you purposely drive your HV down to 10% once in a while, and slow charge (overnight) for 10-12 hours, that is pretty good for the 12v battery.

Better to leave the car "on" for a full 24 hours.... perhaps once a quarter. I try to do it when I rotate tires (every 5,000 miles).

Thank you sir! I am 17 miles one way on the intestate. I’ll keep your suggestion in mind.

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