12V Battery Charging Facts

[Shayne]

I think since 21 they've changed 12v battery management. On my 23.5 out of curiosity I check the 12v SOC. in eleven months it's never read less than 80% on the ford.com site and usually resides in the 85-95% range. The BEV team when I was discussing an issue with charging as an aside told me that some OTAs require 80% battery state of charge to work.

He needs an OTA update to fix why it can not OTA update? Ford care and logic

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[noway]

I have a 2021 Job 1. I haven't received an OTA since the Tesla Supercharger update many months ago. Every time I check my 12V it's never higher that 67%, even after drives of 45 minutes or a L2 charge to 90%. Is this normal? Is my low 12V charge why my OTAs have stalled?

If it cannot reach 100% it is because the BMS is out of sync and think the battery can receive more energy than it actually can. This can be due to tempereture/environment changes or degradation/sulphation, it did not seem to be able to adapt fast enough. Solution to this is to reset the BMS (search google or forum for "ford BMS reset"). After resetting BMS it will calculate SoC only from typical voltage+current+temperature. It will however need to drain the battery some times before it will know how much energy it can hold after reset to get the low range SoC correct

If you wait it out it will eventually get to 100%, but not because it has charged it more, but rather because the BMS slowly calibrates

On the other end, if it constantly reaches and stays at 100% I would worry more, because it indicates BMS thinks battery can hold more than it can, and low end SoC may be incorrect, so I would not do anything If it can reach past 95%