12V Battery Days Reset after FDRS Software Update

[MichiganMatt]

I have a 2022 Premium AWD Extended Range, about 26K miles on it. This past weekend, I used a Mongoose cable to update all of the modules in my car using FDRS software.
It was first time doing the update and I had quite a few modules that needed it so I'm glad I did it. It went well, and the all of the guidance in this forum made me comfortable doing it.

When I was done, I cleared and re-tested for any set codes, everything looked good so I put cover back on under the hood (after loosing 1 clip, of course) and I called it a day. I noticed the next day that the 12V Car Scanner value that the 12V Battery Reset Days value in my OBD2 scanner went to '0' and it's gone up each day since then.

I was not having any 12V battery issues before the update , and the whole time I was doing updates (about 4 hours) it was connect to an external 60A power supply. I'm assuming one of the clear and re-test procedures set the battery to '0' days. I got the car used but I'm pretty sure it's still the factory original battery in the car and I have not had any problems with it since I got it. I'm in Michigan, and my experience has been that 12V batteries here last a long time, other cars I have owned seem like they last 10+ years as I can't remember replacing them before the 10 year old mark.

So my my question is, would it be best to disconnect 12V battery, charge to 100% with an external charger, then do another 12V battery days reset for the counter? I also considered swapping a new 12V battery, but I've not had any issues in the 7 months I've owned it and I hate to replace things before they need it.

I attached an image from Car Scanner app of the 12V value I'm talking about.

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[Mach-Lee]

Yes, the current BCM update will reset the learned values unfortunately. You can leave the charger or power supply on it overnight, then it should be fine afterwards. It will learn the SoC accurately in the next few days.

 

[MichiganMatt]

Yes, the current BCM update will reset the learned values unfortunately. You can leave the charger or power supply on it overnight, then it should be fine afterwards. It will learn the SoC accurately in the next few days.

Thanks for the quick reply Mach-Lee! Glad I didn't make a mistake clearing it by accident and it's working as designed.

The 12V power supply I have, I can set the voltage with a knob, and then check with a Multimeter to see what it's outputting and adjust as needed.

A few follow-up questions:

1. Do I need to disconnect the car from the batter, and charge the battery directly, or should I use the connection points like when I was powering it externally with a power supply during updates?
2. What voltage should I set power supply to, I think I have it set to a fixed 13.65V output currently?
3. Do I need to check battery voltage after full charge to confirm it's full?
4. Any value in resetting the battery days again?
5. Am I overthinking this?

 

[Mach-Lee]

Always use the proper connection points for the power supply or charger (the ones on the fender). For overnight, turn it down a bit to 13.5V. That's really it.

The SoC when the BMS is reset is not critical, battery just needs to be mostly charged and it will figure it out exactly over the next week or two.

 

[SteveUk]

The 57% state of charge on your 12v battery is an indication that it is no longer holding anything like what it did at new. I would just keep checking that monthly for any substantial deterioration.

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