Battery issue, Charging issue or BMS issue?

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Raptorbert

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So a while ago I noticed that my Auto stop start was no longer working. Took it to ford, they tested my battery and replaced it. Stating it failed a rotunda test. Fast forward today and i'm seeing the same issues. With the battery being only 2 months old I was reluctant to blame the battery but I started monitoring SOC and voltages like a hawk because the ford dealerships around me a horrid (they already said my voltage is "within normal spec.")

Here's a timeline:

Last night battery was at 76% after driving 1hr.

This morning battery is at 60% and 11.8V

Drive 15 min to orielly to test the battery, stop at their lot and im at 68% 12.1v

They test it, found good and recharge. their tester says 62%

Leave there, drive 15 min to Napa, check myself and it says battery is now 59% with 12.3v on the battery

They test it and report 52% SOC battery good an recharge.

Any idea what could be going on here? im at my limit with knowledge on this matter and wondering what the issue could be?


Also I do have a B162F trouble code. There's an SSM for it which dealership has performed at least 3 times which is to reprogram the BCMC module but it doesn't fix it. the B162F is a "VDM circuit open" message. Could this cause a drain or an issue charging?
 

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HighwaySentinel

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Subscribed. I am in a similar place as you. Come home after work (45-50mins) of driving and battery at 12.3. Check it the next morning and it is at 12 or 12.1. And it will get increasingly worse as the days go on. If I monitor the voltage on the dash, it will regularly drop to 12.5, then 12, then 11.5 while driving. It's almost as though something is telling the alternator not to work. If I drive with my headlights on, I don't have the alternator issue, but I will still lose around .2 volts overnight.
 
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Raptorbert

Raptorbert

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Subscribed. I am in a similar place as you. Come home after work (45-50mins) of driving and battery at 12.3. Check it the next morning and it is at 12 or 12.1. And it will get increasingly worse as the days go on. If I monitor the voltage on the dash, it will regularly drop to 12.5, then 12, then 11.5 while driving. It's almost as though something is telling the alternator not to work. If I drive with my headlights on, I don't have the alternator issue, but I will still lose around .2 volts overnight.
its seems to be all over the place as far as readings. I have yet to see a deep sleep issue or anything other than stop start not working but I do drive it daily.
could be the alternator. it may not be putting out thebpower needed to run the systems
it could, but I will say the voltage is almost always 14.5-15v on the dash while driving. Even over an hour of driving. if the alternator is having a performance issue would that result in a DTC?
 

The Car Stereo Company

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the alternators now days are complicated. with the bms and all the other crap connected, its no longer just "putting out power" now we got computers connected to alternators saying "when" to put out power. my guess would be something there. i dont think it would necessarily trigger a dtc though. @FordTechOne would have better knowledge of thi
 
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Raptorbert

Raptorbert

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OK thanks. Wish there was more diagnosing I could do on the matter since the dealership didn't really care to look at the issue.
 

FordTechOne

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You may be chasing a ghost. If there is a charging system fault there will be warning messages in the instrument cluster accompanied by DTCs. The charging system is module controlled; it regulates voltage based on load, operating conditions, and battery state of charge. Voltage will vary between 11.X and 14.5 as dictated by the charging strategy. 12.6V is a fully charged battery; it’s normal to see a reading below that after the truck has sat.
 
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