Ford BMS Battery Monitoring System: How it Works, How to Properly Charge, How to Power Accessories

[jwoobs]

Someone at one point mentioned the battery gauge isn’t reading the battery itself, but the voltage the alternator is sending to the battery.

They are one and the same. In order for the alternator to top off the battery, it needs to raise the 12V system voltage above the battery's voltage. Once the battery is sufficiently charged, the alternator turns off and the battery is the only voltage source. At that point it drops back down to 13.5V-ish.

But when the alternator is running, everything that is connected to the 12V system is getting 15V.

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[lilfergy]

My question is it that the alternator is not sufficient enough to charge the battery on short runs driving 15-20 minutes. Or is it this new AGM batteries can’t keep a charge. What is powered on when bronco is off to drain the battery that much? Or is it a combination of the above?

If I drive my bronco to the airport, go on a two week vacation I will come back to a dead battery why? How much crap is on this vehicle to drain the battery that fast?
Can I disable some of it so it don’t drain the battery?

I have not even added any extra accessories to my Bronco yet, and it cannot sustain itself for a month!
So if I want a dash cam, I will have to plug my bronco into a charger every night?