battery drain?

[JWBFX4]

Well just to add a little to this.

I have had a good bit of electrical problems a while back (not on truck) and after talking and researching a lot about batteries, everything says that 12.6v is a fully charged battery. Anything above that is considered a "hot charge" Possible the 12.9 volts that your battery maintainer says is where it automatically kicks off to make sure it charged the battery enough

I was always told if the battery is atleast 12.2 volts its in good cranking range anything under that needs charging and if it in the low to mid 11's very possibly bad battery.