Originally Posted by Iggy
I was just wondering when you are ready to tow and your 5th wheel or TT are plugged into your truck will the truck charging circuit charge the trailer battery when driving?
Maybe but probably not much.
The reason is the distance (feet of wire) involved.
The problem is your truck engine battery is very close to the alternator
and it's internal voltage regulator.
The trailer battery(s) is/are several feet down stream.
Your engine battery gets a quick charge and the voltage peaks and the
voltage regulator drops back to a lower voltage.
The trailer battery does not get enough voltage to boost its charge much.
Some folks have run larger battery wire like 8 or even 6 gauge and it seems to help.
There are gismos that you can buy that boost 12v up to a charge voltage
of closer to 15 just for charging batteries while on the road but they're