WHY Tow Vehicles don't recharge Trailer batteries quickly.

tl;dr and I'm a nerd that loves tech stuff. anyone have the executive summary?

I don't count on my tow to power (or charge) anything except the LED clearance lights and the brakes.

If I need more power, I start the generator and let it run in the bed of the truck, using an extension cord I installed under the trailer for the shore-power connection.