There are a couple well detailed threads in the TC University section on installing dedicated large wire circuits from the alternator to the T C batteries.
I would install 4AWG wire and a smart solenoid that separates thr TC and truck batteries or electrical systems to prevent the TC batteries from discharging back to the truck during high current demand situation conditions like night driving with the headlights, running lights, fan, and stereo all on. With the factory plug only, the alternator will never fully charge the TC batteries.
