If you truly wish to fully charge it--168 hours would work.
To quickly charge from an alternator requires extraordinary measures.
Start with beefing up the charging path to #4 wire.
Next would be an external diode fastened to the alternator.
Or a DC to DC converter to boost charging voltage to 14.8. Place the unit as close to the "house" battery bank as is possible without it being in the same compartment.
oil8390 wrote:
sorry one more question, when the trailer is plugged into my truck, how long would it take for battery to charge while driving down the road?