Hi all , my inverter in my RW doesnt seem to be charging correctly , when the battries are down to about 50% (11.9-12v) if i plug the trailer in in only goes up to 13.5v , from what ive read bulk charging should be over 14v , am i assuming correctly ? what should i check first ? any other ideas ? i have 2 trojan 6v and 2 interstate 6v batts , thanks .. Dennis