not only these things, but if your batterys are DEAD and your converter is working hard to charge them, that coupled with the amps of the a/c , and extension cord (you ddint say how long or what gauge), could be the issue....your SINGLE 13.5 or 15k a/c unit should work fine on house a/c with proper gauge wire.....you cant run anything else on the circut in the trailer OR house though....A 13.5 a/c only pulls around 12amps running.......
2015 F350 Platinum Fx4 6.7 Diesel Dually. B&W turnover, B&W Companion, air bags and wireless controller.
2015 Heartland Road Warrior 420 Rt
2012 f250 Fx4 6.7 Diesel crew cab tinted n tuned
2012 lacrosse 318bhs touring- sold