Originally Posted by rkswyo
A dumb question for you guys. Could you mount the inverter in a handy location and plug the shore power cord into it?
I think I know what you are asking.
You want to hook your camper's shore power cord through a 30->20 amp adapter and plug it into your inverter in order to power your 120 volt ac camper items off your battery; right?
Lets see how big an inverter you would need. 30 amps times 120 volts equals 3600 watts, No Problem! They make those!
Now how much battery bank do I need?
3600 watts divided by 10.5 volts (low battery cutout) = 350 amps
How long will the standard 75 amp hour battery last trying to deliver 350 amps? This is actually more complicated that it sounds.
From this graph you can see that the bigger the amp demand, the less capacity a battery has. Say for sake of argument your 75 amp hour battery was even capable of delivering 350 amps without melting (it can't BTW). And further it can somehow manage 25% of capacity at that draw (which it won't get that high). 25% of 75 AH equals 18.75 AH
How many hours will the 18.75 AH battery last trying to deliver 350 amps?
0.05 hours or about three and a half minutes.
We won't get into the converter trying to charge the battery with the battery.