[Bob86ZZ4]

I have two 12v deep cycle house batteries. I have 3 12v cranking batteries for the truck chassis. The cranking batteries also start the generator. I have a large rotary switch that allows me to use the house batteries for house 12v stuff. Or I can switch it to use the cranking batteries for the house stuff. Or I can set it to tie all 5 batteries together. I think this is the best system for you to use. The key here is that you can use your deep cycles without worrying about having cranking power. Then, when you start the engine for whatever just turn the switch to charge up all your batteries. Don't worry about remembering to set the switch. You'll remember. Otherwise if you don't have the switch how were you going to charge up the house batteries?

Now, I'd also advise you consider 4 or 6 6volt deep cycle golf cart batteries. My old class A motorhome had 4 x 6volt deep cycle golf cart batteries for the house power. You wire up two batteries in series and the other two in series, and then both pair in parrellel for a final voltage of 12v. This will give you tons of house power reliably. Then to top it all off put a couple large solar panels up top. My class A had three huge ones. It was great! Never a worry about house power with that coach. I would have liked to remove those solar panels and put them on my new coach if it wouldn't have been so much trouble. I left it all as it was and the buyer is very happy to have such a system. That coach also had an emergency relay that had a momentary contact switch I could push to use the house batts for cranking if for some reason the cranking batt was dead. I think that rig had a relay that engaged when the engine was running to tie all the house batts together and charge them from the alternator. It was a constant duty one, I know because it failed so I had to replace it for about $40. But, it was probably original equipment, 15 years old.

If you don't have something like this then every time you run your house batts down you'll have to start the generator or find shore power to charge them back up. Much better to be able to fill those house batts from the truck engine if you happened to be running that motor for some reason. If you don't have a need to start the truck then for sure just use the generator or shore power. But those solar panels are great, but expensive.