Installing Extra batteries in a KW W900?

I did exactly what you describe and it works great. I put in a battery isolator between the two banks, that allows both to be charged when the truck is running. The passenger side runs the inverter, truck off, powering the hotel loads for 11-15 hrs without using any power from the starting batterys.

 

I did the same, I used 4 deep cycle batteries for all sleeper items including the fridge.I had an Isolator that allowed you to connect both banks of batteries if for some reason the start batteries had gotten run down. Also i had a large 3500 watt inverter that had a built in charger so that if had access to shore power I could plug in and keep all 8 batteries charged. And run all items off of shore power instead of the batteries. I ran this setup for 2 years before I added an Apu for the Hvac reasons.

 

it's done alot, no biggy. Only thing i would mention is that your W900 is already rather heavy and four more batteries isn't going to help

 

Wouldn't four batteries be lighter than an APU?

 

probably but just four batteries doesnt give you heat, ac and block heater without other equipment. id say ots a wash weight wise by the time you add all that, but cheaper

 

So how many hours are you getting on the 4 battery bank before recharge?

...using a microwave, refridgerator and TV?

Since cranking amps isn't a concern, would deep cycle marine batteries be better?

 

Yes, use deep cycle. I always left truck running while using microwave. Probably didn't need to, just felt like it pulled alot. Use an inverter that you can set the low voltage cutout and you will know when you need to crank up the truck to recharge the batteries. With the isolator you can set it lower than you normally would if they were the start batteries. I could watch TV use other accesories etc, on a regular break without idling. 34 hour break I would get a motel.