The Coleman Niagara came from our dealer with a single 20 pound propane bottle and a Group 24, Marine Deep cycle 12 volt battery, all neatly concealed behind a ABS cover on the tounge. The easiest and cost effective way was to double up on everything.

The second propane bottle goes beside the first, behind the ABS cover. I just needed to get two of the J-bolts that hold it in place. the dealer wanted $10 for these, but in the meantime I used some 3/8" threaded rod from work, and bought some wing nuts with nylon inserts.

I decided not to get any form of automatic change over for the propane. When one gets empty, I will manually switch over to the other one. I'll see how much of a hassle this is before deciding on investing on anything futher. ( I have since found out that I then have to re-light the fridge and water heater when the bottle runs empty, so an auto change over is on the list)

 

I bought a second group 24 battery, and a battery box for $72.

I thought about getting a bigger battery, a 27 or even a 31, but was concerned about all the extra weight. Another problem was the bigger size.

I had some 1 1/4" angle iron I cut to size, and welded to the frame, and painted black.

I am currently set up with them wired in parallel, giving me 12 volts but doubling my Amp hours from 85 to 170. I know this means they will both drain at the same rate, but this is better for extending the life of the batteries, instead of draining one before switching over to the other.

I got a digital volt meter so I can monitor the voltage as we camp.

I recently got a Deep Cycle battery charger. 2/10 amp, and re-charge both batteries when we return from camping.