2nd battery

The water pump may be a "significant" drain but it is only on for very brief periods of time. They typically draw 5 - 6 amps {but that's per hour}. A 10 minute shower is about 1 amp. You will run out of water waaaay before you drain your batteries.

:C

Note on moving out slides while dry-camping. When we pull up to our site we leave the engine running while moving the slides out so as to minimize battery drain.

Also the water pump is a significant drain. I don't have numbers but you can see the amperage drain is significant by how much the lights dim (voltage drop). We will often run the gen to charge the batteries and at the same time take a shower and run the pump.

Cold weather dry camping we will run the gen at night and turn up the heat to 70F and then turn it down to 50F or 55F at quiet time. Overall we rarely discharge our 2 agms to 50%.

Always have two batteries. It is utter nonsense that Thor would be so cheap as to just install one. As noted two golf cart {6 volt}, batteries are a good choice "if" you have enough room. They are taller and often you will not have enough clearance for the batteries and if they fit there is no room to check/fill them as needed.

Two 12 volt batteries is what most folks have and they work well and can be replaced just about anywhere {replaced my two GP 27's with new Interstates from Batteries + for $100 a piece}. Most RV's don't need a lot of DC power, lights and the water pump draw very little. Slides and the furnace fan {the largest draw in any rig}, can both suck down your available capacity.

Having just one battery is simply a problem waiting to happen, think when - not if.

:C

crasster wrote:
I'd do 2 6V golf cart batteries in series for 12V. They are made for brutal charging/discharging and also seem to last for a good long while. You don't HAVE to add anything though, you'll just have less longevity if you are dry camping. If you only need lights, it should be no problem. 12V to the fridge, PROBLEM (4 batts suggested for overnight).

To be more specific, 12V for the fridge is a problem with one battery if the fridge is a three-way fridge running on 12V power. More common these days are two-way fridges that run on either 120V power or propane, and generally these require a tiny bit of 12V power for the control circuitry and would be fine with a single battery for a night or two at least. (A three way fridge on propane will likewise not need much 12V power.)

Usually the three way fridges don't have as much cooling capacity on 12V power as they do on propane or 120V power as the 12V heating element is undersized.

I'd do 2 6V golf cart batteries in series for 12V. They are made for brutal charging/discharging and also seem to last for a good long while. You don't HAVE to add anything though, you'll just have less longevity if you are dry camping. If you only need lights, it should be no problem. 12V to the fridge, PROBLEM (4 batts suggested for overnight).

If you have room for a second battery add it .. only cost $60 and whether you dry camp or not "SH+T Happens" and you will be very happy you had the reserve.

It never hurts adding a second battery if you have the space for it, RoyB outlined the usefulness of a second battery, but if you only drive from one power hookup to the next power hookup it isn't absolutely necessary. Go for it, in any case the added DC reserves may prove handy down the road.

I added 4 - 6V to mine and LOVE it. No power issues for a couple nights in the winter or a week or two in the summer without recharging. If you usually plug in then just get a Group 31 and you will be fine with the one and using it during the day between campgrounds.

On the other hand if you want to run your propane furnace for two nights when camping in an off-grid place keep in mind a single battery may not have enough capacity to keep going for the two nights with out shore power...

The rule of thumb for the propane Furnace blower fan is one battery per night of operation... Some of them will draw 6-7AMPS of DC current...

Also if you have a slide out on your unit the second battery really helps out moving your room slides in and out...

Roy Ken



Roy Ken

Do you dry camp? Do you primarily camp where you have access to 110v power? If the answers are No, Yes then don't bother.