Battery questions for boondocking

When you say "portable inverter set" are you talking about a "portable inverter generator" that burns gasoline to generate 120vAC power or an inverter that takes 12v battery power and converts it to 120vAC power. Results in a totally different answer to your question but it sounds like you are talking about a generator.

If it's a generator, a couple 6v deep cycle batteries and then run the generator in the afternoon for an hour or two to recharge them, should allow you near unlimited time away from shore power and should be plenty to run the furnace overnight. Just plug in the normal shore power cord and your onboard charger will take care of charging the batteries (don't use the 12v outlet on the generator, it's very low amperage (7-10amps vs 40-60amps) and it's unregulated). For 5-6 weekends per year, I wouldn't mess around with a solar system.

If it's an inverter, you really need to consider what you are using it for. 120vAC items tend to use a lot of power and a battery bank to support it will be pretty big if you are using a lot of power.

PS: Inverter Generators are a generator type that generates DC power and using a built in Inverter converts it to AC power. A traditional generator develops AC power as it's native output but requires the engine to run at a speed that corresponds to 60hz AC power. A couple of big advantages to inverter generators, they typically use high quality inverters that generate much cleaner AC power compared to old style generators and second, unlike old style generators, they can throttle back when loads are light to reduce fuel consumption and noise. The old style try to maintain an exact engine RPM that corresponds to 60hz...typically either 1800 or 3600rpm. Even with little demand, it takes more fuel to keep the RPM up, it makes a lot of noise running so fast and when you add a heavy load, the RPM sags resulting in poor quality power which can damage sensitive electronics.

Hi,

Yes, the furnace fan really goes through power fast.

I doubt that your present battery is a true deep cycle battery. More likely, it is a cross between an automotive (starting) battery and a deep cycle battery.

What I would do would be to:
- Install two (or four) deep cycle (golf cart) batteries in series (or series/parallel if you got four).
- I would also get a catalytic heater such as the Olympian Wave Heater and not bother with the RV furnace at all (keep in mind that this is a non vented heater so you should have an open window at night ... I use a cracked window and fully open vent).
- Look for other places that power is "wasted" such as incandescent light bulbs (replace with LED/s).
- Install solar panel(s) to keep the battery charged.
(note that not all of these items need to be done at once. Do one at a time if needed .... keeping in mind the planned end result so you don't have to tear out anything later)

With such a system, it is very likely that your trailer would never need to be plugged in (leaving today for 10 days of cool weather camping and won't be plugging in at all). However, putting together a system like this isn't cheap.

A lower cost/simple alternative (not the cheapest either, but one that works well for many folks), would be to purchase a quality (and quiet) generator (~$1000) and just recharge your battery as needed. Perhaps a combination of a generator, LED lights (if not already installed) and a good catalytic heater (~$300) would be the best solution for your needs????????

An even lower cost alternative would be to use your truck to recharge the battery (and/or have a second battery that you swap out).

Perhaps the least expensive alternative would be to forego the heater and just wear more clothes.

No doubt you will get plenty of other great suggestions.
Have fun camping.

A pair of 6V GOLF cart batteries will give you much more stored power and they can be discharged safely to a lower level. They are big and heavy tho so make sure you have room for a pair. I think optimas are designed for starting vehicles and aren't suited for your use. But the battery experts will speak up. The high end would a pair of Lithium or Silicon batteries and they cost a LOT more. Trojan golf cart GC2 batteries are somewhat better than Walmart/Costco but can be harder to find and pricey.

You have to see your power needs first. Longest trip , what else are you using in addtion to the heater. What do you use the inverter for? They really are inefficient. Once you do that you can see what type of batteries you need. Many like the golf cart batteries instead of 2 12 v ones. Tbh, i really dont boondock much. You can also get solar to recharge the battery while your off grid.