Coachman Galleria - FitRV Video Review

[markopolo]

Divide the AC appliance wattage by 10 to get an idea of the DC amperage draw in a 12VDC system. Using 10 is a bit conservative but should allow for inefficiencies and losses etc. and give a good chance of success if you you size the wires and fusing etc. based on that.

If you have two typical RV type wet cell batteries then using a lower wattage appliance will have a better chance of success.

Examples:

700W / 10 = 70 amps. 4 gauge wire to a 1000 watt inverter could/should do it. With two wet cell batteries each battery would have to be able supply approx 35 amps sustained.

If that 700W appliance runs for 5 minutes then you use maybe 6ah of your battery capacity.

The chances of two typical RV type wet cell 12VDC batteries being able to supply enough power for a 1400 watt 120V AC appliance are much less. The gauge size of the wire would have to be double & same with the inverter. It would be difficult to predict the likelihood of success.

400 ah of AGM batteries with a 2000W or greater inverter should basically allow you to power any appliance that runs off a 15A 120V AC household outlet. It would not run an air conditioner for long (or possibly at all) as the batteries would be depleted relatively quickly.

[booster]

I would add a bit to Marko's analysis, based on what we have seen with our previous 260ah wet cell setup, and our current 440ah agm setup. With an adequate inverter, you will be able to run most anything in the van, we have tested that. The thing that might bite you is if the inverter you are using has a relatively high low voltage cutout (or low efficiency like some modified sine wave), or if you have wet cells that drop more voltage under load. We are setup to the very conservative side, and generally would not use batteries only to run a 100 amp load if we are under 50% SOC. We could do it, but would have to set the inverter low voltage cutoff lower than I prefer.