Inverter to run microwave and elec heater what size?

[bettyford]

I don't know what size to get to run a small Microwave and small electric heater.
I will be running it off 1 Marine Battery maybe I will need to add another one?

I can cut a hole in the roof but when it comes to electrical I'm lost.

Help

Thx
Ron

[daveb]

Depends on total wattage Ron. If the microwave is about 650w I've found that they actually take more to run it; maybe 800-1000w or more. If you plan to run a heater or a microwave off a battery you won't be able to run it for any reasonable length of time w/o the engine running and even then your alternator might not be able to keep up. Same with any heavy load. I can run mine for short times... 5-7 min w/o trouble as long as it's set to a lower power w/o the engine running. Even if I have the engine running, using the MW on high pulls more than what the alternator can supply and it still depletes the house battery. You can go longer if you have more battery power like 3 220ah batteries but those are heavy, costly and take up room. Also pulling real heavy loads off a smaller battery can do damage the battery itself, so I'd suggest a generator.
[edit] think about this, will a 1500 w hair dryer keep your van warm? There are some lower amp heaters but most are well over 1000w. Kinda why My Buddy sells so good.
Dave

[BrianW]

We have a ~700w microwave and run it off a 1500 watt inverter with no problems. I don't think I'd recommend running a microwave AND an electric heater at the same time in any event, unless you have a serious battery bank.

I can run our MW for 5-7 minutes on high without killing the batteries too much. Usually I run the engine, but sometimes I forget. We have three group 27 (I think) AGM batteries for a total of around 315ah.

[Ford_6L_E350]

Ron, as Brian says, you can run a microwave (or an electric heater) for several minutes without killing the batteries. That means you reheat something or make popcorn and not much else in a microwave. Or, you can run an electric heater for a few minutes.

Probably not what you wanted to hear. As Dave said, Mr. Buddy portable propane heaters are popular for a reason. Along with a Coleman portable stove and you are set.

Mike