micowave & inverter

G'day

1 - Not sure - someone else can answer that one .

2 - Has to be big enough to cover the initial high current draw from the Microwave - check the spec sheet - possibly 2 - 3 times the power rating !!

Cheers

Steve

The input rating is what you need to know.

This should be on a plate somewhere on the Microwave. It will probably give the Amps draw. Multiply that by 240 and you'll have watts.

A lot of the microwaves draw in excess of 1200 watts even though their output is 750 or 800.

This site says it is OK to run a microwave with a modified sine wave inverter.

Inverter info

Thats going to be a big and expensive inverter.

Honky

You will need between 80 and 90 amps to run this appliance. To put it in perspective, about the equivalent of a 4X4 starter motor.

So you will require a very big battery and big wiring (and only a short distance from the battery) to run this.

Cheers

Hi
As others have said ,microwave current demand can be very high[80+++amps]
You would need very heavy cables from batteries to the inverter
The 12v cable run would need to very short
The load on the batteries if using max power would be very high
Deep cycle batteries do not take kindly to high current use [shorten life}
You would need something like 500 amp hrs+++battery capacity.
3hrs of use @ max output would take the battery bank down the max recommended state of discharge.
How do you intend to recharge?

Any form of heating from battery power is not very practical.!

Peter

Hi Taswegian

You can but there will be a couple of drawbacks because of the shape of the driving voltage.

The unit will put out around 600 watts and it will sound noisier than standard and may vibrate annoyingly.

A 1500w unit is required (cheap) - but if u use a sinewave inverter (expensive)you will only need 1200w and won't have the other issues.

I run a similar microwave off a 1500w Pure Sinewave inverter in a boat. I have the engines running when I start the Microwave and then turn them off, works fine. My inverter is a quality marine job, however it is rated at 1500 watts. The cables to and from the inverter are identical to the thick variety you see on quality jumper leads. I presume the Microwave is already in the van.? My microwave is a small one and is not an oven, I think the rated power consumption is around 700w.

Taswegian,

From memory there is a 12 v microvave oven available from the '12 volt shop' at Parramatta Road Auiburn NSW phone 02 9748 1199.
Specs I'm unsure of but worth a call. Asfar as power consumption is concerned you would only run it for a minute or two too heatup something wouldn't you??

Regards.................................jeff

I agree largely with what's been said already.

....a very big battery....
Not necessarily.

Considering conversion loss, wire loss, power factor, and possibly additional losses caused by the non sinusoidal waveform, a 100A current draw could be expected.
Inrush current, depending on type of microwave could be double this figure.
But inverters have a burst rating, which may or may not allow for this.
I'm guessing, but a 1500W continuous duty inverter should have you covered.

Your average 100Ah AGM battery can supply 100A for about 33 minutes.

So you'd be looking at recharging this battery after ~26 minutes of microwaving (based on 80% DOD).
Note that the inverter needs to function down to an input voltage of 9.5V for this (this includes 0.5V drop in the wires).
If the inverter undervolts earlier, you won't be able to discharge the battery below 70% or so.
In this case you can expect your battery to last for ~23 minutes of microwaving.

cheers, Peter

Here is another possibility

Ebay page for portable microwave

Looks like it would work okay on low power, just be careful on high power setting.

Why dont youo run it off a small genny? I reckon that would make more sense, not involve such high amps and LARGE cables and you'd only need run the genny whilst the MW was running and that couldnt be more than 20 mins or so a day I would say?

Get some sticks and some matches and build a fire. Heat/cook your dinner on that. Or alternatively throw the microwave onto the fire and watch it burn. Its very funny.
Seriously tho, the above posts are correct i.e. microwaves typically draw around twice their rated output. Thus an 800 microwave draws about 1600w. You would need an inverter at least this big. Taking into account puekerts law, invertor losses (about 10%) etc. your microwave could see a 100 A/H battery depleted in less than twenty minutes.