Inverter Powered Microwave in your Caravan / Camper

I haven't done it but it could be possible. You just need to bear in mind that your Microwave may say 750 or 900 watt but that is only the output wattage. The input could be as high as 1500 watts which would probably be too high for the 1500 watt inverter. (check the back of the microwave to see what it draws)

To run it at say 1500 watts at 240 volts would require around 115 amps from the battery to supply the 1500 watts at 12 volts. That doesn't take into account any losses in the system which can be considerable depending on the efficiency of the inverter.

Hi acd, fairly sure I have seen this topic covered onsite before: try looking up some of the good blogs such as: ( search terms..) electricity for camping , battery power, inverters etc.. MG.

Try asking the question here

http://www.caravanersforum.com/

We have a 240v microwave in our caravan...........from memory it is a 1000w but might be 1200

I have a 1500w inverter and it runs it easily.........having said that I don't believe the heat is as efficient when compared to it running on 240v...but we never use it for cooking......only reheat a quick meal or snack ...so probably maximum run time has been perhaps 10 mins at a time

our power system is 3x105ah deep cycles..........the power consumed is minimal and shouldn't affect a well balanced system a s the time frame in our case is still minimal use...and only used for convenience at times

if that's any help

We have a 240 volt microwave..1800 watt inverter..6 solar panels and 4 deep cycle batteries. I hardly ever use the microwave..the evening from meat/dinner gets defrosted on the engine tappet cover over a beer or 2 when we pull up and I had forgotten to take the food from the freezer at lunchtime.

Anthony,
We are currently building up a 4wd truck based expedition vehicle and I am not having gas. Everything will either be diesel fuelled or electric. The inside cooking will be done on an induction hotplate, with toaster and microwave. As a part of the planning I did lots of testing of various appliances to size my system needs.

In regards to the microwave I am going to use a small unit that we have from when we sold our weekend cottage. It is labelled as being 1200w and when I run it my power monitor tells me it is pulling just on 1000w. It pulls quite a bit more when starting but any good inverter will normally have a surge capability twice its rated output. Only use a quality true sine wave as too many appliances will not work well on modified or square wave.

I measured the current draw for the 1000w Projecta inverter that I used for the test and got about 85amp. My test mimicked the morning heating of my wife's hot chocolate which takes just on 5 mins to boil the big mug of milk. So this equates to about 7AH used. You can scale from this as to the battery capacity you need. Just remember to never take a wet cell, AGM or any lead/acid style battery below 50% SOC if you want good life.

I have Lithium batteries which is a totally different story but not relevant here.

Hope this helps.

'Morning Anthony,

My van came with an 1800W Xantrex pure sine wave inverter and an 800W (output) Sharp Carousel MW oven. The specs say that the MW needs 1200W input.

We don't "cook a meal" with the MW, but frequently use it to reheat left-overs and defrost when we forget to organise that in advance (although, like Wholehog, we often defrost on a hot engine after a day's driving :-)).

At full output the MW pulls 130 amps according to both the inverter control panel and the battery monitor.

I used to have 315Ah of AGM, now have 360Ah of lithium batteries. 200W of solar on the roof and 240W of portable panels. I charge from the vehicle with a 25 amp dc-dc charger. The system worked/works on both battery types, but is far better on lithium. But as Alastair D said, that's another topic.

Cheers

Anthony,
In my install I have a big inverter which is fed by 0BS cable. For your system I would go no smaller than 4BS to make sure that the voltage losses are minimised. One big difference between Lithium and Lead/acid is that the voltage for Lithium stays quite constant during discharge until just before reaching full discharge. As you would know for lead the voltage drops progressively and you need to save every millivolt to get the best value from your batteries. The size depends a lot on the cable length too so the rule is - as short as possible and as big as you can afford.

As a guide if you pull 100A through a 5m length of 4BS cable you will lose just over 0.4v and dissipate approx. 50w in the cable. This energy is better used in your inverter and by going to 2BS you would halve these numbers. If you can keep the cable short then 4BS will be ok.

Hi Anthony,

Long time no hear from, though we hope all is well with you.

We gave some thought to your post and on our last trip bought a small microwave to run off an inverter.

SOOOOOOO glad we were not relying on it.

We have a 700w microwave and a 1000w (2000w peak) inverter.

The microwave would start, though would not continue to run.

Maybe we need a larger inverter to ride over the initial start up where the oven needs (an indicated) 1100w.

Maybe someone can let us know why our set up doesn't work.

All good for learning :-)

Cheers,
Wayne & Sally.