# Inverters & Microwave ovens



## Jean-Luc (Jul 21, 2005)

I have just fitted a microwave to my MH and plan to uprate my 400 watt inverter to a 1,500 watt, or higher, unit to support it.

BUT, I have just read in the Q&A section of the Maplin site that their inverters do not support powering a microwave oven :? 
Is there a problem with trying to power a microwave oven with inverter power, is it to do with the quasi sine wave, do you need a pure sine wave perhaps.
Over to you guys 'in the know'


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## ched999uk (Jan 31, 2011)

I believe the main issue is a microwaves massive startup current consumption. For example an 800 watt microwave is 800watts of microwave power not the power consumed. A microwave may pull upto 4 x the continuous power on startup. So a 800watt microwave might need 3200 watt inverter.

That said I am sure people on here have real world experience of using microwaves on inverters.
Hopefully they will reply.


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## JeanLuc (Jan 13, 2007)

You might find this paper useful - by Charles Sterling, MD of Sterling Power Products.
http://www.sterling-power.com/products-230vi-pure-info.htm

In it, he explains that some modified wave inverters will not run microwaves, but in the datasheets for his latest Pro Power Q range of Quasi-Sine wave inverters, he claims they will run many microwave ovens - but not all.
http://www.sterling-power.com/products-230vi-quasi.htm

Generally, brands like Sterling are very good and probably better than those sold by Maplins - I guess you get what you pay for.


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## raynipper (Aug 4, 2008)

My 1800 watt inverter struggles to power my 800 watt microwave. It does it but you can hear the microwave humming seriously.

Don't know offhand if it's a pure sine wave or not.

Ray.


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## ggicollegepunjab (Mar 15, 2012)

of course microwave starting current load is more than inverter 1500VA output. You have to increase inverter output current up to 2000VA to get good results.


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## Sprinta (Sep 15, 2010)

my microwave is 800watt but has an initial sub-1200watt startup and so my first 1000watt inverter wouldn't run it. I've changed to a 2kw Ring inverter and all is well. We don't use it for much more than warming soups and beans and suchlike, and so aren't draining the batteries for more than 5 or 6 minutes at a time (not only that but it tends to cut out the TV, grrrr) It shows that the batteries (170ah) are being drained down to 11.48v while operating.


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## Jean-Luc (Jul 21, 2005)

THIS is the model I have got, it's a 'low wattage' leisure product, while it's rated at 700W output its power consumption is marked as 1200watt.
I cant find any reference to a higher spike demand at start-up, is this something which is engineered out for leisure versions.
Is there anybody out there successfully using a leisure specification unit with an inverter.


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## Sprinta (Sep 15, 2010)

what do you mean by 'leisure' specification, like I said, mine is a cheap (£30ish) type 800w unit we got from Tesco and works on a 2kw inverter


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## speedytincan (Dec 22, 2005)

We have a cheapy 240v micro/grill rated at 800w with a power of consumption 1500w, when not on hookup its run through a Sterling 2500kw guasi sine wave combi/charger/inverter, seems to cope with the demand, never given us a problem, although putting the toaster on at the same time was asking a bit to much.


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## Sloany (May 15, 2010)

Hi, I run my 800w micro off a sterling 2000w inverter with no problems at all. 

Dave


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## Bill_H (Feb 18, 2011)

I've a small Dawoo QT microwave rated at 600W with a stasrt up power requirement of 1000W.
I don't run through an inverter, but my Honda EU10i (rated at 900W continuous with a 1000W surge) runs it without any problem.


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