MICROWAVES?

Markd

Full Member

Messages
613
We had a digital one and never had an issue.... Only reason I changed it was it fell off the table it was on under 'spirited' cornering....

To be honest the only factual evidence of something being killed by mod sine wave I've come accross has been induction charged cordless toothbrushes....
I've just bought USB lead powered toothbrush charger for "standard" oral b brush.
 
Last edited:

Tezza33

Full Member

Messages
1,078
Available on Amazon
 

Caz

Full Member

Messages
397
When I used to caravan and nearly always had EHU, I carried a microwave in the caravan and used it a lot. A friend kindly gave me one, but the one at home blew up so that went in the house and I got a Tesco value one to use in the van. Think it was 700 watts. Never blew any trips.
 

Markd

Full Member

Messages
613
Personally I'd pay the extra tenner for peace of mind.
The key factor will be whether whatever you buy fits in the hole!
The supermarkets do very cheap microwaves and they seem as good as any if you just want basic (re)heating with the convenience of being on the doorstep.
 

r4dent

Full Member

Messages
66
800w micro good match to 2000w inverter but see above for comments about sin wave.

On a stand alone battery 130 amp
I assume you mean "130 amp hour" battery.
130 ah battery will give 65 ah before it is flattened, which is about an hour's worth of microwave use.

with its own 120 w solar system
In Liverpool in January the 120w solar will put about 6 ah a day back into the battery (5 mins use), in June this rises to about 60 ah a day.
You will get more if you move South and less if you move North. 800w appliance will use 65 amps, so about an hour before battery is flat.

A 1500w air dryer uses about twice the power.
 

Bobtaylor

Full Member

Messages
34
I’ve read all these posts with keen interest,
We plan on wiring in an inverter to power a microwave as we rarely if ever stay on sites with EHU.
I have the inverter, but although I have a reasonable knowledge of vehicle electrics, I don’t feel comfortable wiring in the inverter that will use the power that’s talked about, not knowing fuse sizes, cable sizes etc,
The problem is I’ve asked the local vehicle electrical place to give me a price, and he says he won’t touch any of the “Cheap” inverters available on the internet, of which I’ve bought....(about £50.....) he’s talking about spending £400-£500 pounds on one, plus installation
For that kind of money, I think we will do without a microwave.
 

Markd

Full Member

Messages
613
If you want to run a microwave you will want a fairly good quality inverter to deliver the power you need - 2kw roughly.
I'm afraid that a £50 inverter is unlikely to be either "man" or good enough.
I've seen one pitching 6kw peak but actually is only rated at 1kw continuous - even that would probably be marginal.
 
Last edited:

Landyseverywhere

Full Member

Messages
32
A bit away from original post but there's a bid on u tube of a guy testing psw vs MSW on a digital mwave heating water from memory MSW around 30% longer to achieve same temp...so if you use a MSW you will use around 30% more out of your batteries to achieve the same result as a MSW(and take around 30% more in time)..psw inverters tend to be better build quality than MSW and are not that much more in real terms may be an e tea £100 on a 3kwspread over the years of service,not a big difference and you can forget all the possible problems of MSW.I just bought 3kwconstant 6kw peak with good reputation among off grid solar users £215 inc delivery
 

Bobtaylor

Full Member

Messages
34
Not true , ours is fully digital
Hi Jeffmossy, hope you don’t mind me asking,
ive been planning for a while to fit an inverter into our new motorhome when we get it mid April,
It will be used to power a microwave, which as yet we haven’t bought,
ive got the inverter, eBay 6000w supposedly rated at 3000w continuous, and I’ve tried it on our microwave at home, 800w but it makes an unusual noise and doesn't heat anything.
ive just today tried it on my fathers simple basic 700w microwave, and again it makes a strange noise but doesn’t heat anything.....
can I ask what make of inverter you use, and the wattage of your microwave,
it will only be used via the inverter, as we rarely if ever stop on sites,
many thanks,
Bob..
 

jeffmossy

Rally Organiser

Messages
1,586
As said before not all modified sine inverters will work with a microwave and you also need LOTS of power , even then the microwave can take twice as long to heat up anything
 

Landyseverywhere

Full Member

Messages
32
How much did you pay for your inverter ? Price is a good guide to pure or mod sine wave !I have bought several off of eBay and returned them as not as described.I now have 2 one I. the van to run the microwave etc the other to use in my place in Spain 24/7 as it is off grid,can you post a photo of your inverter it may be one I have had in the past and returned
 

mistericeman

Full Member

Messages
181
We've used a 3000w/6000w Spannungswandler (German for inverter) mod sine wave one of these...

s-l300 (10).jpg

It's been fine for the last 4 years running toaster/kettle/slow cooker and cheapy 900w (input power) not cooking power microwave.
Weighs about the same as a small car.
 

Wooie1958

Full Member

Messages
892
As said before not all modified sine inverters will work with a microwave and you also need LOTS of power , even then the microwave can take twice as long to heat up anything

We have a Sterling Pro Power Q, 12v 1800 watt inverter running the inbuilt from new low power microwave .


If memory serves me right it`s 900 watt input and 550 watt output / cooking power and works much much better on the inverter than when we are on EHU.

It`s exactly the same for the wife`s 1200 watt hair dryer which is much much better on the inverter as well.

P.S.

160 watts of solar and 2 X 125AH Xplorer batteries.
 

Landyseverywhere

Full Member

Messages
32
Weight is usually the give away in my experience a300/6000 w should weigh around 6 kg upwards.Obviously a bit less just tends to mean ?lesser quality components(transformers etc) a lot less less components probably mod sine wave.Also worth being aware a microwave will probably be drawing 1 1/2 times its rated power so 800w at least 1200w so 5/6 amp @ 240v = 120A @ 12v + inefficiencies ..so check input cables and connections as well as battery capability
 

wildebus

Full Member

Messages
2,320
Hi Jeffmossy, hope you don’t mind me asking,
ive been planning for a while to fit an inverter into our new motorhome when we get it mid April,
It will be used to power a microwave, which as yet we haven’t bought,
ive got the inverter, eBay 6000w supposedly rated at 3000w continuous, and I’ve tried it on our microwave at home, 800w but it makes an unusual noise and doesn't heat anything.
ive just today tried it on my fathers simple basic 700w microwave, and again it makes a strange noise but doesn’t heat anything.....
can I ask what make of inverter you use, and the wattage of your microwave,
it will only be used via the inverter, as we rarely if ever stop on sites,
many thanks,
Bob..
There are lots of supposed "3000W" or "5000W" inverters that are hard pushed to provide 1000W.

But assuming the inverter genuinely can provide the quoted wattage that is not the end of the story. What Batteries are driving the Inverter? what cables are connected between the Batteries and the Inverter?

I was trying to think of an analogy to explain this and the best I can think of is this ....
Think of your setup as a car -
The Inverter is the Engine, providing the power. The more power you have the faster you can go.
The Battery Bank is the Fuel pump. The bigger the fuel pump is the more fuel can be sent to the Engine
The Cable is the fuel pipe. The larger the fuel pipe the more fuel it allows to be delivered to the Engine.

If you have a fuel pump designed for a 1000cc engine and you fit a 3500cc engine, it will not be able to run at full power as it is starved of fuel.​
If you upgrade the fuel pump but don't change the fuel pipe, that bigger pump still can't deliver the required fuel as it is restricted by the pipe​
If you upgrade the pipe but don't change the pump, it will not allow any more fuel to be delivered as the limit is the pump.​
I am just saying the above and may be pointing out the obvious, but it is incredible how many folk buy these massive inverters but don't seem to realise that the energy to drive them has to come from somewhere!
 

wildebus

Full Member

Messages
2,320
Weight is usually the give away in my experience a300/6000 w should weigh around 6 kg upwards.Obviously a bit less just tends to mean ?lesser quality components(transformers etc) a lot less less components probably mod sine wave.Also worth being aware a microwave will probably be drawing 1 1/2 times its rated power so 800w at least 1200w so 5/6 amp @ 240v = 120A @ 12v + inefficiencies ..so check input cables and connections as well as battery capability
Interesting comment ref weight and I would agree weight being a fair indication of ability. Just checked the info for my 2400W Inverter/Charger (the charger circuitry uses the same FETs, etc as the inverter so that won't add much extra) .... 19Kg (she is a big old beast and was fun to fit :D )
 
Top