12 volt Microwave

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https://www.whispaire.co.uk/microwave1.html I use Whispaire Romsey if I need any assistance with gas or refrigeration very good man to deal with can overnight on the industrial estate where he is situated, just looking through his info and see that he has 12 volt microwaves and includes some important info with his description , thought it might interest someone ?
 
The theory is good, but in practice you would need to have a couple of pretty hefty cables from Battery to Microwave and the MW would have to happen to want to sit in just the right position within the camper (I can imagine the cost of the cabling being comparable to the cost of a 550W Microwave itself!)
 
Scotty said:
The microwaves come with the cables, been out for at least 15yrs.
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How long are they? and what size?
My Microwave location would need DC Cables of at least 25mm2 minimum with a length of 7-8Metres.
 
I never like a company that doesn't publish it's prices.
We publish ours and everyone undercuts us! well not all, but we often get price matched with sub standard versions.
Do I care? not in the slightest.
 
Those cables with the croc clips are not 100A rated! no way.
Sorry, I am just interested in the technicalities of the product.
 
I was looking at the published spec of the MW in the original post, where that quoted a current demand at the full selectable power of 100A (so a nominal 1200W).
Your Device is much lower power that that, so consequently draws much less current - and so can use cables with a lesser gauge.
(I am still a bit disappointed that there is no fuse protection apparent on the DC croc-clip cable? maybe it is not in the camera shot but there should be something protecting against the end of the cable - with its exposed plug pins especially - shorting out if dropped or the device developing a fault on the input).
 
To be fair the reviews of the wavebox are pretty good
Obviously excluding those that plugged it into the cigar lighter socket and had issues.... Go figure.

Those that bothered to read them got the 'powerport' that hard wired to the, battery (sort of glorified Anderson socket)
And were pretty happy with it....

I looked into them when I was building the transit and wanting all electric cooking....
I ended up going for a small 240v one (takes longer than a larger one BUT basically uses the same power just in smaller bites)
As we already had a 3000w inverter.

Loved the microwave.... And the rest slow cooker/toaster/kettle...

Some Folks on forums were determined that it wouldn't work....

We were very happy with it for 5 years....

Handy bit of kit that im sure someone will be delighted to take of you and enjoy.
 
I think Microwaves are very handy - but needs to be used safely with right-sized cabling and correct protection.

And also the right sized inverters... I watched a youtube video just yesterday saying how a 800W Microwave could be run off a Jackery 1000 (which has a 1000W Inverter). Um, no it cannot. a 800W Microwave will draw about 1300W typically while running.

As Scotty says when discussing making baked potatoes ... (and Kirk then wishes he bought that extra Lithium Battery and got a bigger inverter ;) )
 
I just did a little test with my AC Microwave and found out something I was not aware of ...
A microwave works in the same way as an Induction Oven in the way it uses power.

I have a 800W Microwave - this draws around 1200W of AC Power - and when the inverter is taken into account, around 1500W and 125A out the battery.
If I set it to a lower power - I can choose in 20% increments from 20% to full - it still goes to the maximum power but cycles between full and very low to get the average, just like an Induction Hob works.

It might well be different depending on the type of Microwave though? mine is a digital one. A manual one with a dial control for power might just stay at the set power? (got that type in the house - think I will give it a go to check).
 
On the couple of m/waves I have been arsed to take any notice of, if you can lower the cooking power it's always been done by periods of on/off that vary in time according to the level you set.
 
St3v3 said:
On the couple of m/waves I have been arsed to take any notice of, if you can lower the cooking power it's always been done by periods of on/off that vary in time according to the level you set.
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I just tried the "manual" Microwave I have in the house - dial for power and dial for time, no display of any type - and yup, it also does the full/no power cycling just like the "fancy" one and just like every Induction Hob I have used.
Shame really as it could be a good way to have a single unit that you can run on full power when on EHU and lower constant power on inverter (which would be a little kinder on the battery)

While the microwave was out I thought I'd take a photo of the label on the back ...
1626253067376.png
So as can be seen this 700W Microwave (650W-700W depending on your voltage I guess) actually draws 1100-1150W of AC Power, so you need an inverter larger than that to run it

In terms of battery power, I took this photo of the Cerbo screen so you can see the power and current pulled (as it happens the DC load matches near exactly the Solar input, so the power and current bottom left relate directly to driving the inverter to power the Microwave shown on the top right).
1626253368092.png
so on a Multiplus 12/1600 (1300W) Inverter, to drive a 700W you need to provide around 1100W (1086W shown) and this is pulling 1333W from the battery.
I have a pretty healthy 12.6V at this draw so the current is *only* 106A. If you have all Lead Acid then the voltage would sag more and the current would be greater. If you had a Lithium Battery Bank that could deliver a current of 100A (many Lithiums cannot and you might need 2 or even more to do so) then the voltage would stay higher and the current less (an advantage of a good sized Lithium Bank over Lead Acid).
 
Still for some reason think the energy needed to heat something must be roughly equivalent no matter how you heat it. Maybe a bit simplistic but the old saying we used to use “if it gets hot it uses a lot” still holds true. Big solar panels and lithium batteries seem awfully complicated and expensive when you can just turn the oven on…. What was it Tommy Sopwith, the great engineer and aviation pioneer said? “simplicate and add lightness”. Am I showing my age…….
 
Tidewatcher said:
Still for some reason think the energy needed to heat something must be roughly equivalent no matter how you heat it. Maybe a bit simplistic but the old saying we used to use “if it gets hot it uses a lot” still holds true. Big solar panels and lithium batteries seem awfully complicated and expensive when you can just turn the oven on…. What was it Tommy Sopwith, the great engineer and aviation pioneer said? “simplicate and add lightness”. Am I showing my age…….
Click to expand...
showing your age? depends if you were there when he said it :D
 
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