Micro Microwave

[jeremyshaw]

Anyone tried one of these?
http://www.thewavebox.co.uk/

We've been thinking of a microwave on the boat for a while, but they are normally quite big and heavy, and the Sanyo 12v ones, though apparently good, are several times the price of a cheap counter top.

These come in at around £130, and I like the triple input option, so am tempted. But has anyone tried one for real?

Thanks

 

[Tidewaiter2]

No, but we were looking at 12v M/waves and these came up on a google search website, a piccy with a builder lifting one- they are actually pretty big- seemed about 2/3 jerry can size.
The Samsung Roadmate 12v appeared smaller, but Autohelm failure put it on hold for a season.

 

[jeremyshaw]

Yes, not that small, but only 6kg though, which was another attraction. Sanyo Roadmate is a bit bigger, but twice the weight. This job would be easier to store away...

 

[l'escargot]

Draws 20 amps and only gives 110w on 12v from a cigarette lighter socket.

 

[Tidewaiter2]

Yes, SWMBO, who is the Sparker, spotted that- we could only really use on S/pwr or with engine going. That plus cost back burnered it for us.
Probably Ok if you've got a site generator unit or a big Volvo 32ton reefer with sleeper cab, with it's batteries. Would beat a Roadchef or greasy spoon menu all week for sure; frozen SWMBO homemade stews and pasta sauces, local soss and bacon- Damn, I'm drooling.

 

[VicS]

110 watts will be useless. compare with the power output of your domestic m'wave.

Ours is 90watts for keeping things warm, 180 watts for defrosting but will just about keep some things simmering if it they have already been heated. 360watts is neither one thing nor the other. 600watts is fine for most things. 800 is its max output.

425 watts on shore power will just about be enough to reheat stuff that's already cooked provided you are not in a hurry.

Bear in mind the dangers of not fully re-heating food

 

[William_H]

The nature of the microwave operation is such that it makes very little difference if the box is big or small. The power is fed into the food in a fairly efficient way so to heat or cook a chicken requires the same watts by time regardless of how big the oven is.
So space on the bench is the only reason to buy a smaller one.

The power source is the question. Standard Microwave ovens that run on 240V AC are incredibly cheap. Many people run them on an inverter off the batteries usually charged by thhe engine at the same time. The total inefficiencies are horrible.

The AC from the alternator is rectified to DC and feeds the battery. The DC at high current goes to the inverter where it is converted to AC transformed to a higher voltage and then switched to become 240V AC. The 240V AC feeds the microwave oven where it is transformed to 1000V AC then rectified to become DC to feed the magnetron.

The DC supplied microwave oven is more expensive purely because of low demand. Here the DC is converted to AC, rectified and feeds the magnetron avoiding several stages of conversion so are more efficient.

Perhaps an elegant solution would be a 240V alternator driven by the engine for use only when the engine is idling. Or go the whole hog and have a 240V AC installed generator.

There seems to be no easy solutiuon. olewill

 

[rogerdog]

Would have to say that the best solution if you really want a microwave on board would be an inverter and then you have a huge choice of domestic microwaves.

BUT only concider the invverter route if you have both a large battery bank and a high output method of recharge as the amount of power required is large, for example even at 600w with the inefficiencies of the microwave you will be using about 800W giving a current of about 67A - now no inverter is 100% efficient - so look for about a draw of 75A while the miocrowave is running. This is why a serious domestic battery bank will be needed to be able to use the microwave (not just get it to run)

In addition when choosing the inverter - don't just get an 800w version it won't start the microwave easily unless about a 50% overload capacity is built in to the inverter (often sold as 800 continuous and 1600 watts peak or simerlar) - it's all to do with the power factor of an applience - ie a resistive load (hating element etc will be a paer factor of 1 -inductive /capacitive loads (microwaves/ moters electronic bits) will not five such an easy to drive load.

The last point - the inverter probably will need to be sine wave as the electronics and motor on some domestic microwaves does not like a "modified sinewave" output as described by many of the cheaper inverters (it's not midified sine - it's a square wave with rounded corners!)


Sorry about the long post - but quite a few points needed.

Oops missed the point above -or go genset etc (DO make sure generator is suitable for 'electronic items' as some are not due to poor regulation etc and get it installed coreectly - just because its slef generated does not make it less letal if incoreecly installed then "real" mains.

 

[jeremyshaw]

Many thanks for all the comments.

I agree the low-amp DC input on this machine is pretty useless, but the 'direct to battery' and AC inputs give it good flexibility. The thing we particularly like is the size and weight as we want something we can stow away, then get out when we are hanging around a place for a while.

So we'll order one and give it a go. I shall report back in due course.

Thanks again for the contributions.

 

[Searush]

Yeah, I was looking at a reasonably powerful 12v microwave





. . . . until I saw it was taking 65Amps off the battery.

 

[dsw]

i got one thinking i could make milky coffees and tv diners ect but crap yes total waste of money unless you like to have your engine running well above tic over when cooking that seams to take for ever to get hot, so back to the good old gas cooker for me .