Microwave off ehu (1 Viewer)

Wellington

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i know it’s not usual, and I know a lot people have no time for microwaves, but I find it incredibly useful. So I want to be able to operate mine off ehu, especially at overnight stops.

I favour an inverter, rather than a 12v microwave (because then I can use the coffee machine as well!) unless there is any reason to favour one over the other. Is there anything I should know (in words of one syllable please. I have only the dimmest awareness of what elecktrickery actually does!)

I am planning to drive to an aire or similar, park up, heat up a previously prepared meal for my child (takes one minute, max) and turn in. In the morning, I will run the coffee maker, heat milk for my coffee (again, two mins) and drive off again. I’m not expecting to wild camp for days. We have a solar panel and two leisure batteries, and there will be the usual occasional toilet/water pump and fridge use.

Is this at all feasible? I know most people are happy with gas, but with a small child, cooking meals at home and freezing them for later zapping is fast, convenient, nutritious and minimises washing up. Also, I have found no way of reheating a baked potato on a gas hob, and my daughter practically lives on them! When we’re in the van, I’m on holiday, and I want the most convenient option for me.

Do I need to worry about the batteries? I keep reading about not discharging them more than halfway, is there any sort of safeguard to prevent this happening? Is it worth upgrading to lithium batteries as well? Can anyone recommend a resource for learning about invertors for dummies?
 

Riverbankannie

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Sounds feasible to me. I’m sure there are plenty on her who do just that with no problems. Hopefully so,done will be along soon.
 
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TheBig1

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There are hob-top "ovens" available that will easily re-heat a jacket spud etc from frozen. The gas hob heats a glorified saucepan with a trivet inside and a lid to contain the heat.
 
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funflair

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I wouldn’t be without the inverter and thereby microwave, coffee machine, charging anything I want etc etc, you will need decent batteries otherwise the voltage will drop too low and trip the inverter, we ran fine for a few years with just two batteries but we are now on four 80ah Gel. The inverter needs to be wired to the batteries with heavy duty cable.

Martin

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Kannon Fodda

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Choose a low power microwave if it's 240V. On startup the unit can pull twice the rated cooking power so a standard 800W microwave would need an inverter of some 1600W plus headroom, say 2000W rating. That's also then going to need some meaty cables between the batteries and inverter. Also at those larger powers, even if you do have EHU, you could be overloading the hook up rating and tripping it out.

A 12V microwave might be expensive, and will take a lot of current from the batteries so you'll need some beefy cables between microwave and batteries. Probably a challenge.
 
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In words of one syllable, there's about enough energy in two batteries to run a microwave or coffee machine for about an hour.

You can skip this bit. Two 100 amp-hour batteries at 12 volts will supply 100 amp-hours before they are down to the 50% level. Since watt-hours = amp-hours x volts, that's 100 x 12 = 1200 watt-hours. That's 1200 watts for 1 hour.

If you stick to the times you describe, ie keep your total usage of the microwave and coffee machine to about twenty minutes, you should be fine.

My view on microwaves is that all the things that make them quick and convenient in the home kitchen apply ten times more when camping. I wouldn't be without one.

There are two kinds of inverters, pure sine wave (PSW) and modified sine wave (MSW). Modified sine wave is sometimes called quasi-sine wave. Pure sine wave is a nice smooth wave like standard mains electricity. Modified sine wave is a more or less jagged and sharp wave that is cheaper and easier to produce and is perfectly fine for heaters, electric drills and many appliances, but causes problems for many complex devices with electronic controls inside them.

I had an MSW inverter that made a microwave run at low power, and simply would not run the coffee machine at all, even though it was powerful enough.

So I'd suggest you get a 1500 watt Pure Sine Wave inverter. And maybe look at getting a third battery if there's room.
 
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TheBig1

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I find it interesting whenever anyone asks a straightforward question there are some that ignore the actual question or poo poo the idea. Takes all sorts I suppose.
I wasn't poo pooing the idea, just offering another cheap option. We carry a small microwave and have an inverter, but sometimes other options work as well
 
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Wellington

Wellington

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Thank you autorouter, that is very clear and easy to follow, and I now have a much better idea of what I need to look at in terms of battery capacity and so on. It’s sounds as though I will have plenty of capacity to do what I need, with a suitable inverter.

I am planning to look at getting a combi oven, so that I can use the microwave off hook up and have an oven if when we hook up, and can also select microwave wattage as appropriate.

I know it isn’t for everyone, and it’s a lot of faff and expense. For us, I am the only person to do All The Chores. All the driving, navigating, finding places to stop, set up, cooking, washing up, toilets, water, running after bikes, wrestling with bedtimes - it all falls to me, and it can weigh
quite heavily. I find it especially irksome when I am supposed to be 'on holiday' so anything can save on washing up or a make dinner appear faster is worth quite a lot of faff, for me personally.

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Wellington

Wellington

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I find it interesting whenever anyone asks a straightforward question there are some that ignore the actual question or poo poo the idea. Takes all sorts I suppose.

It’s very common (on forums especially) and it isn’t without value. When posing a problem, people will often present their current idea of a solution to the problem, rather than the actual problem itself, so it isn’t necessarily unhelpful to have people disregard your current solution and present an alternative. It can sometimes be frustrating, for both sides, because the problem has generally been insufficiently explained and the parameters or limitations not fully understood by one or both parties. Different perspectives are always helpful, I find, and are one of the great things about the hive mind on the internet.
 
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pappajohn

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Don't be fooled by the words '12v microwave' there's no such thing as a 12v microwave.
It contains an inverter to step up to 230v so will still hammer your batteries for a short while.
 
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When I do baked potato I boil it in a saucepan first for 15 minutes then it only needs half the time in the oven to crisp it up.
Personally I think your just creating hassle and expense for yourself... Just my opinion. :)

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funflair

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When I do baked potato I boil it in a saucepan first for 15 minutes then it only needs half the time in the oven to crisp it up.
Personally I think your just creating hassle and expense for yourself... Just my opinion. :)
Expense undoubtably, bit for the convenience you have to pay, 1 minute for savoury rice,two minutes for hot milk for a latte, 30 seconds for Nespresso coffee none of these are a big ask of most batteries and I guess to some of us the cost is justified.

Martin
 
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DBK

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As @autorouter has said what you want is quite doable. :) I fitted my own 1500W PSW inverter and it probably cost a little over £200. But I fitted a cheap one and for something from a well known make you could double that and more plus of course the cost of fitting if you are not going to fit it yourself, which I wouldn't recommend unless you are comfortable working with potentially lethal voltages and fire-starting currents. :) I can only suggest getting a few quotes then decide based on the options but my guess is something around £600 to £800 upwards plus the microwave of course.

As a complete aside your remark about driving to an aire, eating a quick meal then turning sounds like a nightmare! :) We like to stop no later than around 14:00 then after a late lunch explore the surrounding area on foot.

But we do have an oven, a gas one by SMEV which wouldn't cut the mustard on Masterchef but it does the job. I've just eaten lunch which was salad plus two supermarket quiches warmed up in the oven. If you have room for an oven it might be an option. I think they could be used on the move but a roast potato might roll around a bit on corners. :)
 
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The microwave in our MH is marked 800W. However thats the power put into the food, the power taken from the mains is 1250W.
When I designed my inverter systemi orginally thought a 1000W would power my wife's 800W hair dryer and our 800W travel kettle, but realised that by installing a 1500W inverter we could run all are appliances should we need.
Of course we can only run one thing at a time, but they all need to be run for only a short time the batteries can easily cope.
After five years all is still working well. Note the microwave manufacturer recommended a pure sine inverter.
 
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This is what I'd fit.. .

Scrap your old batteries, buy 4 new Varta Lfd90 batteries. £400

1 new nasa BM2 Battery monitor £130

1 new 2000w Studer psw inverter £1600

Heavy duty cable, isolator, 2 way changeover switch, clips etc £100.

Presuming your solar is ok that's about it (y)

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hilldweller

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We love our microwave
and they are brilliant

Just to balance the views, when we got a Swift, the first thing I did was rip out the microwave and turn the huge space into a good kitchen cupboard. Decent weight saving. It does have a very good cooker which serves our needs without hammering the batteries.

Gas does a magnificent job of generating heat and packs vast heat into a small space.
 
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Stonemags76

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I understand the need for a microwave, especially with a child, but have you thought of freezing in boil in the bag reusable bags? Think you could easily reheat on the hob and leave the microwave for use on site?
 
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DBK

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@Wellington I hope you are not being put off by what I will politely call the "banter" on this Thread. I might suggest a lot of it stems from folk not having properly read your question which stated you wanted to run a microwave for one minute to warm-up a pre-cooked dish.

A microwave consuming 1500W will draw around 125 amps from the batteries which is why you need thick cables. But running this load for just one minute works out at 2 amp hours (Ah) which is negligible. In reality because of the high current it means more than this if you want to check if your batteries are up to it but even saying it equates to 10Ah it is nothing to worry about. But warming things up is probably the best you can expect. If you want to cook things then you may need more batteries but you won't know until you try. :)

Ideally the microwave needs to be close to the inverter, but it doesn't have to be. Mine is 2m away so I just have thicker cables to compensate. :)
 
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hilldweller

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for just one minute[

No-one seems to have picked up on this. My morning ritual is to put a mug of cold milk into the microwave for 1:11. It comes out tepid. Then it drenches 3 Wheatabix for a hearty breakfast. Except on the odd day when it drenches Alpen for an equally hearty breakfast.

So is that 1 min viable ? Most ready meals take considerably longer. And all of a sudden the nice simple plan turns to brexit.

But easily solved, buy a generator.

[ NB that last sentence falls into the banter category even though it is a feasible solution ]
 
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Duck Truck

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I love the fact that we are all different because if we all liked the same thing life would be very very boring

If you want a microwave and can afford the installation costs
GET ONE

If someone said No gas oven and they wanted one same reply.
If the van will take it and you can afford it, Listen to others points of view make your mind up and do it
 
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