Off grid microwave

[Burkey]

Apologies I’m aware I’ve posted similar in the past but getting desperate for advice
I’ve recently sourced two 700w microwaves but discovered they are inappropriate and do not deliver to their specifications. The one recommended in earlier posts are not now available so would really appreciate any advice please
Regards to all

 

[peterc10]

Can’t provide an accurate technical reply only that our local appliance engineer installed the goods and found them incompatible. Apparently the specs were totally wrong.

I doubt your local appliance engineer has any knowledge of using an inverter to convert 12v DC to 240v AC in a motorhome. Very different to domestic mains.

What is the size of the inverter (in Watts) you are using and the battery bank (in Ah) you are running it from? Also is the inverter a pure or modified sine wave model. That information will help us to give you advice.

 

[bigtwin]

You haven’t indicated it thus far but do you actually have an inverter?

Ian

 

[Hoovie]

I doubt your local appliance engineer has any knowledge of using an inverter to convert 12v DC to 240v AC in a motorhome. Very different to domestic mains.

What is the size of the inverter (in Watts) you are using and the battery bank (in Ah) you are running it from? Also is the inverter a pure or modified sine wave model. That will help us to give you advice.

That made me wonder .... "Can’t provide an accurate technical reply only that our local appliance engineer installed the goods and found them incompatible. Apparently the specs were totally wrong."
incompatible and specs wrong as he couldn't fit the 240V 3 pin plug into the 12V Socket?

 

[bigtwin]

That made me wonder .... "Can’t provide an accurate technical reply only that our local appliance engineer installed the goods and found them incompatible. Apparently the specs were totally wrong."
incompatible and specs wrong as he couldn't fit the 240V 3 pin plug into the 12V Socket?

Indeed, hence my question above your post.

Ian

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[Burkey]

Indeed, hence my question above your post.

Ian

Ok you’ve got me! It’s a question for my technical associate.

 

[autorouter]

I agree with the OP more than some on here, that a microwave is a good idea. All the advantages of a microwave at home in the kitchen (easy to reheat precooked meals, less washing up, less excess heat, etc) apply ten times more when camping and working in a restricted space.

If the problem is possibly tripping the site hookup post, then there is a solution. It's a bit of extra cost, but it works perfectly and is solidly reliable. A Victron Multiplus inverter/charger, maybe the 1600 version, will be fine for powering the average domestic microwave. The advantage of this setup is that is can work in combination with the hookup mains. If the hookup post has a 6A trip, you can set the input limit to 5A, and it will never exceed this 5A limit, so no chance of tripping the hookup post. But you will be able to use 5A from the hookup post plus the maximum inverter wattage (1200W = about 5A), so about 10A in total. So if you are running the microwave (5A or 6A), and the fridge switches on (about 240W = 1A) then there's no danger of tripping the hookup post. The extra power comes from the batteries via the inverter, and when the load drops, the charger automatically puts the charge back into the batteries.

I have a somewhat larger setup, with 600Ah of lithium batteries and a Multiplus 3000 inverter/charger. I set the hookup limit to 5A. For the last couple of weeks I have been on aires, with hookup posts with C6 trips (= 6A). I can run the fridge, microwave, rice cooker and travel kettle at the same time (15A total) and never be in danger of tripping the hookup post.

However if the OP is rarely going to use aires with hookup then just an inverter is the best option.

 

[Tombola]

I was not asking you though But as you replied, what makes that more suitable than dozens of others?

Gutted.

Nothing , as long as the others are 700w, white, and same size with a turntable, and dials.

 

[Hoovie]

I agree with the OP more than some on here, that a microwave is a good idea. All the advantages of a microwave at home in the kitchen (easy to reheat precooked meals, less washing up, less excess heat, etc) apply ten times more when camping and working in a restricted space.

If the problem is possibly tripping the site hookup post, then there is a solution. It's a bit of extra cost, but it works perfectly and is solidly reliable. A Victron Multiplus inverter/charger, maybe the 1600 version, will be fine for powering the average domestic microwave. The advantage of this setup is that is can work in combination with the hookup mains. If the hookup post has a 6A trip, you can set the input limit to 5A, and it will never exceed this 5A limit, so no chance of tripping the hookup post. But you will be able to use 5A from the hookup post plus the maximum inverter wattage (1200W = about 5A), so about 10A in total. So if you are running the microwave (5A or 6A), and the fridge switches on (about 240W = 1A) then there's no danger of tripping the hookup post. The extra power comes from the batteries via the inverter, and when the load drops, the charger automatically puts the charge back into the batteries.

I have a somewhat larger setup, with 600Ah of lithium batteries and a Multiplus 3000 inverter/charger. I set the hookup limit to 5A. For the last couple of weeks I have been on aires, with hookup posts with C6 trips (= 6A). I can run the fridge, microwave, rice cooker and travel kettle at the same time (15A total) and never be in danger of tripping the hookup post.

However if the OP is rarely going to use aires with hookup then just an inverter is the best option.

I can't disagree with a single point made above

My last campervan build I had a Multiplus 12/3000 (powered by 645Ah of Lead Carbon batteries) as I wanted to drive 2kW loads (Induction Hob & Water Heater), but whem I bought my current Motorhome, I evaluated precisely what size I needed for the new van and selected a Multiplus 12/1600, chosen specifically to support an 800W Microwave (this time I also happen to have a smaller 500Ah Hybrid battery).

 

[peterc10]

Ok you’ve got me! It’s a question for my technical associate.

A microwave needs 240v AC like you have at home. It won't work on the 12v battery system you have in the motorhome. That means if you want to be off grid with a microwave you will need an inverter to turn 12v DC to 240vAC. It will to be a powerful one so you will also have at least a couple of leisure batteries. And in order to keep them topped up when off grid, which means a solar system for sunny days and probably a B2B charger for high charging while you drive. All of that will cost

Your appliance engineer will not be able to help. You will need someone with expertise in motorhome electrical systems. There are plenty of Funsters on this forum that will help to guide you if you are reasonably handy with DIY. If you are not then you will have to pay more to get professional help to fit it all. In that case try Vanbitz eddievanbitz .

Your only other option is to use campsites with EHU and then you can plug your microwave into the 240v system in your motorhome.

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[peterc10]

I was under the impession that all c and cc sites allow all members the facility when passing to empty, fill up and use shower / toilet facilities on a”passing only” basis.
Using the sites visitor car park to park and use showers etc, but driving onto the drop-off points for filling.
No overnighting or cooking though.

Not all the C&CC sites allow this, just some. You are allowed in for 3 hours to use the facilities. They charge for it. Used to be about £7, but I suspect it will be higher now

 

[Captain Yoghurtpot]

Not all the C&CC sites allow this, just some. You are allowed in for 3 hours to use the facilities. They charge for it. Used to be about £7, but I suspect it will be higher now

Thanks for that clarity

 

[autorouter]

What was the issue with the early two? Is there a certain specification you need?

If you go into a random appliance shop, and are not sure what you want, it's possible you could come out with a combination microwave, with grill and oven incorporated. That would be too much for most inverters even up to 2000W. You'd struggle with one of those even with a 16A hookup.

 

[kingspeed]

I run a 700w on 16amph Hook Up.
If going without elastictrickery , then its gas and a large stir-fry pan.
Dont have lithium, solar or inverters as cant afford it and more importantly, dont fully understand it……………yet.!

I'm with the Cap'n

 

[kingspeed]

I run a 700w on 16amph Hook Up.
If going without elastictrickery , then its gas and a large stir-fry pan.
Dont have lithium, solar or inverters as cant afford it and more importantly, dont fully understand it……………yet.!

I'm with you Cap'n

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[Reallyretired]

I find a microwave occasionally useful as swmbo is allergic to fish. A lot of fish will poach fine in the microwave, which being in the garage (theres a space just the right size in there) is well out of her way. 700w working on 1.5Kw inverter or ehu if available.

 

[Burkey]

I agree with the OP more than some on here, that a microwave is a good idea. All the advantages of a microwave at home in the kitchen (easy to reheat precooked meals, less washing up, less excess heat, etc) apply ten times more when camping and working in a restricted space.

If the problem is possibly tripping the site hookup post, then there is a solution. It's a bit of extra cost, but it works perfectly and is solidly reliable. A Victron Multiplus inverter/charger, maybe the 1600 version, will be fine for powering the average domestic microwave. The advantage of this setup is that is can work in combination with the hookup mains. If the hookup post has a 6A trip, you can set the input limit to 5A, and it will never exceed this 5A limit, so no chance of tripping the hookup post. But you will be able to use 5A from the hookup post plus the maximum inverter wattage (1200W = about 5A), so about 10A in total. So if you are running the microwave (5A or 6A), and the fridge switches on (about 240W = 1A) then there's no danger of tripping the hookup post. The extra power comes from the batteries via the inverter, and when the load drops, the charger automatically puts the charge back into the batteries.

I have a somewhat larger setup, with 600Ah of lithium batteries and a Multiplus 3000 inverter/charger. I set the hookup limit to 5A. For the last couple of weeks I have been on aires, with hookup posts with C6 trips (= 6A). I can run the fridge, microwave, rice cooker and travel kettle at the same time (15A total) and never be in danger of tripping the hookup post.

However if the OP is rarely going to use aires with hookup then just an inverter is the best option.

Thank you for the time taken spelling out the intricacies of this option. I will ensure I have the correct set up before my next venture

 

[Burkey]

You haven’t indicated it thus far but do you actually have an inverter?

Ian

Yes I have an inverter and two leisure batteries

 

[Bolti]

Yes I have an inverter and two leisure batteries

But what size inverter.

 

[peterc10]

Yes I have an inverter and two leisure batteries

What size (in watts) is it and is it pure sine wave or modified sine wave?

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[EML]

Tombola……Absolutely brilliant, thank you. That’s exactly what I’m looking for , have a good weekend
Regards

The Tower specs give the "cooking" power as 650-700W, with a power drawn of 1100-1150W.

Modern ovens appear to be largely resistive loads (on the basis of minimal research and this one graph), so you probably wouldn't need a fancy (pure sine wave) inverter to power one. OTOH, the Tower looks anything but modern. If it has a transformer in it, you might have trouble with a 1500W inverter.

The link gives the results of a test of a 1000W Daewoo oven, which actually draws 1400W. The red and blue lines are very close when at full power (so it has a power factor of 1, ie. it's a linear/resistive load). So, basically, a cheap inverter should be Ok. YMMV.

 

[MisterB]

autorouter

damn you for putting more ways of spending money in my head .... Victron multiplus 3000 is now on my christmas list (for 2023 !!)

 

[Clive Mott]

We have a Daewoo 600 watt microwave in our little Hymer. It fits behind the top locker doors. Its powered by a large pure sine wave inverter and pulls just over 100 amps when working.

 

[Tombola]

We have a Daewoo 600 watt microwave in our little Hymer. It fits behind the top locker doors. Its powered by a large pure sine wave inverter and pulls just over 100 amps when working.

The one I listed above pulls 110. I find it more than adequate for in a mh.. we have a large inverter microwave at home supposedly singing and dancing and this isn't far behind in cooking / re heating time..we use it just for convenience. And is great for reheating the frozen or chilled meal favourites we make at home take with us on trips.

 

[peterc10]

The one I listed above pulls 110. I find it more than adequate for in a mh.. we have a large inverter microwave at home supposedly singing and dancing and this isn't far behind in cooking / re heating time..we use it just for convenience. And is great for reheating the frozen or chilled meal favourites we make at home take with us on trips.

Can it run with a modified sine wave inverter please?

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[Tombola]

Can it run with a modified sine wave inverter please?

Sorry I'm not sure, wouldn't like to say. I'm on renogy pure sine.

 

[Simonjdcooper]

Apologies I’m aware I’ve posted similar in the past but getting desperate for advice
I’ve recently sourced two 700w microwaves but discovered they are inappropriate and do not deliver to their specifications. The one recommended in earlier posts are not now available so would really appreciate any advice please
Regards to all

If you get an inverter microwave you can run that at a lower output and it provides that actual output, i.e 50% power set on a 1000w inverter will be supplying a constant 500w of cooking power. Whereas non inverter mictowaves simply cook at full power for less time when running at a lower output. I suspect the former would be more useful and less likely to get wrecked by a non optimal power supply and will draw a steady supply which may also be less likely to wreck your batteries. Hope that helps.

 

[Clive Mott]

Can it run with a modified sine wave inverter please?

Not advised

 

[Clive Mott]

If you get an inverter microwave you can run that at a lower output and it provides that actual output, i.e 50% power set on a 1000w inverter will be supplying a constant 500w of cooking power. Whereas non inverter mictowaves simply cook at full power for less time when running at a lower output. I suspect the former would be more useful and less likely to get wrecked by a non optimal power supply and will draw a steady supply which may also be less likely to wreck your batteries. Hope that helps.

Running a high power microwave in most cases runs the microwave at full power for a short time, then pauses for a short time, then repeats so that the average cooking effect is proportional to the % on time. But when on its full power it takes full lower. So any inverter has to be good for that. Our settup is Daewoo 600 watt microwave. (Assume 50%efficiency so 1200 watts in) A 1800 watt pure sine wave inverter and a 150 AH LiFeP04 battery. result is around 110A from the battery.

 

[Minxy]

A common misunderstanding about Microwaves is that the Power quoted is the Power drawn. It is not.

A "700W Microwave" is 700 Watts of COOKING Power. To know how much INPUT Power a 700W Microwave will draw, the label on the back needs to be referred to. It is probably around 1100W.
Plenty of people get a 1000W Inverter in order to use a "700W" Microwave. Too small.

Agreed, even Martin Lewis got it wrong on his show on Tuesday! He gave an example of power saving using a 650w microwave oven compared to a double power usage oven, mentioning the 650w power draw which it isn't - I assume he wasn't aware that the microwave would use MORE than 650w.

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[Garry - June]

Well we are replacing a death trap oven which is ridiculously situated well above our head . We actually need a footstool to view the contents and removing them involves a precarious balancing act . I I’m 5.10 but reckon the design engineer was 7ft tall ! Hence the decision to switch to a more safer method

100% agree with that...tec towers are horrendous things and as you say frankly dangerous... i will never buy a MH with that set up.. give me a fullsize cooker any day.