I have a 1000w inverter and a 1200w microwave, naturally the microwave doesn't work so do I buy a bigger capacity inverter or a smaller wattage microwave ? If I get a more powerfull inverter would it be just a straight swop for the old one or would the wiring need uprating. Also what size inverter should I get?
Inverter question
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Lenny HB
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A smaller microwave would still need a bigger inverter, microwaves take about twice the power of there cooking rating.
To power your 1200 watt microwave you might get away with a 2000 watt inverter but 2500 would be safer.
Bear in Mi d if you have standard batteries for a 2000 watt inverter you wil need 800 ah of batteries.
To power your 1200 watt microwave you might get away with a 2000 watt inverter but 2500 would be safer.
Bear in Mi d if you have standard batteries for a 2000 watt inverter you wil need 800 ah of batteries.
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Microwaves are often described by their microwave output rather than the electrical input which can be a lot higher. Is the 1200W the output or input? Usually the wiring to the inverter input is the minimum required for that inverter model, and a larger model will almost certainly require the wire to be upgraded. However it's possible to add extra wire - doubling up the existing wire for example - because what matters is the total cross-sectional area of the cable. And a bigger fuse may be required too.
But probably the biggest problem will be whether there is the battery capacity to run the more powerful inverter. There is a limit to how many amps can be taken from each battery.
But probably the biggest problem will be whether there is the battery capacity to run the more powerful inverter. There is a limit to how many amps can be taken from each battery.
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- Jul 5, 2013
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Try www.microwave-repair.co.uk
They specialise in microwaves for motorhomes, caravans and trucks. They are based in Sellindge in Kent, but deliver all over the UK. They specialise in throttling back the power used by microwaves for those with smaller inverters. They produce models that have output powers as low as 500W. This will mean that you will use the same amount of power to cook something, but it will take longer to do so. They say that the microwaves they sell can usually be used with modified sine wave inverters as well as pure sine wave.
I have just bought a microwave from them for use with my 2000W/4000W inverter. It was one that didn't need throttling back. The stated output power is 750W - 800W and the input power is stated as 1200W - 1270W. I have tried it with the inverter and it works! And it only cost me £80.
But, as others have said you will need to upgrade your battery bank because high draw rates will ruin lead acid batteries. On full power the microwave I have bought is drawing 100 amps. So the choice is to buy a lot more lead acid batteries (if you have the payload) or change over to LiFePo4 batteries, like I did. I have two 120Ah batteries and each can safely draw 100A, which means that each is drawing only half that when the microwave is running.
And finally remember you will need to be able to replace the power you use. So you will probably need more solar and a B2B. So the cost of the microwave is the least of your problems.
Edit. Sorry, the best way to contact them is on this link.
They specialise in microwaves for motorhomes, caravans and trucks. They are based in Sellindge in Kent, but deliver all over the UK. They specialise in throttling back the power used by microwaves for those with smaller inverters. They produce models that have output powers as low as 500W. This will mean that you will use the same amount of power to cook something, but it will take longer to do so. They say that the microwaves they sell can usually be used with modified sine wave inverters as well as pure sine wave.
I have just bought a microwave from them for use with my 2000W/4000W inverter. It was one that didn't need throttling back. The stated output power is 750W - 800W and the input power is stated as 1200W - 1270W. I have tried it with the inverter and it works! And it only cost me £80.
But, as others have said you will need to upgrade your battery bank because high draw rates will ruin lead acid batteries. On full power the microwave I have bought is drawing 100 amps. So the choice is to buy a lot more lead acid batteries (if you have the payload) or change over to LiFePo4 batteries, like I did. I have two 120Ah batteries and each can safely draw 100A, which means that each is drawing only half that when the microwave is running.
And finally remember you will need to be able to replace the power you use. So you will probably need more solar and a B2B. So the cost of the microwave is the least of your problems.
Edit. Sorry, the best way to contact them is on this link.
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So if I buy a 2000-4000 inverter and a microwave like yours would my two X 130ah lead batteries cope ? I have 2 x 100 watt solars
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- Jul 5, 2013
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They would cope, but not for long I think. When running the microwave on it's full power it draws just over 100A, i.e. 50A per battery. I think that large a draw would shorten the lead acid batteries' lives considerably. We have 2 x 120Ah LiFePo4 batteries and each battery can draw 100A safely. As for solar that will depend upon how long you use the microwave each day and what weather you have. If you run the microwave for say 20 minutes per day it will take out 35Ahr. With 200W you would struggle to put that much in in a day if it is cloudy.
I have just finished installing the microwave and electrics and we are very pleased with it. The only problem is that it is installed high up so we have just bought a folding stool so that SWMBO can reach it and look into it. We already have 250W of solar and, now that I have finished installing the microwave, my next job is to install another 2 x 100W panels once the weather gets drier.
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MisterB
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We had our microwave adapted by them, it works perfectly well through a 2000w PSW inverter and 300ah lithium.
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Tombola
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this is a good un Ive use for a few years. 700w, ran on my previous 200w inverter ok.
And yes you probably will need to uprate your inverter cables, how many mm do you have now, 2000 wants 25mm
Amazon product ASIN B0856LRSWJ
And yes you probably will need to uprate your inverter cables, how many mm do you have now, 2000 wants 25mm
Amazon product ASIN B0856LRSWJ
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I've got 200 amps of lead acid leisure batteries, 200 watts of solar and a 60amp B2B.
I don't have a microwave as to run it would mean getting lithium (or probably another 3 more 100AH lead acid batteries which I don't have room for) and I'm not prepared to pay for lithium just to use a microwave once in a blue moon
I don't have a microwave as to run it would mean getting lithium (or probably another 3 more 100AH lead acid batteries which I don't have room for) and I'm not prepared to pay for lithium just to use a microwave once in a blue moon
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SHMBO uses the microwave at home to heat a bowl of porridge 1min,1 cup of milky cofee 2 mins, reheat a pizza 3 mins, not all at same time and on different days. I other words we are never going to run a microwave for anything like 20 mins, So am I still under powered as in post #7+ 8 ?
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Simplist (and probably cheaper) is smaller microwave, just means it will take slightly longer for your porridge.
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The problem isn't the length of time these high drain electrical items will be used for, it's the amount of amps they will draw out of the inverter for the short time they will be running.
Standard lead acid batteries are only rated at continuous discharge of about 20% of their amperage.
So although the microwave may only be running for a few minutes, for those few minutes it will be drawing say twice what your batteries are rated to deliver.
If you only did this once in a blue moon, say in an emergency, you probably wouldn't notice much if any degradation of your batteries.
However do this a few times a week regularly and you will soon be buying new batteries.
This is why people who use high drain items like microwaves, hair dryers, electric kettles etc have lithium as lithium are rated to deliver 80-100% of capacity in draw ie a 100amp lithium will happily deliver the 100AH the microwave needs without damaging it where as a 100amp lead acid battery will only deliver around 20AH before it is unhappy.
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- Jul 5, 2013
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I am not sure about some of your timings. I use the 1000W (output) microwave at home to cook porridge and it takes 6 minutes! And, as headlight says, it is not the total amount taken, but the rate that it is being taken out at will cause problems to your batteries.
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Lazysquirrell
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I had a 3000w sine wave interter with an 800w microwave. Worked fine but hardly used it, my daughter now has microwave but kept the inverter as handy for vacuuming etc.
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Thanks for the input (and output) everyone it's clear to me now that I should only use the microwave when on EHU . I can't justify replacing my batteries, inverter and microwave just to have a milky coffee now and then. I realy do appreciate the advice thanks again.
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MisterB
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I don't disagree re the cost, but if you ever do get round to having to replace battery etc, it's well worth considering. Just being able to flick a switch for the electric kettle in the morning rather than waiting for the kettle to whistle on the gas stove, being able to make a hot drink and even cook something while waiting in the queue with your gas turned off are just a couple of benefits in addition to milky microwave coffee !! We always used to make a flask up when travelling so we could have a hot drink without having to use the gas, nowadays we use the flask just to store excess hot water from the kettle, ready for the next brew!
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I use one of these for milk: Amazon product ASIN B09JC3ZK1DWorks a treat and only 550W so my 1000W inverter and 100Ah lead acid has no issue.Yes porridge, warm milk for a latte, packet rice, vegetables etc etc even bacon in one of those microwave bacon cooking things.
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Except that a 100AH lead acid battery is rated to discharge at 20 amps/hour where as your inverter powering a 550 watt 240v device will be drawing maybe 3 times that amount so you will noticeably reduce the life of your battery if you are doing this regularly.
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Well should be fine, it takes a few minutes so I certainly won't be using 50% of the battery. Even if the inverter draws 50A for that time I doubt it will be an issue as long as the battery is well charged of course. I should add my last battery lasted between 4 and 5 years which I consider not bad given that it stays out in the van all winter, topped up by the solar and EHU in the dead of winter. If I bought a new van now then I would go full lithium, but not worth changing now. The main use case for my inverter is charging 3 electric bike batteries. Bacon goes on the BBQ
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