Wooie Posted January 17, 2013 Share Posted January 17, 2013 I have a Microwave that was fitted in my van from new ( Explorer Group ). The Model Number is...................................WP550L12. The Specifications i have are:- Power Consumption.................................... 230V ~ 50Hz, 900W. Rated Microwave Power Output.................... 550W. Operation Frequency .................................. 2450MHz. Realistically what size Inverter would i need to run it ? Regards. Link to comment Share on other sites More sharing options...
lennyhb Posted January 17, 2013 Share Posted January 17, 2013 I would go for at least a 800W with a 1200W surge capability. as microwave start up current can be up to double to running current. Allowing for approx 90% efficiency of the inverter you will be drawing about 50 amps at 12V so you would also need a big battery bank, 2 x 110 ah as a minimum if you intend to spend more than the odd night or two off hook up. Link to comment Share on other sites More sharing options...
Tracker Posted January 17, 2013 Share Posted January 17, 2013 We have a similarly rated microwave and after some research opted for a pure sine wave 1500 watt inverter and it works well with no problems which, for us at least, fully justified it's cost. http://midsummerenergy.co.uk/buy/sine_wave_inverters/Fountainhead1500WPS.html I located it in a well ventilated spot on the end of the bed locker and I switch it off when not in use as the 10 watt consumption would flatten the batteries. Link to comment Share on other sites More sharing options...
Guest peter Posted January 17, 2013 Share Posted January 17, 2013 You don't need to go to the expense of a pure sinewave inverter but I'd have thought it would need to be at least 1500 watts, because of the startup current. Link to comment Share on other sites More sharing options...
Guest 1footinthegrave Posted January 18, 2013 Share Posted January 18, 2013 Drawing the kind of current you'll have flat batteries in no time,and you'll need some seriously heavy duty cabling to connect to the battery/s to the inverter, then your faced with the problem of re-charging them, work out the current used and be surprised how far you'll need to drive to re-charge them, add in the fact that batteries are only capable of a certain amount of charge discharge cycles you'll shorten their life considerably, so all in all although we have a 1200 watt inverter it rarely if ever gets used because of these factors apart from the odd charging of my laptop,for which it is overkill but was in the van, we just opt for food that can be cooked using gas, seems a no brainer for me, and a microwave ( if we had one ) would be a mains hookup jobby only. Link to comment Share on other sites More sharing options...
sambukashot Posted January 18, 2013 Share Posted January 18, 2013 Agree with 1footinthegrave, to add you will need a pure sine wave invertor to run a microwave correctly!Best to run the invertor off the vechicle battery with the engine running rather than run down your leisure battery... Link to comment Share on other sites More sharing options...
Frankkia Posted January 18, 2013 Share Posted January 18, 2013 A big inverter can be a good idea if you regularly spend time on sites where the connection is 5amp or as we came across in Germany an extortionately priced 2amp hook up. Then you can still run larger electrical items or 2 or more smaller ones at the same time without tripping the fuse. That way the meagre supply will continue to put back a charge to your batteries after you disconnect the appliances. I once hooked up the water heater on one 'van to an inverter whilst on a 5 amp site. Saved a bit of gas - who said Yorkshire men are tight! But quite right - heavily depleting your batteries on a regular basis will shorten their operating lives. Link to comment Share on other sites More sharing options...
Tracker Posted January 18, 2013 Share Posted January 18, 2013 I too understand that a microwave works better with a pure sine wave inverter and for the sake of a few quid is it worth the possible aggro of it not working so well, or failing earlier, on a modified sine wave unit? Bear in mind that a microwave typically runs for only a few minutes at a time - say 10 minutes? 900 watts at 12 volts is 75 amps so if it ran for an hour it would consume 75 a/h - probably nearer 90 given the system - so for 10 minutes you can say goodbye to about 15 a/h of your leisure battery so as long as you have 200 a/h of well charged battery and don't make a habit of it without a couple of hours driving in between there should be no issues - and there have not been for us. I have my batteries wired as per the second diagram down on the link as I am given to understand that it gives a more even power drain and charge shared between the two. http://www.solarrvpanels.com/index.php/tag/wiring-12-volt-batteries-in-parallel/ Link to comment Share on other sites More sharing options...
Guest 1footinthegrave Posted January 18, 2013 Share Posted January 18, 2013 Just to be the devils advocate a microwave can be had for £40, a pure sine wave inverter the last time I looked were considerably dearer than modified one, so if the £40 micro did go poof it would not be the end of the world, but to be honest I cannot understand anyone wanting to go to the trouble and expense just to microwave a ready meal when not on a mains hookup, when a few minutes on a gas hob will do the job, unless you want baked tatters, but horses for courses I guess. Must confess never thought of Frankia's dodge though, useful tip, thanks Just pulled this up on the net, maybe useful information for the OP, even though it refers to US mains voltages, the principal would be the same. Notice that to produce 62 Btu of heating in 3 minutes requires that the inverter input be greater than 14 Volts! That is, to get the same amount of heating power as 120 VAC sinewave, the inverter must be run when charging, since batteries alone will not provide 14 Volts. Notice how inefficient the microwave is when the inverter is driven by 11.5-12 Volts, a rather typical range with heavy draw. Without knowing why the microwave oven performs better on a higher DC input, immediate and useful conclusions follows. If you have an inverter, use it when the batteries are fully charged. It also helps to have batteries that hold up their voltage under heavy loads. We touched on this subject in Living on 12 Volts with Ample Power without getting into the whys and wherefores. Liquid electrolyte deep cycle batteries with thick plates sag quite severely with heavy loads. In the case of our experiment, the inverter drew about 100 Amps. A fully charged liquid 8D battery fell almost immediately below 11.5 Volts. In the graph, the measurements below 11.59 Volts were taken with a liquid 8D Link to comment Share on other sites More sharing options...
Clive Posted January 18, 2013 Share Posted January 18, 2013 1500 watt inverter for l peace of mind. And If you want to be sure that anything else will work including that microwave from a non pure sine wave inverter then TRY IT FIRST. I have blown up inverters just by connecting one brand of Laptop power supply to it. Other brands OK. So Pure sine wave covers all and gives peace of mind. Deeper pocket required though! C. Link to comment Share on other sites More sharing options...
weldted Posted January 18, 2013 Share Posted January 18, 2013 Hi I have a 2000 watt pear 1000 constant inverter running from my engine battery, cables 25 mm squared this inverter has been used since 2005 to run either an 800 watt vac or a 700 watt microwave. It is now in its third van. I use the engine battery as starter batteries are more suited to high current loads both on discharge or charging, where a leisure battery is more suited to longer lighter loads both in and out around 10 - 15% of its capacity. Running either unit for ten mins still leaves plenty of amps for starting, if I need longer I just run the engine. I have also a 50 amp battery to battery charger and 300 watts of solar, I run the solar lead to the engine battery to ensure that it is always topped up first then any surplus going to the leisure batteries (2 x 100 amp) via the b2b unit. Covered some 90,000 miles since 205 no problem. Link to comment Share on other sites More sharing options...
Losos Posted January 21, 2013 Share Posted January 21, 2013 A 1500 watt inverter would be the smallest you could use and I would recommend a pure sine wave type, as mentioned you'll not have to worry about damaging any kit with a pure sine wave type, from an engineering point of view the other types are at best a compromise and at worst down right dodgy. Link to comment Share on other sites More sharing options...
Guest peter Posted January 21, 2013 Share Posted January 21, 2013 Why mess about with an inverter anyway. Just get a 2 Kw digital (dirt cheap as long as it's not honda) generator and as it will only be running for a few minutes it won't be too much of a nuisance. Plus you can use it for other purposes. Link to comment Share on other sites More sharing options...
Tracker Posted January 21, 2013 Share Posted January 21, 2013 peter - 2013-01-21 7:43 PM Why mess about with an inverter anyway. Just get a 2 Kw digital (dirt cheap as long as it's not honda) generator and as it will only be running for a few minutes it won't be too much of a nuisance. Plus you can use it for other purposes. As long as you have space to store it and don't mind faffing about with petrol - which also needs to be carried and stored - along with sundry bits and bobs for when it needs attention!! Link to comment Share on other sites More sharing options...
Guest 1footinthegrave Posted January 21, 2013 Share Posted January 21, 2013 Tracker - 2013-01-21 7:46 PM peter - 2013-01-21 7:43 PM Why mess about with an inverter anyway. Just get a 2 Kw digital (dirt cheap as long as it's not honda) generator and as it will only be running for a few minutes it won't be too much of a nuisance. Plus you can use it for other purposes. As long as you have space to store it and don't mind faffing about with petrol - which also needs to be carried and stored - along with sundry bits and bobs for when it needs attention!! Or just settle for a cheese sandwich, even less of a faff. ;-) Link to comment Share on other sites More sharing options...
lennyhb Posted January 21, 2013 Share Posted January 21, 2013 My view is if it don't work of 12 V with a reasonable current draw it's not fit to be in a Motorhome. :D Link to comment Share on other sites More sharing options...
Guest 1footinthegrave Posted January 21, 2013 Share Posted January 21, 2013 lennyhb - 2013-01-21 10:46 PM My view is if it don't work of 12 V with a reasonable current draw it's not fit to be in a Motorhome. :D I second that, Microwaves, hair dryers, vacuum cleaners, I'd sooner stay at home. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.