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I know the topic of inverters has come in the past to power other items on the boat. What I am looking to do is gain access to my microwave for up to 2 minutes away from the dock. Our youngest child will be one year old for the up coming season and small mircowavable meals would help our days out on the boat. Can this be achieved? I am not looking to run a/c, heat, or anything else. I just want to use the microwave for short spurts. Any feed back would be appreciated....
I had a similar problem. My wife also would like the use of the microwave, popcorn etc. I will also like to have power if I do overnighters for lights also. Instead of a large battery to run an inverter I just bought the honda 2000i generator. Around 46 pounds 15 - 30 amp adapter plug into shore power cord and I'm all set. This can run more things than the inverter and it has inverter type current outflow.
Location: Quebec, Canada and Pirates Cove, OBX, NC
Posts: 17,813
Inverter to power small microwave.
I looked at the small generator and inverter option.
I am installing a 2,500 watt inverter this winter . . . much bigger than my microwave needs . . . I like the "don't have to start a generator" option to use the microwave . . .
The generator, however, does allow you to charge your main engine batteries is something happens out there . . . there might be a generator out there for me in a year or two
Hi guys - just a heads up!!! Before you put in an inverter to run a microwave, do some more research.
I thought I heard a couple of years ago that the sine wave of electricity that comes out of an invertor will not run a microwave, or maybe it damages a microwave, just don't remember.
Might have been all BS at the time, and maybe changes have been made since then, but at least check it out.
Maybe someone here runs a microwave off a invertor?????
At that time I was told I would be better off to invest in a generator.
Ok....I went and did some research. I took the following out of a website:
"SINE-WAVE or MODIFIED SINE-WAVE. The sine-wave inverters will provide exceptionally "clean" power for sensitive equipment, such as computer systems, copy equipment, microwaves, audio equipment, bread makers and some motors. For instance, microwaves can take 30% longer, fan motors will hum, stereos may have static, refrigerator motors will run hotter, laser printers will burn up, and some copiers fail to operate in a system using a modified sine-wave inverter."
So it appears you guys will have no trouble as long as you run a "Sine-Wave" inverter and not a "Modiified Sine-Wave"
Do the math, amps=watts divided by volts,
for 12 volts to make 120 volts at 1200 watts, multiply the amps reguired by 10, (normally 10 amps at 120 volts) now 100 amps at 12 volts....there is some loss across the inverter, a 15 amp output inverter will power your micro, a two minute use of the micro should use 17 amps....my head hurts...Mick
You've got it right Dockmaster, you need a true sine-wave inverter.
B, I suggest you choose the microwave first. Then check the current (amps) or input watts requirements. (Volts x Amps = Watts) Remember a 750 watt microwave will take quite a bit more input power.
Once you know the output power requirements of the inverter (> than the input power requirements of the microwave), you have to watch the specs ! Most inverter are rated by peak power, but you need one whose average power meets your requirements (ususally motors, like a power drill or saw, have high peak power requirements)
Now the bad news. True sine-wave inverters cost a whole lot more than modified sine-wave inverters !
Finally, if you are going to make the investment, make certain you have the right gauge wire for the distance you are going to run from the battery to the inverter. Remember to double the length (the electrcity has to go there and ******.
Xantrex is the biggest seller of inverters. They sell under several names including Heart, Freedom and ProSine and ProWatt. Xantrex Marine Catalog
You need some serious batteries and wiring to run an inverter big enough to run a microwave. The leads from the battery to the inverter will be #2 and no more than five feet (each wire) in length. The inverter is not ignition protected so finding a place to mount it can be difficult. I am starting this same project, the cost of materials including batteries will exceed the cost of the inverter.
I battled with this same problem, and decided to go with a small (600 watt) Xantrex inverter so we can watch DVD's at night while anchored out in a cove somewhere, and a small portable generator for when I need more power and to charge up the batteries.
While camping out for a week, at one point during each day I'll fire up the genereator, plug it into my shorepower inlet, and use that to charge up the batteries and run all of my AC stuff.
A 750 watt microwave refers to the output of the magnetron tube. It may nuke your food with 750 watts, but the light, the fan, and possibly a turntable all consume watts also. If your microwave takes 1000 watts to run, a 1000 watt inverter may not cut the mustard.
The cooking power of a microwave oven is the average output of the magnetron over time. The magnetron is cycled on and off to vary the power and to keep the magnetron from overheating. For example, a smaller, 1000W cooking power microwave oven, on the high setting, may draw 1500W and be off half as long as it is on (i.e. a 2/3 duty cycle). That gives the 1000W cooking power rating. On the medium setting, it would still draw 1500W, but may only be on half as long as it is off. You get the idea.
For the oven in this example, I'd want a ProSine 1800, and use adequate cable to the batteries for 225A.
Keep in mind that running this 1000W microwave is about like cranking a V8 engine that won't start.
i have been running a 650 watt microwave with a 1000 watt inverter hooked to an 8d batter via number 4 cables about 15 feet long. as per the previous comment, you need an inverter rated about half again as big as the advertised power of your micro.
as policy, i try to only run the micro when the engine is running and charging, although it works ok when the engine isn't running.
Greg,
Others have posted some good info. If you do purchase an inverter, I would test your micro w/inverter before you install everything permanently.
When you perform the test, make sure you test with the engines running (13.6 volts at the battery) and engines off.(12.5 to 12.8) at the battery. That 1 volt could square off the sine wave more.
Cable gauge and lengths are critical so try to use what your going to install permanently.
In the world of AC, volts times amps does not equal watts, it equals VOLT-AMPS. There is a multiplier called Power factor that is a function of the type of load that you are driving. If you are feeding incandescent lamps, the Power Factor is 1 (one) and volts times amps times one equals watts, ie, they are the same (1000 volt-amps = 1000 watts). When you are driving inductive loads like motors, transformers, magnetrons, etc, the Power Factor is always less than one, so 1000 volt-amps may only drive 500 watts with a power factor of 0.5. This rule applies whether you have a sine wave supply or square wave supply. The square wave makes it more ugly since those sharp wave fronts radiate high frequency voltage spikes that can punch through the wire insulation of motors, magnetrons, etc, and create lots of radiated noise into any electronic equipment.
I would suggest that you contact the Inverter manufacturer and tell them the type of load you want to drive with their Inverter and they should be able to tell you the maximum Microwave size that their equipment will drive. I would guess at least a 2 to 1 ratio, ie, 2000 VA Inverter for a 1000 Watt Microwave.
Inverter to power small microwave. 
