Inverter question

Azurepink · Member

Inverter question

KFT · Guru

G'day Azurepink

It depends on the input your m/wave requires. I would think many need at least 1200 watts or near to that so your 800w inverter will drop the load.

you need to have a look at the specifications for you m/wave and see what the input power requirement is. This info may be on a label somewhere or in the instruction book.

frank

Azurepink · Member

KFT wrote:
G'day Azurepink

It depends on the input your m/wave requires. I would think many need at least 1200 watts or near to that so your 800w inverter will drop the load.

you need to have a look at the specifications for you m/wave and see what the input power requirement is. This info may be on a label somewhere or in the instruction book.

frank

Frank thanks. The only info we have is "4.8 amps, 700w."

TIA

KFT · Guru

Ok then I reckon a m/wave that will draw 4.8 amps will want at least 1100 watts to run and a bit more to start.

I think you would require at least a 1500 watt inverter and a big battery bank. you would not want to run the m/wave for very long.

When we need to run the m/wave away from power I start the genny

frank

Peter_n_Margaret · Guru

Microwaves are a trap. Frank has is right.
The "700W" quoted for the microwave is the OUTPUT, not the input, which in some cases can be double.
You would also need a large capacity house battery bank to run a microwave for more than a minute at a time.

Cheers,
Peter

madaboutled · Guru

When it comes to inverters, solar and battery systems I tend to go with the recommendations from the solar experts who create these systems for houses which are 100% reliant on their solar system for sometimes many days at a time. Some of the best systems use a 5 to 1 ratio thats 5 days running for 1 day charging off solar only, this equals lots of panels and lots of batteries.

OK, so motorhomes & caravans are different you only have a small area for panels AND you are very limited on batteries due to weight. Most motorhomes & caravans can only work on a 1 to 1 ratio (and some can't even do that), and if theres no sun the next day out comes the gennie or charge off the vehicle.

For inverters, the solar experts recommend calculating the power draw of all your appliances including those that run on 12v like light etc... for daily use all your then whatever power draw they come to the inverter needs to be 3 times that. This will allow for appliances that need extra power for start up like microwaves.

These same rules should be applied motorhomes & caravan systems taking in to account we are very limited by both panels and battery capacity. Without going into figures, running a microwave off an inverter for as little as 5 minutes and assuming your batteries have the capacity, this will draw that much power from your batteries that the solar panels you have would be battling to replace in one day.

So, in the case of appliances such as microwaves I like many say leave them off till you have grid power or a gennie to run them off.

Then of course theres a 12 volt microwave, again though not ideal as this topic suggests http://thegreynomads.activeboard.com/t51715414/12v-microwave/

Hope this helps

Regards Steve.

gemmybob · Veteran Member

Interesting, one would have thought a 700 watt microwave would use 700 watts, but doing the calculations using volts and amps gives around 1200 watts. Therefor a micro wave with a 700 watt output takes 1200 watts to run. Could be a trap for young players I think.

-- Edited by gemmybob on Monday 16th of February 2015 10:53:37 AM

03_Troopy · Guru

Just an interesting addition to the previous posts, you can check the output of your microwave oven by doing as described here. Which is the same as how I used to check them when I repaired them. When it was still worth repairing them that is.
How to check MWO output power.

And yeah, the 12V MWO's draw over 60A for a 700W job.

Azurepink · Member

Thanks everyone for all comments. Much appreciated.

madaboutled · Guru

03_Troopy wrote:

How to check MWO output power.

Thanks for posting that, might use it to see what my microwave is cabable of cause nothing is labeled on the front of it and it's working so don't want to pull it out of the cabinet. It's a nice simple test and might help with my cooking by knowing the output cause I over nuked some lassanga the other night.

Regards Steve.

-- Edited by madaboutled on Monday 16th of February 2015 06:52:07 PM

Philw · Senior Member

Hey Guys. I dont know much about Inverters etc., but our Motorhome came with one when we bought it. The microwave plugs into a Inverter power point. We have two house batteries and a 80 watt solar panel. When free camping last year, I used the microwave 2 to 3 times a day for 4 mins each for a heat pack for my back. Plus the wife used it for the occasional cooking. We were running off batteries for 10 days. Water pump, music and lights. We never ran out of power and the panel fully recharged the batteries by the end of the day. Apart from airconditioning, cant see the need for a generator.
Cheers
Phil