Is it possible to run a 800w microwave of an inverter? If so what size inverter to get and how long would a lb last before it went flat (100a lb) cheers

Hi,
yes you can run a microwave, though some inverters don't like it. At a rough guess you would need a 2000w inverter and I would say on paper your battery would last about an hour, in reality it is probably half that as you don't want to flatten a leisure battery as it will damage it.

There are some 12v microwaves on eBay, they use about 500w, so your battery would last 1-2 hours max.

Proper leisure batteries are designed to be used till flat.

CCSICeman wrote:Proper leisure batteries are designed to be used till flat.

I was told that it would damage the battery and there would be a problem charging it from flat.

dombutler wrote:

CCSICeman wrote:Proper leisure batteries are designed to be used till flat.

I was told that it would damage the battery and there would be a problem charging it from flat.

One of the many areas where there is much discussion and mis-perception. I don't claim to fully understand all of it but as far as I know:

A leisure battery isn't necessarily a deep cycle battery. And a deep cycle battery isn't necessarily a 'true deep cycle' battery. And even a true deep cycle battery will only withstand 80% discharging. And even then it'll still last longer if you keep it above around 50% charge.

A good rule of thumb seems to be that if your battery cost you less than £800 then you can't discharge it without killing it. And if it came from Halfords and has a picture of a caravan on the front then you've just paid three times the price to get a big car battery. I'm oversimplifying of course

If you want to read more:
http://en.wikipedia.org/wiki/Deep_cycle_battery
http://jgdarden.com/batteryfaq/carfaq.htm