What 12v Inverter

• Firstly Karl, you need to decide what you are going to run through it. I would certainly (and do) heat my kettle on gas (Safefill). We use Toaster, Microwave, blender and vacuum. If there is anything that requires a pure sine wave then your decision is made for you. However, most electrical appliances work perfectly well off modified sine wave. I bought a PSW model simply because I wanted to be sure that anything I ran off it would be OK. Once you have decided the sine wave the next question is how powerful. I bought a 2k because I knew that the highest power draw would be about 800w due to start up of microwave etc. I didn't want the thing working at its max so I bought a higher powered one so that I had plenty of 'slack' in the system. Just one point. The battery/s at the back of an inverter needs to be in tip top condition. I have two 110ah which will be changed this year due to the fact that they are getting ' tired'. However, they are 4 yrs old and have worked well but they are not now holding the amount of power I need for say the toaster or the microwave. I was talking to a guy on site only this morning and he changes his batteries every 3 years(whether they need it or not!) I would love Li Ion but the tech is still a bit dodgy although I read reports in the last 24 hrs that they have cracked the safety issue with them but they won't be commercial available for some years yet. Hope this helps 

"Pure Sine Wave" is a bit of marketing speak for "Square wave with more steps".  It is still far from the perfact sine wave produced by a rotating mechanical generator.

However it is good enough for most electrical and electronic devices that have a transformer or a motor as the main load as it self-smooths the bumpy square wave. In the process there will be the usual problems - hum, heat and harmonics. But if it's just on while the steak pie gets heated one can probably live with it and its high rate of power consumption.

What will work badly if at all are devices that rely on the input being a true sine wave - usually reading the peak voltage for accurate timing.

. But if it's just on while the steak pie gets heated one can probably live with it,

yep I guess that says it all Nav. All my 240 v kit is on for only a short time but does a excellent job - or did so before my batteries started on their downhill run. Banner Bulls next time. 

Battery is good only just brought a new Platinum 100amp class A when we got the van this year so only a couple of months old.

So if a modified sine wave will do then that opens up a lot more opportunities although still got to try to make sure I don't end up with some Chinese tat.

Was looking at 1500w or 2000w to be honest, better to have too much than not enough, it was really just the sine wave bit that I did not know about, but if a microwave and hoover will work on a modified then that will do me.

That's it Karl, build 'slack'  into the system. A 1500 or 2000 should do nicely.   As long as you don't intend to run sensitive equipment that require PSW you should be fine.  If you can make it I would wait till the show. Loads of good advice there. 

Cant go to the show will be away on holiday so missing the caravan show and the scuba show but holiday will make up for it.

That's a pity, everything you need under one roof! I always find the shows really useful- there is always some new tech going on or new gadget that makes life easier. Problem is, it's so big ,I need some new running spikes!!