I have a 600 watt 12v invertor which I bought from Maplins before it shut and it has served me well but I need a new one now and was wondering what to go for !!! I cant see why some are hundreds of pounds and some not. The 600 w was fine and I was wondering if I could put a 800w one on, or if that's a waste because my alternator wont be able to handle and more power, I have a canal line 38 engine. I also reckon a modified sine wave would be fine from reading about it as I only want it for tv, laptop and charging phones tablets, etc. Any advise please