Have come up with a solution regarding the proverbial "How to run a hairdryer/microwave from 12volt" problem. We hardly ever use campsites as we don't need hookups, but there has been a problem recently that I never had before, and that is the damned hairdryer. All our appliances are 12volt and we have adequate solar/wind generator to recharge the leisure batteries. Having purchased a 3000 watt inverter at Hagers bring and buy I was wondering what to do with this monster. In a flash the solution to the hairdryer came to me. So I have a battery completely separate from the leisure batteries which the inverter is coupled too, with a remote on/off switch and the same gizmo I have keeping my engine battery topped up with any excess power from the solars. How it works is this...Once it detects that the leisure batters are up to 13.6volts the relay opens and feeds any power the solars produce into another battery bank. Thereby only charging the second bank after the first is full. Once the relay detects that the leisures have dropped below 12.5volts it switches off. My reasoning behind all this is that there is no chance of the main leisure batteries deep discharging and leaving me with no power. OK the big inverter will not run for long on full power but it will run the hairdryer long enough for herself and will cook a FB pie in the halogen oven...even though I wouldn't touch a FB pie with a big stick. These relays are available on evilbay at £18-99 each, so if your worried about flattening your main leisure batteries with an inverter, this is the way to go.