To add to Pete'e comment, be very careful about using those larger wattage devices. The conversion of 12v DC to 110v AC generates a substantial amount of energy (often heat) - potentially running through wires not designed to handle that load. It is easy enough to MELT the wiring in the dashboard (lighter socket, fuse box, etc.). Most car wiring can handle that extra power for a few seconds (like to heat the cig lighter), but not for a prolonged period of time. Check your vehicle owner's manual to find out what the 'sustained' load capacity is. When in doubt, like Pete recommended, get a heavy guage extension hooked directly to your battery by a pro. Only costs a few bucks and could save you a bunch in unexpected rewiring costs!! TJ