Im planning to run a PC (as a car computer) and a 100watt amp with a touchscreen as well. Thinking about a dual battery setup what d'ya reckon?? problary wont use the stereo too much with the car turned off. Another question, DC-DC powerbox for my computer or just a power inverter... arghh so many decisions???

Up too you really whther to just get one high quality battery such as a yellow top optima and make sure u dont run stereo/incar pc for long periods when the car is off...that will be fine...

If you go 2 still a good option (even better when run through a relay) you will have to work out where it goes eg: boot. which involves running cables....upright vented box (if the battery isnt a gel or dry cell)...extra fuse and fuse block if u go that far etc etc.....

Need to find out what size Power supply is in your PC and better the current draw of all the device u want hooked up...too then calculate how many amp hours u will be drawing from your battery when the car is off/on......

For the PC just buy a good 300 w inverter ones with dual power outlets can u set u back around $350+ for a good one