Hello everyone, didn't know where this should go so i stuck it here :P

I'm trying to get my carputer up an running but am having troubles with wiring.
I have a lilliput screen, and an old pc whose powersupply is 120w, which I want to hook up to a 160w inverter.

My main fear is damaging my screen. How would I go about wiring this without buying anything extra. In the near future I plan to get the m2-atx, but I want a temporary solution until I do.

Here are my thoughts:
1. Buy one of those cig light splitters, and hook up the screen to one, and the inverter to the other, which the pc would go into.

2. Tap into either (12v head unit wire or cig light wires) and connect them to the screen. Then use the cig light for the inverter and pc. Will this be too much power for the cig light?

Any ideas?