So I'm in the process of wiring up a power supply for my car computer project (more on that in a thread later ). I'm having a hard time finding the best places to splice to get a 12v connection and an ACC connection (so basically one that is on all the time/directly connected to the battery, and one that is switched on with the key in).

I've heard some recommend going directly to the battery terminal for a reliable 12v connection, but routing wires through the firewall is such a pain. I'm hoping to avoid that if I can.

For the ACC connection, my best guess so far is to tap into the cigarette lighter wire.

Has anyone gone down this path that might be able to suggest what would work best for each/either?

 

I have and you need to look at the sticky thread "Hot or Not (Fuses)" gives you al the info you will need about what circuits to tap into

best grounds are under the door sill covers.

 

How much power are you going to need plus a little extra? If doing an in depth install like a carputer I would highly suggest a dedicated power source from the battery with a fuse. The battery compartment has an area to punch the wire right through the firewall rather ease compared to other cars. IMO better to be safe and correct than sorry.

 

Carputers do not need the HIGH current that amps need so no real need to punch thru the fire wall with a dedicated line. THere are more than enough places in the fuse box to tap off of for the 10 amps or so needed.

 

I guess I was surprised to see it only needs 10amps. My previous experience with PC building was a much higher power demand unit (overclocking and performance parts). I would have thought the carputer either drew more DC amps or had a 120v inverter that would also require power and have a small amount of subsequent loss due to inefficiency.

Slightly related, I had a compressor (much higher draw) that melted some wires and eventually blew the fuse but even that was not instantaneous. The motor burnt up in it and it continued to pull power and make heat, enough to distort some plastic fuse holder until it finally blew the fuse (15 or 20A). Ever since that I fuse everything with its own power source; with the exception of my radar detector, it gets added onto another circuit, but I still think about it