Hi I'm new and I'm looking into installing a 200-500W amp in my 2003 Mazda MPV trunk. For the power supply, I was wondering whether I could splice into an extra 12 V power supply plug (like the cigarette lighter) in the back of the car for the power instead of wiring from the battery in the engine bay. If this is possible, could also tell me where to put the fuse (and what type?)? Would it be between the car's power supply to the 12V outlet im using or the wires from the Amp to the 12V power supply? Thanks
Won't work. You need a much larger wire to carry the current required for the amp than what that power supply can provide. You need to run a wiring kit and install the fuse about a foot from the battery.
wire size is based on how much current the wire can handle, over a given distance, without melting. the car is wired with, at most, 18ga wire throughout for accessories and such. Most of the time, closer to 20-22ga. this wire isn't made to handle an amplifier, which can draw up to 60A for a 500 watt amplifier. a cigarette lighter usually can handle maybe 2A of current, so you see the problem.
for a 500 watt amp, you really need to run 4ga to the amp directly from the battery's positive terminal, and ground the amp within about two feet of it's location to bare chassis metal. it's really not as hard as it sounds. www.knukonceptz.com has 4ga amp wiring kits for about $25-30 that have all the cable and RCA interconnects you should need.
ooh thanks! by the way, what are the RCA cables for? Don't I take the exisitng wires from the stock speakers and attach those to the amp and from the amp, I put new wires to the speakers? (I'm not installing a sub just yet)
oh and, sorry for the double post, but for the remote wire, is that ok to hook it up to the cig lighter because it doesn't turn on till the car's ignition is on and that's what I want for the amp also?
ah you're using the stock head unit. in that case, you won't use the RCA cables, and most modern amplifiers don't need the remote line if you're using speaker level connectors for signal. the amp uses those same wires to "sense" when to turn on. otherwise just connect remote if it's needed, to any +12V ignition line so the amp turns on with the keys in accessory or start positions.