I am helping a friend put some amps in his car. There is an amp in his trunk that is fully connected and working. We are needing to install two 90 watt amps also. I know how to ground them, but how would I go about getting the power and remote wires to them. I know how to run them but getting power to them is the problem. And for the remote should I just split the 1 remote wire off the deck to all three amps??
You'll probably start by changing the power and ground wire sizes to accomodate 3 amps now instead of 1. Add up the total watts and upgrade to the proper size wiring. Upgrade the power wire fuse as well. There are a lot of distibution blocks to pick from that will accept the power wire and split wires out to the amplifiers. Get one that is fused, and place fuses in it that are appropriate for the size wires that are feeding the amps.
Often, mostly for a clean install, a grounding block (unfused) can be used too. The ground wires for each amp would match the power wires that feed them, and the main ground to chassis would match the main power wire gauge.
A lot of people have no problem splitting a remote to 3 amps. Mathematically, the sum of the draw should be well less than the amount that would harm the deck. But I've often heard that for more than two amps you should use a relay to split the turn on. If you want to use the relay, use a common Bosch and connect as shown here. Turn on wires can always be connected to the car's 12 volt switched supply as well as the head unit. The difference would be that the amp would turn on when the car is turned on. Connecting one amp that way, with two split to the head unit, would get you around that "3 amps need a relay" rule without having to use a relay.
Look to the left column here for more info on power/ground wire sizes appropriate for the current they have to handle.
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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
relay would be nice but i can't see the circumstance where it would be nedessary
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car 1 = alpine 9807, mtx 404+mtx 311d, polk speakers, kappa 10"
car 2 = pioneer 7700, kicker 400x1, kicker 60x4, 10"compvr x2, kappa speakers