The following is from another mc forum I'm on from a rider/electrician in response to an inquiry on wiring electrical farkles:
Low current stuff (radios with speakers are at the high end of this range) can run through a switch directly but anything pulling 10A or more (driving lights are a good example as are "real" horns) should be controlled by a relay tripped by a switch. Let the relay's heavier contacts do the heavy lifting.
The thing that most people get wrong in these projects is the wire run itself. Keep it short and direct (there is loss in any copper wire and, on a bike, there isn't any headroom to throw power away). Use the proper gauge wire (except for single LED panel lights, anything smaller than 16 AWG is a bad idea - 14 AWG makes more sense for larger loads) and make clean, tight crimp connections (if you're going to do a lot of wiring, bite the bullet and buy a real crimper - $50 isn't cheap but you won't wind up on the side of the road, at oh-dark-thirty, with a connector swinging in the breezes, either).
Tie stuff down! If it can move, it'll wear through, and a short can ruin your whole day. Cable ties are dirt cheap; use lots of them (cut the tails off cleanly - leaving them out is sooooo "rat bike" - and keep the cut ends close to the cinch - those cut ends can be surprisingly sharp).
Speaking of shorts, fuse that power supply at the source! If you have a 3' run from the battery to a horn relay and the fuse is at the relay, that's 3' of potential short looking for a place to happen. Fused next to the power source, the fuse should go "poof" before the bike does...
The ground is often the most abused part of any wiring scheme. I've seen elaborate power supplies that fed power hungry lights and then hit one sorry bit of wire tucked under a hose clamp somewhere. The ground or return line carries the full power load of the device. Do a poor job with the ground and you're throwing away power and making the device run poorly.
There are lots of aftermarket power distribution panels. If you're going to go nuts with accessories, use one of these panels to organize things instead of tying back to the battery or (worse) stealing power from some wire that happens to have +12VDC on it sometimes...
Color code the wires. At least use red for the hot side and black for the ground side. It'll pay off when you try to troubleshoot something or add yet another farkle. Make a drawing of what you did! Three months from now, you'll look at that wiring job and spend too much time trying to guess what goes where and why.
I think I need a pd bar........
Low current stuff (radios with speakers are at the high end of this range) can run through a switch directly but anything pulling 10A or more (driving lights are a good example as are "real" horns) should be controlled by a relay tripped by a switch. Let the relay's heavier contacts do the heavy lifting.
The thing that most people get wrong in these projects is the wire run itself. Keep it short and direct (there is loss in any copper wire and, on a bike, there isn't any headroom to throw power away). Use the proper gauge wire (except for single LED panel lights, anything smaller than 16 AWG is a bad idea - 14 AWG makes more sense for larger loads) and make clean, tight crimp connections (if you're going to do a lot of wiring, bite the bullet and buy a real crimper - $50 isn't cheap but you won't wind up on the side of the road, at oh-dark-thirty, with a connector swinging in the breezes, either).
Tie stuff down! If it can move, it'll wear through, and a short can ruin your whole day. Cable ties are dirt cheap; use lots of them (cut the tails off cleanly - leaving them out is sooooo "rat bike" - and keep the cut ends close to the cinch - those cut ends can be surprisingly sharp).
Speaking of shorts, fuse that power supply at the source! If you have a 3' run from the battery to a horn relay and the fuse is at the relay, that's 3' of potential short looking for a place to happen. Fused next to the power source, the fuse should go "poof" before the bike does...
The ground is often the most abused part of any wiring scheme. I've seen elaborate power supplies that fed power hungry lights and then hit one sorry bit of wire tucked under a hose clamp somewhere. The ground or return line carries the full power load of the device. Do a poor job with the ground and you're throwing away power and making the device run poorly.
There are lots of aftermarket power distribution panels. If you're going to go nuts with accessories, use one of these panels to organize things instead of tying back to the battery or (worse) stealing power from some wire that happens to have +12VDC on it sometimes...
Color code the wires. At least use red for the hot side and black for the ground side. It'll pay off when you try to troubleshoot something or add yet another farkle. Make a drawing of what you did! Three months from now, you'll look at that wiring job and spend too much time trying to guess what goes where and why.
I think I need a pd bar........