What gauge wire.....

-
inkjunkie

inkjunkie

Well-Known Member
Joined
May 24, 2009
Messages
17,416
Reaction score
3,094
Location
......
Will be taking the snippers to my bike here soon...harness looks like a birds nest. Will have an H-4 style head lamp with a 60/55w bulb. In order to run the harness thru the frame all the wires need to be kept as small as possible...and even then they still might not all make it. Anyhow, headlamp will have a relay on it, plan on using both of the contacts, one for the low beam the other for the high beam. If I remember correctly to get amps from watts it is watts/volts...which in my case will put the load at a measly 5 amps. From relay to headlamp will be about 4' of wire. All the wire charts I have ever seen say 18 Gauge....In crackedbacks kits that he is offering Rob makes mention of 12 or 14 Gauge from relays to lamps.....Question is how heavy of a wire is really needed?
 
Keep in mind that since you are using relays, the size of the wire that activates the relay can be smaller than a wire that carries all the amps for lights normally.
 
Doug you are not talking about wiring a 500 ft tall rocket ship here, so the difference in wire cost is minimal. I would run no 14 if you have the room, 16 ga would be big enough.

"Opinions vary" as to charts: Between 5--7.5 A draw, no16 will be less than 2% drop in 7.7--11.5 ft of wire. Note that this is total wire, as in a boat which does not use a "frame" ground.

Wire-Gauge-Guide.jpg
 
You can run 20ga wire to trigger the relays.

Run 14ga from battery/source to relays to bulb.

I build my stuff to minimize voltage drop, that's why the 12ga wire gets used. I also don't have to contend with sizing restrictions
 
TrailBeast said:
Keep in mind that since you are using relays, the size of the wire that activates the relay can be smaller than a wire that carries all the amps for lights normally.
Click to expand...
Switches have 16 ga off of them. If I can mount the relay in the bucket it will be helpful is squeezing it all in there.

67Dart273 said:
Doug you are not talking about wiring a 500 ft tall rocket ship here, so the difference in wire cost is minimal. I would run no 14 if you have the room, 16 ga would be big enough.

"Opinions vary" as to charts: Between 5--7.5 A draw, no16 will be less than 2% drop in 7.7--11.5 ft of wire. Note that this is total wire, as in a boat which does not use a "frame" ground.

Wire-Gauge-Guide.jpg
Click to expand...
Not worried about the $$....have the wire already. Just concerned about voltage drop. At most the distance form the relay to the lamp is going to be 4'.....if I put the relay in the bucket it is only going to be 4"....but then it will not be running thru the frame space will not be a problem.....
crackedback said:
You can run 20ga wire to trigger the relays.

Run 14ga from battery/source to relays to bulb.

I build my stuff to minimize voltage drop, that's why the 12ga wire gets used. I also don't have to contend with sizing restrictions
Click to expand...

Am hoping to be able to squeeze at least a 14 GA if I have to mount the relay out of the bucket. Might look at eliminating a couple of the indicator lights...don't really need the neutral safety light....the signal module is going to be in the middle of the bike....wondering if I can use one indicator lamp for both sides of the turn signals...put a diode in somewhere perhaps?

Really like to avoid having the harness hanging out in the open like it is. The area where is has to run, if I can not get it all in the frame, is down below the fuel tank so it is more or less exposed...and looks like crap....

Either way it is going to be nice to not have to worry about the multiple splices in each wire. Ever since I have owned this thing it has always been just patch work to keep it running. Every time one of the handlebar switches crapped out I would just splice into them where ever it was easiest...hence the nest effect....
 
After digging into the bike yesterday came to the conclusion that I can not do what I had planned..
 
You must log in or register to reply here.
-

Back
Top