Wiring Hi/Lo Beam

[farmerj]

OK, showing ignorance here but need someone to confirm what is probably obvious.

I added a 6" light bar to my XC a while back, with harness and relay. Now I am upgrading to the LED and want to add in the Low Beam.

I purchased a new SPDT switch (two position) to replace the single-throw that I was using to run the light bar, thinking that I would just run a wire from the switch to the low beam.

But that's not how it works, right? Do I have to run a second harness and relay back to the battery for the Low Beam (as well as the high beam)? Or is there a way to simplify?

Thanks,

Jeff

[farmerj]

Another way to ask this question might be, "Do I need to use relays to run lighting or can a powered wire run from the battery to the switch and from there to the light?"

[Neil E.]

Really depends on how high the lighting load actually is. Most aftermarket lighting kits always include a relay. This is because the supplier has no way of knowing if your headlight switch can carry enough current.

Hook it up like this: lightweight lead from your positive supply goes to common on your toggle switch. Power comes out one side going to the High Beam Relay coil. Power comes out the other side going to the Low Beam Relay coil. Both relay coils get grounded with lightweight wire from your negative supply.

Heavy wiring goes from positive supply to both relay contact inputs. Heavy wiring out from the contacts to the respective high or low beam. Heavy wire from each light to your negative supply.

[farmerj]

This is making sense, Neil.

So yes, both high and low circuits each need their own relay. And if my switch could handle the load, I don't need relays. Right so far?

The light is 45W and the switch is 6A = 72W. So in theory, I can go w/o relays...

I already have a high beam relay in place from my other light. Could I try the low beam without a relay, using a fuse to protect the system if it doesn't work? (my switch was cheap).

[Neil E.]

Based on those specs you should have no problem with the low beam being handled only by your switch.

[farmerj]

And a last set of questions (I think!) about the "positive supply" source.

(1) I've hooked my grip heaters to ac/yellow as you suggested in another thread. Is this because ac is more efficient than dc?

(2) Should I hook up my dc lighting to the battery, or to a hot wire directly out of the regulator/rectifier - or does it matter? I want to minimize draw on the battery.

(It tends to drop voltage as I ride, I'm in tight singletrack and not in the upper rpms much).

Thanks for your contributions on this forum, Neil.