Lots of threads on a related topic from way before my time here: unless you've added a relay-based solution to your headlight wiring, you're at risk of problems with your starter switch
For cheap, wire the aux lights to a relay -- relay to the battery for power and to a switched wire for triggering the relay.
For more money, and more flexibility if you have the need for it: wire them to a switched fuse panel (I use the Eastern Beaver PC-8
I went the fuse panel route, as I have a bunch of other stuff wired up to the switched fuse panel. FWIW, I also added the EB headlight relay kit
. You could do it cheaper on your own, but I found it worth the price of not dorking around with it myself.
Agree with all inputs: don't use existing headlamp circuit. I have a switched relay to an aux. fusebox; it's a fun installation and draws power from the battery via the switch ( I would forget the light was on when the key was out This solves the problem: no ignition, no power). I bought cheap LED spots on ebay and they have been perfectly waterproof for 3 years. They are attached to my engine guards.
The relay will have 4 points on it, marked 30, 87, 85 and 86. That is kind of cryptic, isn’t it?
30 and 87 create the switch to your lights. By default this switch is open, so the current cannot get from the battery to your lights.
30 – is your power source for your light. It connects to the positive (+) side of your battery or to a switched power source that only gets power when your ignition is on.
87 – goes to the positive side of your LED lights.
85 and 86 use electrical current to create a magnetic force, which then closes the 30 to 87 switch and allows the electricity to flow to your lights. Without this current, no magnetic force is created, so the 30 to 87 switch stays open, and your lights stay off.
85 – connects to the power source that you want controlling the switch. For example you could splice a wire off your high beam wire or off your backup light wire
86 – connect to a ground.