How to Proper Headlight Wiring?

[John Haggerty]

36v DS. I have 36v to 12v converter, fuse block and ground block now mounted. I've been running from the 12v post. To hook up the converter properly, do I come off the ignition switch or wire direct to the 36v post? Seems like I'd want the converter switched vs. always being hot.

Thanks,
John

[yawood]

I agree that it is better to have the converter switched rather than hot all the time. However, it is best not to connect it straight to the key switch because you run the risk of sending too many amps through the key switch.

The best way is to use a relay such as this one from Mouser Electronics. The positive 36V (from the main positive of the battery pack) to the reducer is broken across the main terminals of the relay. The negative of the reducer goes to the main negative of the battery pack.

Note that the negatives always go straight back to the batteries and NOT to the cart chassis.

A wire from the "cold" side of the key switch (i.e. the side of the key switch which has power only when the key is on) goes to one side of the relay secondary. The other side of the relay secondary is connected to the 36V negative (wherever you can find a convenient negative terminal).

So, what happens when you turn the key switch on is that power goes to the secondary side of the relay which switches the main coil on and delivers bulk power to the reducer directly from the batteries. The key switch only carries the current necessary to turn on the relay.

The only other thing you should do is put an in-line fuse in the +36V cable that goes to the reducer (via the relay). This fuse should be as close to the battery as possible. The photo shows the way I have connected mine on a 48V cart.

Your headlights and other 12V accessories just come off the reducer (probably via your fuse block). The reducer effectively becomes the 12V "battery" that runs all the accessories.