Jersey_Devil

I recently wired up a 20" Hanma L.E.D. light bar, I had an in-line fuse that I bought but when I was wiring it up I couldn't find that or the other switch i bought..... So I wired it up using the only accessory relay left at the store I think it was a 44 amp, but not sure..... Should I be splicing the in-line fuse in also or amniotic fine with just the relay switch? Thanks in advance!

HAPPY JEEPIN EVERYONE!

JK-Ford

The relay offers "0" circuit protection. The fuse "IS" the circuit protector.

Jersey_Devil

Thanks! I'll go buy a new iin-line fuse tomorrow..... Should I be putting the fuse between the battery and relay or between the relay and the light?

Freewill

The fuse is protection against heat and fire. It goes as close to the power source (battery) as possible.

The relay is a control. It offers no protection but it controls the power along a big cable by using a small wire and switch.

The power cable should be fused according to the size of the cable.

The relay's small control wire also needs to be protected by a fuse or breaker but it will be a much smaller fuse than the big power cable uses. If an existing fused circuit is used to trigger the relay, a second fuse is not needed.

Jersey_Devil

So then I need two fuses? One for battery side and another on the accessory side?

Now I'm getting confused......

Here's the light is have http://www.hanma-auto.com/products/d...light-bar-120w
So should I be getting an 8amp fuse for between battery and relay?

Freewill

With a relay you have two circuits or cable runs. One carries the power from the battery to the lights. That one has a relay along the way somewhere. This is usually a pretty phat piece of wire.

The relay is controlled by another cable run. It has the switch along the way, and the switch triggers the relay which turns on the lights. This can be a thin piece of wire because all it does is trigger the relay.

Both of those cable runs need a fuse. The phat one gets a dedicated fuse at the battery. The thin one also needs a fuse (ALL cable runs need a fuse), but if you grab a live auxiliary circuit like tapping off the lighter then that run already has a fuse. If you run a dedicated wire back to the battery to trigger the relay then the trigger wire needs its own fuse.

For example: An 10 gauge cable comes off the battery with a 30 amp fuse and goes to a relay, and then on to the lights. Another cable, maybe 16 gauge, comes from a hot power source, runs to the light switch, and then runs to the trigger contact on the relay. This one needs a 10 amp fuse if it goes to the battery but if it comes from, say, the lighter, then another fuse is not needed because the lighter is already fused.

This is standard wiring stuff regardless of what you're hooking up.

I noticed the Web page for the light has a glaring error. It says: "Current draw 8A @ 12V, 16A @ 24V ". That's backwards. Should say: "Current draw 16A @ 12V, 8A @ 24V ".

Hope this helps. Wiring is hard to describe with just words. ronjenx has posted some really nice wiring diagrams. Maybe you can find one of his posts for running lights with a relay.

JK-Ford

Sorry for the confusion? Yes you need two fuses. The fuse for the accessory circuit only needs to be 3 amp. This is the power supply to the switch. The other fuse between the battery and relay needs to be 10 amp. 120 watts / 12 volts = 10 amps.

Freewill

Hmmm. Think I had that wrong JKFord. Believe it was you that posted some nice schematics and wiring diagrams.

ronjenx

Yeah, my posts had more to do with how to get fused/switched power out of the TIPM.

I have always advocated having a fuse close to the battery, based on wire size, any time an added circuit leaves the battery, much like you have done in this thread.

The point to remember is, the fuse protects the circuit, not the appliance.

Jersey_Devil

Thank u! That really cleared it up for me! I do know some things about wiring but u guys definitely just gave me a good lesson! I really learned every other system of an automobile except electrical, and transmission.... Never got into learning them.... Never had a teacher. :-(

Thanks for the lesson!

HAPPY JEEPIN EVERYONE!