discodave

Quick question for the lighting experts out there. I have TONS of lights on my truck and ran them all to one switch, wired directly to the battery with a relay. I wired them up myself but had a buddy hook up the relay and stuff to the battery. I had the lights all on the other night and when I went to flip the switch to turn them off, none of them turned off. Kept flipping the switch back and forth and nothing, they just stayed on. I ended up having to disconnect the 8 gauge wire that was hooked up to the battery.


Any idea what went wrong? Bad switch? Bad ground somewhere?


Thanks!


(here are all the lights I have)

Feathermerchant

If a relay is overloaded enough, the contacts can weld together. Then it will not open. Ever.

Samuel Stainback

Yup, this is what happened. You have too much power going through the relay.

ADDcole

You should have 1 relay per lightbar normally, some smaller lights you can get away with combining them. Check with the manufacturer of the lights & see what voltage they are pulling & see what the recommend.

Feathermerchant

What amperage they are pulling.
Relays are rated for Amps just like fuses. So you can use your switch to operate several relays and spread the load to several relays. Or buy a relay rated for more load.

Samuel Stainback

The voltage is always going to be 12 since that is what the battery produces. The current (amps) is the important part. The number of light bars per relay doesn't matter so long as the total number of amps for ALL light bars connected to the relay does not exceed the current rating for the relay. And generally, you don't want to exceed 75% of the rated current load.

Also, you should have a fuse on the lead wire from the battery, BEFORE the relay, which should have only slightly more current capacity than the total for all the light bars.

ADDcole

ahh you know what I meant, amps/volts/watts, tomato/tomata, haha. Either way, way too many lights for 1 relay .

elricfate

I was just about to repeat this. This is accurate.

Samuel Stainback

If for some reason you don't know the AMPs for a light, but you do know the wattage: watts = amps x voltage. So the AMPS = watts / 12.

:-)

Kommander

Hahaha!! It's like the Ghostbusters ride!