Is your light bar draining your battery?

There are many reasons why your newly installed light bar might be draining your battery, we suggest you do the following checks:

  • Connect your light bar directly to the vehicle battery or another DC voltage source. If you going to use a power supply, make sure its voltage output is within the light bar’s specifications. Also, make sure it can supply the maximum current your light bar draws.
  •  Use a wire gauge that matches or exceeds the maximum current of your LED light bar.
  •  Fuse power wires to the expected current draw, not the wire size.
  • Use an automotive switching relay if the light bar draws 10A or greater.
  • With or without a relay, use a cab switch rated for at least 10 amps.
  • Secure the relay to a suitable location, and test the light to make sure the circuit works.
  • Use waterproof wiring connectors. Check for these at a local marine shop.
  • Avoid unnecessary splices, but use a snap-in connector at the light bar to ease removal.


Read common questions and answers on LED light Bars



im replacing 4 light bars under continental (brand name) running boards on my p/u. I thought i had them grounded right, but they’re draining the battery. Also, i have a 20amp fuse for parking lamps etc. what gauge wire should i be using?
Are your light bars hooked up to a switch or relay of some sort so they turn off? The only way I can think of that they’d drain the battery is if they were constantly on.
I’m not sure of the relation between the fuse comment and wire gauge question. Are you tapping into the parking lamp fuse for other lighting?
You might also have a small short somewere in your wiring. And if you fuse is too big then it won’t pop and that will drain your batter very quickly.
 I think you’re turned around . Not having the light bars grounded properly would not cause a drain on your battery . What indicates to you that they’re draining your battery ? Do you turn them completely off when you’re not using them ? How long does it take to drain the battery and to what point ?

You mean the stock headlight-circuit fuse on the vehicle is 20 amps ? Is that the circuit you tapped into for the light bars ? Are you asking what gauge wire you should use on the run between the light bars and the fusebox or the stock parking lamps and the fusebox ? Where did you tap power from ?
This is all quite confusing .

The lights not being grounding is not going to be your problem. If anything, the lights not being grounded should tell you it’s not the lights b/c there wouldn’t be a complete circuit. I suspect something besides that lights.

Here’s something you can do. Get a DMM (digital multi meter) and set it to read current. Remove the ground from the lights and attach that wire to one wire from the DMM. Connect the other wire from the DMM to ground and read the current. If there’s no current, that’s light isn’t your problem so go to the next one.

My husband did a horrible job of wiring underneath the frame, and i knew one light bar was not working. I re-wired it across the frame, and in the process i blew the factory 20amp fuse. anyways, when i did get them all working, the next day the truck battery was dead dead dead. It took a charge, and i thought perhaps they needed to be grounded better (to the frame)