Need help with light bar wiring

Is that really the operating amperage draw? Ideally you don’t want to running constantly at %80 load capacity.

In house wiring (romex, bx, conduit) the NEC amp ratings are:

14awg used on 15 amp circuits
12awg used on 20 amp circuits
10awg used on 30 amp circuits


If it works fine connected directly to the battery I’d suspect the auxbeam or the wiring/connections to the light.
What kind of connectors did you use?

 

It also depends on the length of the run as there will be a voltage drop further he runs it. There are a lot of online calculators for looking at this. One thing even though it can handle it, I really think it’s not a good idea to run high amp circuits through the bulkhead, especially as you can keep them small with relays and when you’re making bundles of them for various accessories.

 

it’s rare that I will have all lights turned on at once so I would never be pushing that load capacity

 

As the lights are working when hooked up directly from the battery, did you try it with the cable you put together or just the shorter original one?

it’s also good that you’re not grounding the switch panel through the frame.

 

Which is why you always upsize wiring….I would have used 12awg for that. You design for max load.

Voltage drop is negligble on such short runs like on a vehicle unless you’re wiring up high-draw or voltage-precise equipment.
In your house there are runs far longer than a vehicle that are fine.

The problem with vehicles is relying on chassis grounds and poor quality-or executed connectors.

 

I think you’re right, OP mentioned using 14 gauge, but even 10 feet of it can drop the voltage just a bit below 12v with a 14amp circuit, but I wouldn’t think that the lights would be that sensitive to it. It sounds like the relays in the light switch are not good for it- i’m using an inexpensive light switch to run mine as well, but mine go through a standard relay and work well.

 

Is the noise occurring with one light on or only all of them? ….(1 to 7 lights?)

I don’t know if the auxbeam is like the spod or switch pro with solid state relays….I’d guess it’s not because it’s a much cheaper controller.

Since it works fine direct to the battery I’m suspect of the auxbeam and connectors.

The 14awg will work ok enough, just not ideal….again voltage drop to a light with less than 20’ of wiring is being overly ocd.



I have a voswitch unit that I have not yet installed, it has similar keypad switches but regular electro-mechanical relays inside the box.
For now the BD 30” S8 light bar in the bumper is wired with the BD kit and a temp mounted toggle switch…..works fine-looks shitty!
Need to find the motivation to install the controller, powertay, mrcb ………etc.

 

You will likely need to use a relay so that your switch is not carrying the load of your light bar. Take a look at this
https://extremeledlightbars.com/how-to-wire-a-relay-for-off-road-led-lights

 

The noise was worst when I wired the light bar straight to the auxbeam(with 14ga), Right now instead I’m just using the original harness(has relay built in and gets power direct from battery) included with the light bar (14ga) and the switch wire from that harness goes to the Auxbeam switch panel. The noise does not seem as bad when wired this way and goes away after about 10 seconds.

 

the lights are all wired together so they turn on at the same time. And as far as I can tell the whine is coming from each light not any one in particular

The auxbeam does have solid state relays and fuses built in. But I’m starting to think that it is the problem here just because it is a cheap switch panel.

I don’t think voltage drop from wire length is an issue here, I have not even exceeded the length of the included harness.

 

You’re probably right, I purchased a inexpensive one also, but it doesn’t have an issue like that.

 

lots of asterisks here though.

NEC's specifications are for alternating current, household general purpose circuit use only. it also doesn't contain all the derating factors that can be present in specific conditions that contain high temperature, exposure to elements, or applies to dedicated loads. there's also no distance requirement within that portion of the NEC. later on in the wire type section, code further specifies derating factors, as well as current drop over distance, which can increase the minimum conductor sizing for the expected load

you're correct about the 80% rule though. that follows a/c or d/c circuits, as it's important to leave space for fusing deviation and startup inrush.


in this case, we're dealing with direct current, which is far more effected by voltage/current/distance. despite whatever the manufacturer supplies, it's not entirely uncommon to run a larger gauge up to the supplied wiring in order to decrease the voltage drop/current sag over the distance ran.

for starters, a guide like this is helpful to follow

 

My guess is it's the lightbar. I know it doesn't make sense that when you hook it up directly to the battery the whine goes away. That logically points to the switch. But I highly doubt it's the switch that's causing it. Probably something inside the lightbar that's drawing power down. I have seen this happen before.

I also have a lightbar wired directly to a garmin powerswitch. Contacts are rated for 30amps each, or 100amps total. It gives off a whine for about 10 seconds when turning on. I use a common ground bus for all my auxilliary devices and there's no issues with that. I connect a different light with similar specs to the same contacts and no whine. Have to pull my bumper to replace the lightbar so I just leave it. Can't hear it when the truck is running, and like I said it only lasts a few seconds.

Isolation relays are redundant if the switch contacts can handle the load, and the wire size is sufficient. Your original line of thinking of having the switch so you don't need a mess of relays is one of the main reasons those switches exist in the first place. You should only really isolate your circuits if you need to limit the current at the switch per the specs, otherwise you have extra wires, points of failure, and troubleshooting that isn't necessary. Most of these modern switch contacts are rated the same as automotive relay contacts anyway, so again it's redundant.

Lots of places include relays in their wiring harnesses because they need to provide you with a means to use them without requiring a fancy switch panel, and often those come with cheap switches that can't handle the load.

 

I’m going to reach out to Baja Designs about the lightbar and Auxbeam about the switch panel. I do think the Auxbeam is the issue here though. Best case I just have a defective Auxbeam and i’ll get a new one through warranty, I don’t see that being the case however.

I might just have to upgrade to something better like a switch pro if I can’t solve this otherwise. Because I do want to be able to run everything through the switch panel with only one battery connection.