Lights behind grill

Mike1220 · January 26, 2015

I'm going to ask what looks like an ignorant question, but bear with me it is to reinforce my point with someone that watts law still applies to LED light bars. If you buy a 180 watt light bar it should be about 15 amps and if you get a 300 watt light bar it should draw about 25 amps. I know they can be rated at 13.5 volts so it would be 13.3 amps and 22.2 amps. However there is no way a 300 watt light would only draw 14.5 amps, correct?

are you sure that the 300W at 14.5 amps is the 12V rating? I know that once you jump the voltage up to 24V the the amps go way down. The curved 55" that I'm looking to get after I lift my truck runs at 21.42A @ 12V and 10.71A @ 24V. The bar is 312W

tanner709 · January 26, 2015

I see a lot of companies quote numbers like yours, but how can you output 312W @ 12v with only 21.xx Amps?

312W/12v = 26A, my question is are they quoting theoretical vs actual numbers mixed, or what?

I could see a "312W" bar only using the 21.xx amps when it doesn't really output a true 312W.

Crf450r420 · January 26, 2015

are you sure that the 300W at 14.5 amps is the 12V rating? I know that once you jump the voltage up to 24V the the amps go way down. The curved 55" that I'm looking to get after I lift my truck runs at 21.42A @ 12V and 10.71A @ 24V. The bar is 312W

That brings up other questions mike. LOL

Can a bar be rated at 12 to 24 volts?

Wonder if it was rated for 12 to 24v if the amps would change to stay 300 watt draw?

Crf450r420 · January 26, 2015

I see a lot of companies quote numbers like yours, but how can you output 312W @ 12v with only 21.xx Amps?

312W/12v = 26A, my question is are they quoting theoretical vs actual numbers mixed, or what?

I could see a "312W" bar only using the 21.xx amps when it doesn't really output a true 312W.

That is why through in the 13.5v for alternator charging and I can see rounding a little to get a good number for selling. Who would advertise a 297.3 watt light, but there is no way it should be off by 10 amps or 40% draw, right?

allterrain14 · January 29, 2015

Tester came in. Tested the standard 180w 30" Cree. It pulls about 10amps. Did some research as my physics is a little rusty. Ohms law only applies to a single median in a circuit. There are many different materials and medians on a light bar. In addition ohms law doesn't apply when using things like capacitors, diodes, etc... Diodes, especially LEDs that emit heat do not follow Ohms law either due to the changes caused by heat.

Wormydog1724 · February 10, 2015

_{Are the diagonal brackets 2"x2"?}

ewhite6 · February 12, 2015

I just bought my 30" Double Row Combo pattern with wiring harness for $90 shipped! That's a steal!!!

Curious where you got the deal and how you like them so far.

Crf450r420 · February 12, 2015

Tester came in. Tested the standard 180w 30" Cree. It pulls about 10amps. Did some research as my physics is a little rusty. Ohms law only applies to a single median in a circuit. There are many different materials and medians on a light bar. In addition ohms law doesn't apply when using things like capacitors, diodes, etc... Diodes, especially LEDs that emit heat do not follow Ohms law either due to the changes caused by heat.

I think the last one we came up with as it. The rate it by the LEDs so 60 3 watt LED you can get 180 watt, but if not driven that hard you don't. Then 60 5 watt LED is 300 watt, but they are driven much less. Some will put off more light at the same power. It is also possible to get one that is rated higher and puts of less light than the lower rated based on how they are driven. Guess it's best to shop by actual lumens they output.

boone9 · March 11, 2015

Here's a 32" bar behind the grille of a sierra A/T

Hey, sorry to bother you, could you post a picture of what it looks like during the day with the bar off. Im having a hard time deciding what to do and im yet to see a picture of an AT grill with light bar behind it. Thanks

Wormydog1724 · March 11, 2015

162EFF4F-5662-4942-ACF1-800FCA0E7208_zps

Wormydog1724 · March 13, 2015

Had been using the remote switch for my light bar and decided I really didn't care for it. Would rather have a switch. So I messed around tonight and came up with this.

Crf450r420 · March 13, 2015

I'm starting to want a switch and this gives me hope I can find a way I'll be okay with it.

Wormydog1724 · March 13, 2015

Just make sure you drill the hole in the middle. Lol I'm an idiot.

arkenzo · March 13, 2015

Which bar and brackets did you use for your setup? Looks great!

Wormydog1724 · March 13, 2015

Which bar and brackets did you use for your setup? Looks great!

I kind of 'country rigged' a couple brackets from a bunch of spare parts and junk I found in the shop. They're sturdy but I'm going to rework them when I have a free weekend to maybe lower it another 1/4" or so. I'd like to get some nice ones like that one guy on here makes, but I don't really want to spend that much cheese on something I can make from scratch. Just took some thinking and planning to come up with something from what I had laying around.