How to choose the right LED light bar

Kris11

TJ Enthusiast
Joined
Nov 5, 2015
Messages
100
Location
Toronto, ON
So for Spot lights vs Flood lights its pretty simple. Spot lights will throw light far down the road (1000 feet on average) but in a focused beam style so it wont light up the sides of the road very much. Flood/Fog lights will spread that beam out so you can see the side of the road but not as far as the spot lights (500 feet on average). I attached a simple picture to help you guys see the difference. LED bars will usually be 30° Spot and 60° Flood so I attached a picture below of both beams.

If we are talking about LED's Lumens is basically amount of light output. The more Lumens you have the more light you will throw. While I was looking at different LED bars some had 10,000 Lumens and others had 20,000 Lumens. I wanted even brighter so I looked for one with 30,000 Lumens. But they come at a cost of watts and they are more expensive then regular LED bars. Other LED bars will only use on average like 200 watts. So my bar will draw a little more power because its a 300 watt bar. Now you have to convert watts to amps to make sure your stock system can handle it.

I know on my 2006 Jeep TJ I have a 117Amp alternator. To find out how much amps you will draw with your LED bar you have to do the math. The formula is Watts divided by 12Volt because you have a 12Volt system. So for example since I have a 300Watt LED bar I have to do 300Watt divided by 12Volt and that equals 25Amps ... So my LED bar will draw 25Amps of power. I will be ok because I have a 117Amp alternator.

I also have other lights on my jeep including 2 100Watt spot lights and 2 100Watt fog lights. Using the formula above my 4 other lights will draw 33.33Amps of power from the 12Volt system. After adding all of them up I will have a total draw of 58.33Amps when I have all of them on. I will be ok but some people may have different alternators and different numbers (watts, amps, etc.). I'm no professional but I have worked with electronics and robots and what not since grade 9 and im now in college so I know my fair share. Hope this helps! If anyone needs any help please feel free to send me a message and Ill give you my 2 cents.

flood_vs_spot.jpg


Here is a write up I did of installing my 50" LED Light bar:
50" LED Light Bar Write Up
 
Last edited:
  • Like
Reactions: Francesco.com
You forgot to factor in a power factor, I like to use either .7 or .8, so the 25 amps is more like 30-35 draw. I try to just think of it as efficiency and at those kind of amps, properly rated relays are important. Good read, Tim