How many watts / amps for LED light bar?

   / How many watts / amps for LED light bar? #1  

Timmer92

Member
Joined
Dec 9, 2019
Messages
48
Location
Minnesota
Tractor
Kubota L3901
Hi all,

I take delivery of my Kubota L3901 next week. I have a project I want to tackle immediately, and would like to have all the parts here ready to go. I want to add a 12-20" light bar to my ROPS. I am aware there is a prewired worklight connection. Based on my research, that is connected to a 10 amp fuse. I can find LED lights in the 75-125w range, which by my calculation would be up to 10 amps, and therefore would work on that connection. At the same time, there are many units out there in the 150-350w range or even bigger. I am guessing if I'm going to go through the trouble of adding a light, I don't want one that is under powered. I obviously can go with a bigger one and connect it directly to the battery with the appropriate fuse. Given that very few have specs for lumens, watts is pretty much the only measure I have. Any advice on whether I should go with a bigger wattage unit?

Just this fall I was planing rye with the provided headlights on the Kubota I just traded and I think I would have had more luck with flashlight! I would like to do it right.

Thanks!
 
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   / How many watts / amps for LED light bar? #2  
I would think that the 75W LED would be plenty enough! We only have one 50W that lights up our yard and that’s very bright. We have 20W in our cattle shed and it’s like daylight in there nearly. I certainly wouldn’t worry about going any higher
 
   / How many watts / amps for LED light bar? #3  
Watts for an LED is an indicator of power used or required power supply. For your tractor you can divide that by twelve to get the current rating (watts=volts X amps). Since LED lighting uses power more efficiently than incandescent lighting a watt of power feeding an LED will generally give you far more illumination than a watt of power feeding an incandescent. I would not expect to power a device requiring ten amps from a ten amp fuse. That leaves nothing for initial surge current. Either power a relay from that fuse or figure on powering about five amps of lighting.
 
   / How many watts / amps for LED light bar? #4  
Maybe you need to know actual current (amp) values instead of going by watts... As a example this 100 watt, 20 inch light bar puts out 9,600 lumens and only draws 7.33 amps as stated in its specification sheet...

2" Curved Off-Road LED Light Bar - 1W - 9,6 Lumens | Super Bright LEDs

You really need to find amperage draw if you are limited by existing fuse size.... The watt values of light bars and leds can be misleading...

Dale
 
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   / How many watts / amps for LED light bar? #5  
A light bar may be overkill. I have a single round LED lamp forward-facing on my ROPS and it's enough to light up the area like daytime. I have a second light facing rearward. I put them on separate switches, both tied into the work light wiring under the left fender. Each light draws 1.4 amps at 12V.

My tractor LEDs are from 2011, and newer LEDS will be more capable. I put two Rigid SR-M lights on my boat t-top and they are ~2400 lumens and 2A (per light). They are great for coming into my creek at night. I think they would be too bright for my tractor, but it gives you a good idea of the lumens and amperage ballpark. I'd say you should have more than enough light out of 2000-5000 lumens and 2-4A.
 
   / How many watts / amps for LED light bar? #6  
Watts for an LED is an indicator of power used or required power supply. For your tractor you can divide that by twelve to get the current rating (watts=volts X amps). Since LED lighting uses power more efficiently than incandescent lighting a watt of power feeding an LED will generally give you far more illumination than a watt of power feeding an incandescent. I would not expect to power a device requiring ten amps from a ten amp fuse. That leaves nothing for initial surge current. Either power a relay from that fuse or figure on powering about five amps of lighting.

Timmer92, welcome to TBN!

+1 on most of Roadworthy's comments, except that I'm sure you'd be fine with 90w of LED, drawing 7.5A on the existing 10A circuit. Rather than a single light bar, if that is what you have in mind, consider adding two 45w LED floods, one on each side of your ROPS. That will give you more flexibility in aiming the beams. And more than enough light for most any work in front of the tractor after dark.
 
   / How many watts / amps for LED light bar? #8  
Lightning bugs in a mason jar?
_______________________________
I wanted to make a smartass reply too, but restrained myself. Good thing, cuz your reply was way better than mine would have been! :)
 
   / How many watts / amps for LED light bar? #9  
Perhaps there is an issue here translating between actual watts of electrical power and some sort of equivalent brightness comparing to incandescent bulbs, as huddlewalt mentioned. I kinda think an LED assembly that actually takes 350 watts of electrical power, or even more, will create all kinds of additional problems, such as igniting your neighbor's siding, disrupting local air traffic, and changing local weather.
 
   / How many watts / amps for LED light bar? #10  
LOL!
 
 
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