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138 led underhood worklight (homemade)

posted May 07, 2016 23:02:45 by tony redolfi
besides making the 600 solder joints this light calls for,,,(hahaha) its super cheap to make around 25 bucks, and it should be way more powerful compared to any light I seen on the market, I just wanted something to light the entire engine bay up but not get hot like flood lights etc.. I checked all the math so it seems this is how it gets built or at least how im building it.

138 leds --- each 10mm 0.5W White 290,000MCD

DC Forward Current: 100mA

unit draws 4.6 amps total

3 x 46 array uses 138 LEDs / and 46 22ohms resistors

the power pack is 6amp 12volt

im still waiting on the resistors to finish it, but you get the idea,, rows of 3 leds down the entire tube,,, the tube I got at home depot for 4 bucks it was 8ft long and used for protecting florescent tube lights, the rows of 3 will connect to the 16g bare wire I ran down each side





[Last edited May 07, 2016 23:07:19]
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5 replies
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Noah said May 08, 2016 02:12:02
Impressive! A good underhood lamp that size is expensive,(and I'm cheap), this is a build I can see myself doing.
What's your board material?
Massachusetts, USA
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tony redolfi said May 08, 2016 03:24:07
thanks,,,,, at home depot in the plywood area,, they got 1/8 thick hardboard 2x4ft sheets for under 5bucks

the stuff works really well for something like this, I even made my own 10ft power wire,, I took a 16g red and black wire and heat shrinked that tubing over them.

the way you figure out the resistor size for you bulb is like this


you take the lights fwd volts x the number of lights in one array in my case it was

3.4 volts x 3 leds = 10.2 total volts

now subtract total volts with the main voltage to get your voltage drop

10.2 - 12.0 = 1.8

next divide your voltage drop into the led forward current in my case its 100ma (0.1 of an amp)


1.8 / 0.1 = 18ohms and 22 is the next highest available resistor from 18

so that how I got 22ohms resistors


heres a good link that helped me http://led.linear1.org/led.wiz

[Last edited May 08, 2016 03:26:48]
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tony redolfi said May 14, 2016 16:29:39
they didn't lie about the candle power in these huge leds!!!

this is just one led I got on a test board, its super bright, cant even imagine 138 of these at once


anyway I just got these leds in this morning and I'm waiting on my new soldering station that should be here in a few hours.

hopefully ill have this built by tomorrow



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Noah said May 14, 2016 17:12:18
😎👍
Massachusetts, USA
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tony redolfi said May 15, 2016 15:52:15
well it took about 8hours to build, its super bright,, just need to make up some mounting devices for it now

need sunglasses




[Last edited May 15, 2016 15:55:01]
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