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? asked in Home & GardenDo It Yourself (DIY) · 9 months ago

LED light question. How can I make it run off battery.?

 in I'm an electricians apprentice and I recently was asked to demo out some pack lights on the outside of a building. I kept one of the massive LED lights inside the wall pack. I cut off the mogul screw exposing the input hot and neutral wires and I attached a ground and connected a piece of SO cord with a cord body so that I could run it off 120v AC but I noticed it had a sticker saying the light runs off 38-42v DC at .7 amps I believe. Is there a good way to run this light off of a battery and still be able to carry the whole setup in a hiking bookbag. I want to carry it into the entrance of petty John's cave in Georgia so I can take really good pictures using the light. 

Update:

I don't believe just putting a bunch of batteries together would work because the amperage would exceed what the light is rated for and burn up the LEDs quickly 

Update 2:

The LED light has all the control electronics embedded in a plasticy rubbery tray which makes accessing the downstream side of the transformer impossible so I won't be able to power this particular LED light with a battery I will just keep it how I have it wired up for mains voltage which could be 120-277v AC. Lol oh and Steve just stay out of it. Go back to your desk job you obviously have no idea how the real world works. 

Update 3:

I'm just going to get a lithium generator to power the light that way I don't need dc voltage I can use the ac voltage the small generator puts out

5 Answers

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  • elhigh
    Lv 7
    9 months ago
    Favorite Answer

    The light's control electronics should still be in there, if you can connect to the power supply downstream of the power conditioning hardware that converts from 120v to 38-42v (it may be a simple transformer) and from AC to DC, then you should be able to simply connect 38-42v worth of batteries and the power board will modulate the amp draw.

    Barring that, you could hog out the original control board and wire in a boost converter.  Dial in the voltage and amperage that give the best lumens per watt and boom, done.  Boost converters are available all over the internet, it's easy and fun.  My son and I built a buck converter adapter to create a corded power supply that plugs into his (usually) cordless DeWalt string trimmer, so it could be powered by our electric tractor.  Easy to do.

  • STEVEN F
    Lv 7
    8 months ago

    You are a BAD LIAR. There is NO WAY you could be even a 1st day electrician's apprentice an have any need to ask BASIC questions about electricity.

    In addition, NO ONE asks anyone to demo anything without SHOWING them how to demonstrate it.

  • Girlie Electrics
    Lv 7
    9 months ago

    You dont get it.

    The current draw is governed by the resistance of the load.

    Unless you short out the lamp, it will draw no more than it needs to. (.7A)

  • Anonymous
    9 months ago

    Get a 42v battery from an impact driver.

  • Ghost Of Christmas Past
    Lv 7
    9 months ago

    You could make up a pack of 26 AA batteries arranged in series.

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