Troubleshooting a homebuilt light system.- Mtbr.com
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  1. #1
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    Troubleshooting a homebuilt light system.

    My current light setup is fabricated from old BLT Spectrum light bodies (Used to take MR-11 bulbs). There is now a custom faceplate that mates Carclo 20mm optics to a heatsink slug that is pressed into the body, and the driver sits in the cavity behind it.
    Troubleshooting a homebuilt light system.-untitled.png
    The battery pack is 4 Ultrafire cells in a 2s2p configuration. No balance circuit

    The problem I have is that after about 20-30 minutes, the light will shut off in high power mode. It doesn't feel hot, and will immediately turn back on for a minute or two. If I put it in low power, then it will run for hours more. It seems like it's pulling too much current and something is shutting it down.
    Is this a battery issue (too much current) or a driver issue? How could I test this?

  2. #2
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    Probably battery related. Connect your voltmeter across the battery terminals while running the test. If voltage drops to zero when light goes out then you have solved the problem. Ultrafire cells are usually poor quality. Get a good battery. Over on the regular lights forum there a few threads about good packs and where to get them.
    GoPro adapters for bike lights http://www.pacifier.com/~kevinb/index.html

  3. #3
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    Pretty much the conclusion I came to.

  4. #4
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    Yeah, that screams crap batteries. That's one thing that buying cheap will fail you every time.

    Sent from my XT1565 using Tapatalk

  5. #5
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    In my experience, if the driver is some cheap chinese one it may be overheating if you have only one LED and the 7.4V (nominal) battery.

    Is the driver heatsinked, preferably to the lamp body?

  6. #6
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    Diver isn't heatsinked, as there's nowhere really to sink it to. Any recommendations on different drivers?
    I was wondering if the protection circuitry on the battery may be an issue. So many variables. I really should just DMM the crap out of the assembly and see what happens.
    My third light (with a better battery) doesn't crap out in the same way.
    Buying cells in Canada is a nightmare, since it's illegal to air freight any cells, so local cells are about $17CAD each (about USD$12.60), which is pricey.

    I'm running my packs in a 2s2p configuration. Will there be any benefit to running 4s if it is a battery issue? I don't see how there would be, but it's worth an ask.

  7. #7
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    No especially with single emitter. Actually cause the driver to run a bit hotter.

    If you think about the cost of cells as that quality cells will last for years, what is $50 for a good battery pack. Then your done, problem solved and pack will likely out last most cheap lights.

    Sent from my XT1565 using Tapatalk

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