LED lights

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LED lights

Post by Sam Spoons »

I have LED lights in the studio, to save running 230VAC to each unit I bought a LED driver. The problem is that the first driver died, probably due to my using a constant voltage driver to drive LED lamps that are designed to be driven by a constant current driver. I believe this means that the lamps don't have a resistor in series case of any diodes failing (presumably to protect the driver/wiring from a short circuit).

That's as much as I know about it and while I have a replacement driver I have yet to fit it as I don't want to risk the same issue causing it's untimely demise. Does anybody understand these things and can maybe advise if it's possible to wire a resistor into the circuit for each lamp to prevent the problem, or am I barking up an entirely different tree?

The new driver (for powering 4 lamps) :-

Image

The original driver that comes with each lamp :-

Image
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Re: LED lights

Post by Folderol »

From the look of it, that one seems to be constant voltage. The clue is it says 38V +-5% but gives no tolerance figure on the current, whereas the 'proper' one has it the other way round.
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Re: LED lights

Post by James Perrett »

What lamps are you driving - there are various different types.
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Re: LED lights

Post by Sam Spoons »

They are these (though differently branded). https://www.amazon.co.uk/Surface-Mounte ... 76&sr=8-34
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Re: LED lights

Post by James Perrett »

I would suggest you use them as intended and power them from a separate driver for each fitting. You need to use the matching driver for the fitting (as in the second picture) - not the one in the first picture.
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Re: LED lights

Post by Sam Spoons »

That is a last resort as the lamps are currently wired for DC low voltage, rewiring with mains cable is doable but I'm trying to avoid that option as it's quite a big job.
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Re: LED lights

Post by James Perrett »

If you want to avoid running new cables, I think you will either need to open up the fittings and draw out a circuit diagram of what is in there so that you can choose the appropriate power supply for the whole system, or you will need to replace the fittings with constant voltage types.
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Re: LED lights

Post by Sam Spoons »

Thanks James, the fittings are very simple AFAICS, series wired strips of LEDs with no visible resistors. I've had a rethink and I believe I can rewire using cat5 cable to supply four separate supplies from four constant current drivers, that would require no more than 300mA per pair which I think should be fine (will do the sums properly before committing). I'd still prefer to use the far more substantial 90W driver if I can work out a way to do it as the wiring is already in place. It worked well for 6 months before failing and I'm still not sure the failure was due to a mismatch or something else. The (constant) voltage was below the rated voltage of the lamps/drivers so failure of one or more LEDs in a unit may have led to a higher voltage causing the failure of the big driver or it might simply have been a faulty unit.
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