We have a folding camper (halfway between a trailer tent and a caravan) with an interior light that used two 8W fluorescents. Obviously, the only thing to do was to strip these out and replace with a more pleasant and less power-hungry LED.
The final result:
Some notes:
I'm very pleased with the final result: the LED is nice and bright, a good match for the old tubes even through the diffuser, with a pleasant colour (it's a warm white unit) despite the poor-spec CRI. On its own, it should run for over a week non-stop from the 110Ah leisure battery...
The final result:
Some notes:
- the LED I used was sold on eBay as a "10W 1000 lumen" unit with a Vf of "11–14V", for just £1.89 posted from Hong Kong. I did some research: from the spec sheet it's actually a "6.7W" unit intended to be driven with 560mA, no built-in resistors. That same spec sheet claims 1890–2430 lumens, a truly spectacular efficiency. What do you mean, of course it's true :ironic:
- it was actually a poor choice, as the camper's 12V supply could realistically be anywhere from 12V to 14V. The LED couldn't be driven directly from this, a simple series resistor wouldn't suit, and it'd take an unusual regulator to be able to cope
- so I used an unusual regulator: a Mean Well LDB-500LW (PDF) buck/boost regulator that'll take 9–30V in and provide 500mA at 2–32V out, with no restrictions on input versus output voltage. This slightly under-drives the LED, which'll be good for lifetime and heat. Turns out a 500mA drive current requires a whisker under 11V as you'd expect from the specs.
- I actually bought five of these regulators as the postage for a single one is horrific. I plan to recoup some of this via selling the remainder on eBay.
- The LED is heatsinked (heatsunk?) via a 3mm aluminium plate, cut to the maximum size that comfortably fits in the lamp unit. The LED is firmly bolted on with a super-thin smear of thermal compound between. The rear face of the plate is thinly sprayed to increase emissivity, and the plate is mounted with a gap behind it to allow some convection. In testing, this gets only warm, which bodes well for lifetime.
I'm very pleased with the final result: the LED is nice and bright, a good match for the old tubes even through the diffuser, with a pleasant colour (it's a warm white unit) despite the poor-spec CRI. On its own, it should run for over a week non-stop from the 110Ah leisure battery...
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