Cooktop LED's for overhead microwave

[hydro_pyro]

Problem: The light under the microwave is not bright enough. I can't see my food while I'm cooking. There's one 30 watt light E17 intermediate-size screw-base bulb in the underside of the microwave. Unfortunately, there isn't a brighter alternative or commercially-made LED retrofit. So, I made my own.


Before:

After:

The light: Cree XML2 single-die "warm white" LED's, JB epoxied to an aluminum heatsink, powered by a constant-current driver circuit, and adapted to the E17 socket using a customized bulb base with a plastic grip-wing epoxied into it.

I built this single-LED unit for my sister's kitchen:

These LED units are about 3X as bright as the factory light bulb, but consume 85% less electricity. WIN.

 

[blah9]

Great work! Thank you for sharing. That looks like a really nice upgrade.

 

[mds82]

I've retrofitted all my undercabinet lighting as well. What did you use for a driver?

 

[markr6]

NICE! My microwave looks similar. My wife (and I) complain about it at least once a week becuase it's soooo dim!

 

[hydro_pyro]

I've built several of these for family and friends, using various constant-current driver circuits obtained from overseas sellers on eBay.

The LED chips are Cree XPG2 warm white.

 

[hydro_pyro]

I built myself a new light. This one has a separate driver for each LED.

I hooked up a diode bridge and series ammeter. .035A, or 4.2 watts. I guess the 3W drivers are actually closer to 2W.
I slipped a meat thermometer between the heatsink and drivers... 131°F after 2 hours ON. I hope they stay under 200° with the stove in use. We shall see.

Here's a new before and after, taken with camera exposure locked for comparison.
First, version 1... Two LED's in parallel powered with a single driver...

...and version 2, with two drivers, one for each LED:

This is stupidly bright now.

 

[Luciaro]

Next step is a dimmer ;-)

 

[hank]

Nice, thank you! To get a kitchen remodel permit, we have to have one "dedicated LED fixture" and this looks like the answer.

The architect may hate it (grin); she was going to specify in-ceiling LED downlight fixtures, which require fireproof attic insulation and air-sealing -- sounds like a formula for overheating.

> I guess the 3W drivers are actually closer to 2W.

Argh. Can you specify a LED and driver you know work together properly, for the one-star one-driver simplest setup?

I keep seeing instructions for chaining LEDs on a single driver and suspecting I'd mess that up.

 

[hydro_pyro]

These little drivers have very low output voltage, so you can't connect multiple LED's in series-- they will barely even light. I have built a couple of these with 2 LED's in parallel with one driver, and it works fine. The output is similar to using one LED, but there's better coverage with lass shadows over the cooktop.

Cree XPG2 and XTE on aluminum sink dies work well for this purpose.