Undervolting a 24V LED lighting strip

I needed better work lighting than my existing point-source light so decided to put in a 24V strip instead of the usual 12V one since there’s lower I2R losses, this is a 120 LEDs/m 2835 strip.

Since I was using it to light a workbench rather than a room I didn’t really need the full light output so I decided so see what sort of performance I’d get from undervolting. This means there’s less heat generated, so longer life for the components as well as the adhesive used to hold the strip into the alu channel it sits in.

This is the strip at 17V, although the camera does a better job of compensating for the light levels than the human eye does, looking directly at it even at this level was a bit painful.

Here’s the results, with light levels measured at 50cm because that’s how far they’ll be from the work area. Treat these as relative rather than absolute since it depends entirely on how the levels are measured.

Volts	mA	Watts	Lux
15	0	0	14
16	31	0.5	105
17	92	1.5	380
18	161	2.9	630
19	231	4.4	880
20	306	6.1	1130
21	380	8.0	1390
22	456	10.0	1630
23	534	12.3	1840
24	609	14.6	2120

2835 LED strip output vs. voltage

So it’s quite possible to run this type of 24V strip at 22 or 20V, or even from a 19V laptop power brick as long as you’re not running it somewhere where radiating switching hash into the surrounding area is going to be a problem.