Saturday, 27 February 2016

220V LED light strips / rope lights

Feeling in need for a bit more light under the kitchen cabinets, I bought 1m of LED lights from ebay.  Where else?  It was worth the 10p, unlike the 0.5m 'power cord' which was a further £10 and I'd need to cut the plug off and extend the wires.
The spec was the usual vagueness for 'quality' products and is 60 led/m (5050 leds) IP66 - waterproof!.  Digging around a bit (there was a RoHS cert to con you into thinking it was CE marked, lol) the manufacturers site stated 12W/m
There was a bump in the cable and I was suspicious that this did something. A look at the rope showed that the LEDs  are not wired to take AC, so I identified the +ve terminal and put ~50VAC through a full wave rectifier 49VDC (8A one from the scrap box, but 0.5A is fine assuming it's rated for mains). This caused the LEDs to glow. Putting a full 240VAC gave a good brightness. Power consumption is around 10W.
DC volts measured 221V, DC current 27mA, which works out at 6W.  Why the disparity?  Probably the fact that the DC is not smoothed, so the meters are averaging a bit. The peak voltage would be around 240 x 1.4, so say 330VDC.
You have to get the correct polarity, but is shouldn't harm if it's the wrong way around.

I've read that these no-name and often found strips will lose about 1/4 of their initial brightness if run continuously for 2 months or 1440 hours, or a year at 4 hours per day. This is because the LEDs are no-name items, maybe even floor sweepings, or simply driven too hard. Part of the problem is the materials used which go opaque. If you want a nice system to light your house you'll need to dig deep and look for the likes of Philips etc.

If you've found this blog post and think you could also save £10, you need to understand what the technical terms are. Don't post a question asking me to explain, 'cause I won't. Darwin rules.



And the finished article fitting nicely into a surface mounted switch. A 0.8A fuse was chosen as I have a surplus. The connections are mad by pushing 1mm tinned wire 10mm into the rope.
In use, the brightness is a long way from a 12W fitting. Maybe 6W is closer.


No comments:

Post a Comment