Having noticed major discrepancies between the advertised power ratings and the real power ratings of some hydroponic GU10 lamps (grow lamps) I decided to test a range of LED GU10 lamps I had. The results are as follows:-
3W RED 1.9W
3W YELLOW 2.8W
3W GREEN 2.6W
3W BLUE 2.9W
3W COLD WHITE 3.2W
3W ULTRAVIOLET 4.1W
4W WARM WHITE 4.1W
3W RGB 1.6 TO 1.8W
3W RGB 1-3W (1W PER LED)
4W WARM WHITE 4.2W (Duracell branded)
2W WARM WHITE 2W (PHILIPS)
6W HYDROPONIC 2W!
6W HYDROPONIC 3W
5W HYDROPONIC 1.9W (6 CHIP)
Most of the three watt lamps are probably based around the BP3102 3W lamp driver chip which explains the variation between the coloured lamps since a standard circuit driving the LEDs at about 350mA will result in a power dissipation dependent on the combined forward voltage of the LEDs. Hence why the red lamp only drew 1.9W.
The hydroponic lamps (grow lamps that use a mixture of red and blue LEDs) are clearly involved in a bogus rating war on ebay as they were between half to a third of the advertised power and are probably just using 3W drivers.
The Philips lamp is the only one that used a capacitive dropper with two different capacitor values in parallel to give a very accurate 2W rating.
3W RED 1.9W
3W YELLOW 2.8W
3W GREEN 2.6W
3W BLUE 2.9W
3W COLD WHITE 3.2W
3W ULTRAVIOLET 4.1W
4W WARM WHITE 4.1W
3W RGB 1.6 TO 1.8W
3W RGB 1-3W (1W PER LED)
4W WARM WHITE 4.2W (Duracell branded)
2W WARM WHITE 2W (PHILIPS)
6W HYDROPONIC 2W!
6W HYDROPONIC 3W
5W HYDROPONIC 1.9W (6 CHIP)
Most of the three watt lamps are probably based around the BP3102 3W lamp driver chip which explains the variation between the coloured lamps since a standard circuit driving the LEDs at about 350mA will result in a power dissipation dependent on the combined forward voltage of the LEDs. Hence why the red lamp only drew 1.9W.
The hydroponic lamps (grow lamps that use a mixture of red and blue LEDs) are clearly involved in a bogus rating war on ebay as they were between half to a third of the advertised power and are probably just using 3W drivers.
The Philips lamp is the only one that used a capacitive dropper with two different capacitor values in parallel to give a very accurate 2W rating.
I wish I'd seen this earlier. I recently got bamboozled by getting some cheap "Chinese 8W" grow lights that are much dimmer than the real 5W lamps I had previously in my hydroponics.
I was honestly expecting a lot worse than that. Aside from those hydroponics lamps, most of those are at least semi-accurate (or based on the driver chip being used, in the case of the red LEDs). Maybe the ratings start to get a bit more hand-wavey when you get up to higher power. I guess it isn't like knockoff lithium cell capacities, where the manufacturers just put down whatever number they feel like.
Have you been able to test out the grow lamps at all to see if they actually work to grow plants? I imagine the lower wattage would result in problems with distance from the plant to the light, but also if it's the wrong wavelength they may not grow correctly.
How much did the hydroponics lamps cost?
If I wanted to say make my own 660nm red lights could I buy those circuit boards featured in recent videos and purchase the right leds?