First bulb
I bought 5 of these at $6 each a few months ago and have been using them diligently, i borrowed a kill a watt today and tried two of them and both read at 8W, with a PF that fluctuates between 0.94 and 0.97
How many watts is it actually using (am i being billed for), the packaging says 12W even though the link says 11W and does the power factor influence what i am billed for?
Second bulb
I then got 5 of these for $1.25 each after coupons and tested two of them, they say 10.5W on the package but use 7W according to the kill a watt, and the power factor fluctuates between 0.79 and 1.0
I was also using the kill a watt for measuring LEDs. But it turns out it isn’t accurate for devices that have low load and low power factors.
You would be be billed for 11W, but because of the low power factor (0.63) the generator will need to generate 17W. So you aren’t saving the planet as much as you thought.
Strange that Philips made it so low however. Energy Star standards in the US required PF > 0.7 for lamps above 5W. Apparently this standard only comes into force later this year however. The California requirements, “CA Quality LED Lamp Spec”, require a PF > 0.9.
Could be low sampling rate, or high frequency interference from active power correction chips. I switched to using the Cabac CCI Powermate power meter (sample rate 4800 / sec) and got much more sensible results. The device is also about 10 times the price however.
