LED bulb question

[Mr V]

Originally Posted by Ether

Two different LED bulb models by the same manufacturer. Packaging says:

bulb1: 800 lumens, 2700K, 150 mA @ 120V, 8.5 watts

bulb2: 800 lumens, 2700K, 120 mA @ 120V, 10 watts

Can someone explain what's going on here?

Interesting my first thought was different efficiency emitters for the different models could account for the same light output with different consumption. but the math on the wattage doesn't add up.

The other question is one a dimmable and the other not?

I had an interesting experience recently when I installed a non-dimmable LED bulb in a fixture that was connected to a lighted switch. Turned on the switch and everything worked fine. Then I turned off the switch and periodically the bulb would flash on for a very short period. Scratching my head and then looking at the lighted switch the light in the switch would flicker corresponding to the bulb flashing. I later put a dimmable bulb in that fixture and the flashing stopped.

In retrospect I concluded that the slight voltage leak through the switch's illumination allowed the capacitor in the non-dimmable bulb to charge to the point where current would flow through the LED. It would then drain the capacitor, the light would go off, the capacitor charge again and the cycle repeat.

So a dimmable bulb would have higher consumption at the same light output due to the added control circuitry's power consumption. But that of course does not explain why the math doesn't calculate out.

[Ether]

Originally Posted by Mr V

...is one a dimmable and the other not?

I was wondering about that.

Bulb2 is dimmable; bulb1 is not.

Originally Posted by Richard Wallace

It would be worthwhile to test these two bulbs using an inexpensive meter such at the Kil-A-Watt

Interesting you should mention that. It's on my list of useful tools I should look into. Do you have one of that model?

[Richard Wallace]

Originally Posted by Ether

Interesting you should mention that. It's on my list of useful tools I should look into. Do you have one of that model?

Yes, and you are welcome to borrow it. PM to arrange a meeting time.

I happened to have two Cree LED bulbs marked 2700K 800 Lumens 9.5W 120V 60 Hz 79 mA on hand. From my household 120V, both draw about 8 Watt, 70 mA, and both measure PF = 0.88 using my Kil-A-Watt.

Their markings indicate ~unity power factor: 9.5W / (120V x 79mA). Small print also says they are UL Listed and suitable for damp locations. Another marking 2213 suggests they were manufactured in Week 22 (late May/early June) of 2013.

What brand are your LED bulbs?

[Ether]

Originally Posted by Richard Wallace

What brand are your LED bulbs?

Walmart "Great Value".

They were selling them for 82 cents a piece so I picked up a dozen.