Author Topic: LED power consumption confusion.  (Read 3716 times)

fignewton83

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LED power consumption confusion.
« on: January 11, 2016, 06:15:08 AM »
I'm using a killawatt type device to measure the watts used from some led fixtures. I'm getting some results I don't quite understand. Please shed some light on this.

My setup is as follows: Outlet(approx. 217v)--->Meter--->Powerstrip(3 outlet)--->LED light #1
                                                                                                                 |
                                                                                                                 --->LED light #2

LED light # 1: 50 watts consumed @ .395a
LED light # 2: 51 watts consumed @ .278a
#1 and #2: 43 watts consumed @ .590a ?????

Basically my meter is telling me I'm consuming less electricity with 2 lights than a single light? I'm pretty sure this has to do with parallel circuits and ohms law or maybe power factor but I would like to understand this thing fully.

I checked around the house with similar 2 light fixture setups and I see the same kind of results. Even with florescent lights.

Can somebody explain what I'm seeing?

SeanB

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Re: LED power consumption confusion.
« Reply #1 on: January 11, 2016, 11:29:18 AM »
Probably both an artefact of having 2 different LED lamp types and a meter that has issues reading high harmonic currents. The lamps likely are using half wave rectification, as 1 diode is of course cheaper ( by around 5c) than 4, so what you are getting is the one lamp is drawing on the one half of the sine wave and the other on the unused other half. The meter likely is misreading this current draw, leading to the erroneous figures. Try turning the one lamp around ( if it is in a bayonet or GU10 type style) and see if the current draw, and total draw, is different. A picture would be nice as well of the setup.