Here is my setup

1 Circuit containing 7 X 5W COB (chip-on-board) Recessed light

Power supply -24V @6A rating

I removed the individual power supply that comes with led light. I measured the output of the transformer it was 23.6VDC....

Now the problem is I have all the lights on but they all are different brightness. The wiring is done in parallel. I am using 12GA AWG

1st- Extremely dim
2nd- Brighter
3rd- Brightest
4th- Dim
5th- Dim
6th- Dim
7th- Bright 

Any ideas why this would happen?

Circuit starts from left in following photo:

Another angle

1 Answer 1


Look at the label on the 'power supply' which came with each of those LEDs.
There's a reason its's called an "LED Driver" and not a "Power Supply".
That box supplies a constant Current to the LED, not a constant Voltage because LED brightness depends on Current, not Voltage.
LEDs are 'non-ohmic' devices which means they don't follow a linear voltage/current relationship like an old incandescent light bulb.

Measuring the output voltage of one of these drivers with no LED connected will only tell you what the maximum voltage is that it can provide with no load - not what it will provide when it's actually driving an LED at its rated current.
Measuring the voltage with an LED connected will tell you what the characteristics of that one particular LED are and should not be extrapolated to other LEDs.

By applying a constant voltage to your LEDs and not controlling or limiting the current (other than the 6A overall limit of your new power supply), it's entirely possible that you've already damaged some or all of them.

Remove your 24V 6A power supply, put the original LED Drivers back on, and hope the LEDs still work ...

The only reliable way to run these LEDs off a single LED Driver is to connect them all in series (not parallel) so that they all have the same current flowing through them (and therefore the same brightness).
The single LED Driver will need to be able to supply a voltage of at least 7 x each LED's nominal voltage (because the voltages add up when they're in series).

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