Faulty power supplies?

Nicklas · Mon Mar 23, 2020 10:29 am

Hi all

I've outfitted a rack with 16x Bridgelux eb series gen2 10 inch 5000K 19.5 V LED strips, as well as a Meanwell HLG-185H-20A power supply, connected in parallel. The lights do turn on, however, the supply only pulls 47 W from the wall (should be in the order of 100-200 W), and does not react to the potentiometer screw that is supposed to vary the current between 4.6 and 9.3 A. The voltage adjusting screw works fine.

I wrote the seller, and he refunded me right away. So I thought it was just a faulty unit, and I ordered 2x Meanwell HLG-240H-20A supplies, as I decided I wanted some more power, and I also wanted to build another rack.

So it turns out that these 2 new power supplies do the exact same thing, except they pull 54 W instead of 47. Have I just been extremely unlucky, or am I missing something that I'm doing wrong?

What would be my best bet? Should I sent the two units for RMA and ask for the same type of units, or should I ask for another model number? Or maybe an entirely different brand?

If I got the HLG-185H-20 model instead, which has the voltage and current fixed, would the strips accept 20V or does it have to be 19.5V?

Thanks

Mon Mar 23, 2020 10:46 am

Do all the strips light up?
Seems like something is wrong with your voltage.
Check you have your voltage on full first.
Maybe show some pictures of how you have it wired up

Nicklas · Mon Mar 23, 2020 11:37 am

All the strips light up.

I measured the voltage to 19.5 V.

I have wired them in the simplest way possible for parallel - the positive terminal from the driver to the first positive terminal on the first strip, the 2nd positive terminal on the first strip to the first positive terminal on the second strip, etc., and vice versa for the negatives.

I can take some pictures later.

Nicklas · Tue Mar 24, 2020 10:29 am

The voltage measured directly at the driver output is 19.5 V, while it has fallen to 18.3 V on the last strip.

end_of_the_tunnel · Tue Mar 24, 2020 1:41 pm

Have you tried wiring them individually, all parallel to the driver? Instead of daisy-chaining.

Tue Mar 24, 2020 8:33 pm

You are getting voltage drop, that still doesnt explain why they are not powered up correctly. Each strip needs its own connection to the driver. Try that first and see what happens

Nicklas · Tue Mar 31, 2020 8:28 am

Well, I should have read the entire data sheet instead of only the first couple of pages. The current follows the voltage in a way that looks exponential between approx. 18-22V, so I just had to increase the voltage a bit more, and the current started to increase a lot. Now, since I had daisy chained the strips, they received a very different voltage, and because of the exponential increase in current, I will have to re-wire it all so that there is an equal wire distance to the driver from every strip.

Tue Mar 31, 2020 9:47 am

My first answer was for you to check if your voltage was on full. Did you not do that?

Nicklas · Thu Apr 02, 2020 9:17 am

I did check the voltage immediately after it exits the driver, and it was at 19.5 V, which I assumed to be fine, since the forward voltage for the strips is listed at 19.5 V.

I did not realize that small increases in voltage was supposed to be used to hit the correct current, I thought the current was simply determined by dividing the total amperage of the driver by the number of LED strips.