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I have LED Driver
Model: LD-361500-105MPF Input: 90-260VAC 50/60Hz and Output: 20-36VDC, 1500mA+/-5%.

I connected it to the LED COB Citizen 1212C4 which needs, according to datasheet (COB's datasheet link, page 6), 37V at 1500mA.

When i power up this circuit i get power consumption of 60W, im guessing 36V and 1.66A. its about 11% of a difference and not 5% that is declared on the driver. I'm cooling it easy with active cooler, temps dont go crazy high (around 30°C?).

My question is can this be ran for a long time without any problems?

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  • \$\begingroup\$ Sounds like a measurement error. Does this include 11% losses? \$\endgroup\$ Mar 18, 2017 at 16:11
  • \$\begingroup\$ I answered about the LED, but now I'm wondering if you were asking about the driver or the LED. The LED should be fine, but I can't find enough info on the driver to comment about that. What do you mean you are 'guessing' about the output measurements? \$\endgroup\$
    – AngeloQ
    Mar 18, 2017 at 16:12
  • \$\begingroup\$ well, if i connect this driver to a chinese 50w led COB that is rated for 32-36V it is ok ( wattmeter shows 50w of a power consumption), but if i connect it to that COB it shows 60W of a power consumption. I have also tried it with a Cree CXA2530 and it goes to a 65W of a power consumption. Im "guessing" couse i did not measure the voltage and amperage in the circuit but the P(W) is accurate. cree.com/led-components/media/documents/XLampCXA2530.pdf CXA2530 shows that this LED needs almost 40V at 1500mA. \$\endgroup\$
    – Josip7171
    Mar 18, 2017 at 22:25

1 Answer 1

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Yes it can be run for a long time as long as the temperature of the LED stays within operating temperature. A CoB drawing 1.5 Amp needs to have serious thermal management.

If the LED gets so hot it will burn you instantly or if water sizzles on it, it is too hot. Keep its temperature below 100°C.

At minimum you will need a heatsink and very likely a fan. IF no fan the heatsink is going to have to be big.

This CoB can take 2.7 Amp so you are in good shape that way.

This supply has 88% efficiency.

36v x 1.5A = 54 Watts

54W / 0.88 = 61.63 Watts. Near Perfect, Running exactly as expected.

It should be the job of the power supply to limit the power to 50 Watts if necessary. You are driving the supply 20% over its rated capacity.

I would be concerned if the power supply gets too warm. It should not get too hot to hold in your hand.

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  • \$\begingroup\$ Ok, so what you are saying is that i need to watch out for the LED driver's temperature and the LED will be ok if it have a good thermal management? What bothers me is that this driver gives out 50W of power if it is connected to a LED chip with 36V rated voltage. I believe that this power "boost" comes from a fact that a COB needs more voltage than this driver can provide so some kind of imbalance comes into play. If i connect this same driver to a CXA2530 that requires 40V at 1500mA, this "boost" goes even more up! amperemeter shows 1.93A value being drawn by that LED COB. \$\endgroup\$
    – Josip7171
    Mar 19, 2017 at 9:57
  • \$\begingroup\$ i had one driver like this. went belly up after few days. \$\endgroup\$
    – IceCold
    May 4, 2017 at 21:01

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