Luxeon V with abnormal high voltage

Zelda · 2018-03-18T15:29:38.000Z

Recently I ordered a Luxeon V mounted on DTP from led4power.

I measured the current draw with a power supply, the wire to the DTP board are AWG20.

@3.4V I only get 2.8A, at 4.2V its 6A.

According to https://budgetlightforum.com/t/-/47339/73 I should get the 6A @ 3.4V.

What could be wrong/faulty?

EasyB · 2018-03-18T15:35:33.000Z

There can be large voltage drops between the power supply meter and the leads. Have you verified the voltage by measuring closer to the LED?

Zelda · 2018-03-18T16:16:46.000Z

@EasyB: Thanks for the advice! The voltage meter from the power supply is totaly out of scope...

I soldered directly thick wires to the 20AWG wires and took short (25cm) 4mm 2.5mm2 (AWG14) cables, stronger clamps and measured the voltage with a DMM:

Now I get @3.4v 4A, @3.7v 6A.

Does this new luxeon V need a "burn in time" like the old Luminus SST50/SST90 to drop the needed voltage?

EasyB · 2018-03-18T16:39:27.000Z

I can’t quite picture exactly your measurement set-up, but I might suspect you still have voltage drops you are not accounting for, like at the clamps. It doesn’t take a lot of resistance to drop 0.3V at 6A.

Zelda · 2018-03-18T20:31:35.000Z

New setup: Now I get @3.6V 6.18A:

Thats a little closer to de goal of 3.4V@6A.