Mixed emitters in parallel

Hi all,

I was bored today so I decided to try building a micro mag with mixed emitter brands and versions. Specifically, I re-flowed a Nichia 219b 92CRI, an XP-G R5 cool white (6500k or so), and an XP-G2 R5 3C onto an aluminum triple parallel MCPCB from Kaidomain. The idea was to see what would happen to the emitters and how the beam tint would look. Just to be mean to the emitters I installed one of Wight's single sided FET drivers.

Testing of the light engine during the build led me to believe the combo was going to be a bright one. Sure enough, once installed the light drew more than 6 amps out of an e-fest IMR 14500. For a short while. The emitters survived even a 2 minute sprint on turbo with no observable ill effect. The head of the light was too hot to touch. Not surprisingly, the beam tint is a rather pleasing neutral white.

The point of this thread is to ask the hive if there is likely to be any future consequences to running three emitters of slightly different forward voltages in parallel at around 2 amps each. The other thing that puzzles me is that this light is running a full amp higher than any other triple micro I have built. The Nichia 219b triple micro mags max a 5 amps and my hottest XP-G2 triple micro mag got to 5.3 amps. I saw 6.3 amps at start up on this light. Theories, supposition, and hard science are all welcome.

Brian

I’ve seen multi emitter in 2S2P setup but never in 3P… good to know it works well!

By the way I would swap the mcpcb for DTP copper since you’re running 2A per led.

In a parallel circuit, the voltage across the loads will be the same while the current through each load can be different. In a series circuit, the current across the loads will be the same and the voltage across each load can be different.

I would measure the forward voltage across the parallel loads. Then I would consult the forward current versus forward voltage curve in each LED’s datasheet. That should give an indication of the current going through each LED. Add these calculated currents together and see how well they match with the measured current from the driver.