I think I have a never used 17mm version in the 3 amp type that I don’t need. But I have not unpacked a bunch of workshop offs ‘n’ ends yet so can’t even verify for a bit. It might even be a 6 amp; my memory fails me.
I’m been fooling around with a light I built with a 3A LD-A4 driver and a Luxeon V with the NTC on the MCPCB.
It’s an 18350 so I figured direct drive won’t pull enough amps to damage the emitter.
The thing is the light gets hot enough to do the 15 blinks and shut off. I have the third wire connected to the temp sensor pad on the MCPCB, so I thought the light would step down in brightness before the complete shutdown occurred.
After that I put it back in CC mode and the same thing occurs but it takes a while longer. No stepdowns in brightness, it just runs until it does the 15 blink thing and turns off.
I have checked continuity from the T pad on the driver to the pad on the MCPCB and to the NTC itself and the connection seems fine. Does the type of wire matter? I’m using some scrap wire because it’s the thinnest I have.
From the Manual:
“…D-x4 has two OTP protections: internal and external. Internal OTP uses microcontroller internal temp. sensor which monitors driver’s PCB temperature; if PCB temperature becomes higher than predefined threshold (~105°C), light will blink fast 15 times and driver will shut down completely to prevent circuit damage. Role of internal OTP is to protect driver from fault conditions, such as too high power dissipation caused by improper choice of LEDs/batteries combination, or not good enough thermal path. …”
HTH
To add, Luxeon V has pretty low forward voltage if I remember so driver itself will have to burn off that excess as heat. So make sure driver is making solid contact with heat path where possible. Internal OTP may be kicking in first.
Might be worth checking, since it’s 18350, it’s possible voltage sags enough to do LVP which has a 10 blink shutoff which may look similar.
I have stuffed driver cavity with thermally conductive “pillows” when using LD-A4 drivers. That prevents the driver overheating. Kaidomain sells them, probably others too.
Yeah.I understand the 15 blinks/shutdown is the internal OTP. But the external OTP, which is the NTC on the MCPCB has a lower threshhold and should cause the driver to lower the brightness at 65c. That doesn’t seem to be happening.
The external NTC probably isn’t hitting 65c, it sounds like the driver is hitting 105c before that happens and unless you have amazing hands you will let go of the host before 65c.
Did you get the V from L4p? I have a 5700K Luxeon V i bought from L4P and it is one of my favourite LEDs.
Yea I got the 4000k ones. I like the LEDs, the drivers seem kind of needy. I think Convoy 5A drivers would be a good match for this emitter as well. I might do that.