I had a bunch of Seoul p4's in series and they went. Now I have some Cree XR-E's that are toast. I don't get it. I am using a microdrive9 350 mA driver and have the voltage correct ( I checked everytime). Each time I connect the leads from the driver to the star it flashes and then is dead IF I connect them to the star on the same side. I mean if you look at the star and there is pos on one half and neg on the other with 2 contact points each, choose the two contacts closest to eachother and connect. It seems that if I choose the two contacts that are furthest apart I don't have the problem. Then again, I modded my Zenix IQ and they are the closer set, with no problem. Why do I keep losing emitters? i can't afford this and DX will not keep sending replacements. HELP!!!
Why does this keep happening?
- Thread starter mitaccio
- Start date
Help Support Candle Power Flashlight Forum
LukeA
Flashlight Enthusiast
In this case it's line voltage rather than battery.
would that make a difference then ?
LukeA
Flashlight Enthusiast
No, not really.
georges80
Flashlight Enthusiast
FYI:
The explanation of what is happening is that without a load connected to the driver, the driver output voltage will rise to whatever the open circuit limit is. This depends on the type/style of driver, but typically the voltage will be much higher than the LED rated voltage.
This means that the output capacitors are now charged to this same higher voltage. Now you connect the LED and for the instant that it takes for the capacitors to discharge and the driver to go into current regulation you have a large current spike going through the LED. How the LED handles that current spike is dependent on the LED construction, bond wires etc etc.
Typically you will either blow the LED or at the very least damage it. I've seen Luxeons damaged so that they still work at higher currents, but at low currents they don't "start up", i.e. they seem to require a certain voltage/current before turning on. I've also seen Luxeons just die outright.
Anyhow, with a current driver you really need to have a load connected BEFORE applying power to the input side.
cheers,
george.
The explanation of what is happening is that without a load connected to the driver, the driver output voltage will rise to whatever the open circuit limit is. This depends on the type/style of driver, but typically the voltage will be much higher than the LED rated voltage.
This means that the output capacitors are now charged to this same higher voltage. Now you connect the LED and for the instant that it takes for the capacitors to discharge and the driver to go into current regulation you have a large current spike going through the LED. How the LED handles that current spike is dependent on the LED construction, bond wires etc etc.
Typically you will either blow the LED or at the very least damage it. I've seen Luxeons damaged so that they still work at higher currents, but at low currents they don't "start up", i.e. they seem to require a certain voltage/current before turning on. I've also seen Luxeons just die outright.
Anyhow, with a current driver you really need to have a load connected BEFORE applying power to the input side.
cheers,
george.
