Specs for Cree LED used in Magicshine 900 headlight?

[SamTexas]

Does anyone know the specs for the Cree LED used in the Magicshine 900 headlight? No, not the specs for the Magicshine 900.

I'm specifically looking for the Forward Voltage and the Forward Current of the LED.

I could be wrong, but I don't believe there exists a forward voltage greater than 4.20V for LEDs. So I wonder why the Magicshine 900 uses 2s LiCo (8.40V max) instead of 1s (4.20V max). I could be wrong again, but I believe a great percentage of energy is being wasted various resistors running on 2s.

 

[texaspyro]

Almost all high power LEDs use a switch-mode driver that either up converts or down converts the battery voltage into a value that causes the desired current to flow into the LED. No power is wasted in ballast resistors.

 

[lazarus2405]

First, the MS900 uses a SSC P7 emitter, not a Cree (it's the MS1000 that uses the Cree XM-L). Its datasheets are here: http://www.seoulsemicon.com/en/product/prd/zpowerLEDp7.asp

Beyond the efficiency issue, they use switch-mode drivers to provide a (controllable) constant current to the LEDs, as they're very sensitive to tiny changes in voltage. The curve of forward current versus forward voltage is very steep. Without some kind of current limit, a small increase in the voltage could lead to thermal runaway and a dead emitter. Without a constant-current supply, you'd see huge changes in brightness as the battery voltage fell.

Some bins of the P7 can have a forward voltage up to 4.5v, though 3.5v is more typical. You need about another volt to drive the driver circuitry, so yeah, you need at least 2s to make it work.

 

[itselectric]

Does anyone know the specs for the Cree LED used in the Magicshine 900 headlight? No, not the specs for the Magicshine 900.

I'm specifically looking for the Forward Voltage and the Forward Current of the LED.

I could be wrong, but I don't believe there exists a forward voltage greater than 4.20V for LEDs. So I wonder why the Magicshine 900 uses 2s LiCo (8.40V max) instead of 1s (4.20V max). I could be wrong again, but I believe a great percentage of energy is being wasted various resistors running on 2s.

The Magicshine Cree version is rated or marketed as 1000 lumen. It used cree X-ML LED, if you want to know the spec, you should get it direct from horse's month.
http://www.cree.com/products/pdf/XLampXM-L_EZW.pdf

As the spec listed, the dc forward voltage is 6v. All LED light require some type of drivers to convert to native or require voltage. The magicshine driver is actually very good, it is based on dc-dc converter driver. However, their tail light driver is very poor. It is voltage regulator.
http://www.magicshine.com/product.asp?id=29

Ken

 

[SamTexas]

Thank you guys for the relevant and useful info. Much appreciated.