BLF A6 XPL 1600LM: Turbo mode damages Led?

Flashlight Modding and DIY Parts
1

Hello

I am wondering about the led driver in BLF A6 for Cree XPL. This is a direct fet driver with one linear driver-ic for moon light efficency.

In turbo mode the driver uses only a simple direct fet with 100% pwm.
So there shall be an current of about 5.65A: Deconstructing a flashlight | Deepak Kandepet (this is about another led and similar flashlight, but the fet principe is still the same: directly connect the led to liion battery)

But the XPL is limited to 3A with 3.35V or similar?

And a full charged liion battery has 4.2V, maybe little unter 4.0V or so after some very short time.
And if the battery can deliver more than 3A, maybe 5A or 8A, than the led would be damaged in some time and decreases light output power?

Is this still ok for the led?

2

Yes, the XPL should be fine being driven directly by a FET.
The BLF A6 is a very popular flashlight and has been trouble-free.

The chances of burning your hand due to the head's blazing heat is way greater than getting the emitter damaged so be careful


3

The A6 cannot maintain max output for very long. It only stays on turbo for what, 40-45 seconds, maybe? Enough time to get quite warm, but probably not enough time to cause any serious damage, other than internal timer for reverse clicks (half-press, medium tap) getting screwed up by the warmed up driver.

Realistically, I think you’re not going to be able to pull more than about 4.5A of current on an un-modded A6.

4

Those “max” ratings on spec sheets are full long-term use while maintaining the full efficiency and lifespan of the emitter, and not on DTP (direct thermal path) board IIRC. The X-PL HD can easily withstand WAY more than 3A as long as the thermal path is good.

5

XP-L V5 Output & Death test by Texas_Ace Surprisingly close to the XP-L2 at low currents but not nearly as rugged.

XP-L HI 1A V2 LED Output test by Texas_Ace, Well, you have seen the HD, this is the HI. It is exactly what you expect.

If you do care much with respect to the maximum current which reachs your flashlight emitter, you can swap the driver with some sort of regulated driver (some of the newer Convoy MOSFET linear drivers, for example). Other than this, you'll be fine.

6

I’ve had a few of these, for quite a while, with bypassed springs even, and there hasn’t been any damage to the emitters. They have been great lights.

7

The nice thing about emitters with a high Vf (like the X-PL) is that there is little worry about frying the LED on direct drive. Unless we have batteries with higher voltages sometime soon which wouldn’t surprise me, 4.35v li-ions are already out there.

Now if you had a single Nichia 219B in that light, then you should worry! That little guy is HUNGRY for current.