Fenix PD20 Driver Confusion: Is it really a CR123A light?

I received my Fenix PD20 from the Wallbuys Instant Kill sale today. That was quick! (ordered 5/19, eight days from order to mailbox)

This is a nice light:

  • Great ano
  • Square threads, buttery smooth
  • Nice matching clip
  • Good OP reflector
  • XP-G R5 puts out decent light, although slightly green tint
  • Tailstands, but a little wobbly, clip sticks out just past the end

Anyway, now that I have it, I'm confused about the driver.

I pop in a Li-Ion 16340 and:

  • With the head tightened I can switch between is Turbo (quite bright) and Strobe (This much is correct).
  • With the head loosened I can switch between Turbo, Turbo, Turbo, and SOS.


OK, get a half-dead CR123A, pop it in and... all modes are fine.

  • With the head tightened I can switch between is Turbo (quite bright) and Strobe.
  • With the head loosened I can switch between Low, Med, High, and SOS.

The CR123A was down to 2.8V.

Time for Mr. Supply, first name Power.

This driver loses mode control above 3.3V (starting to look like a boost driver without PWM mode control).

To top it off, it runs just fine down to 1.5V, even bright on Turbo mode (draws over 2A).

So, is this driver a 1-2 NiMH driver or a CR123A driver?

If I could get the darn head apart, I'd 'correct' the problem with a QLite driver and update to XP-G2. I'm pretty sure the head is glued together (another Fenix special touch). |(

Yes....you loose med and low initially on a 16340 , as light runs in direct drive from max output until it hits the low mode output level. At that point, it then switches into regulation - but only briefly, as the battery is typically almost exhausted by then.Those Instant Kill's can turn out to be a disappointment if you haven't done your homework first.

On a primary it's a nice light, however.

That is pretty much what I am observing, thanks.
Agreed on the homework thing. I basically assumed it would be fine on a Li-Ion 16340. I’ll get some LiFePO4 cells which should help a little.
I also forgot that the CEO of Fenix must hold a lot of stock in LocTite Inc. :expressionless: