Fenix LD12 continuous?

STREAMHAWAII

Newly Enlightened
Joined
Jul 9, 2017
Messages
15
Is the Fenix LD12 continuous or does it have a PWM circuit. I read that the Klarus Mi7 has a constant current and has no flicker. Trying to see my options and decide which flashlight to get. Thanks all!
 

hiuintahs

Flashlight Enthusiast
Joined
Sep 12, 2006
Messages
1,840
Location
Utah
The Fenix LD12, 2017 edition is constant current for both AA and 14500 batteries. I think I know where you are going with this question. The forward voltage drop of an LED is around 3.0v. That means if using an AA battery, the driver has to be a boost circuit. But if running a 14500 lithium ion which can have a voltage up to 4.20 volts, then the driver has to have a buck (step down) type of circuit. So the challenge to the manufacturer is to have a cost effective efficient driver that can handle all voltages from AA and 14500. Some single AA lights that can accommodate the 14500, elect to have a good efficient constant current boost type of driver for AA but when using a 14500, the driver switches to PWM. I've seen that with the Nitecore MT10A and I think the Jetbeam Jet I MK is that way too. There are probably others as that is probably the easiest way to deal with this range of voltage, without too expensive of a buck-boost driver of some type.

On a side note, if wanting to run the 14500 rather than an AA, I have found the 16340 lights to be slightly more efficient than the 14500 lights...........at least on a couple of samples that I had such as the Fenix PD25 and E15 vs the Fenix LD11 and LD12-2017 on a 14500. Since these are all lights by the same manufacturer, it tells me that it must be a little more challenging to make a driver for the AA/14500 vs the CR123A/16340. I posted that information elsewhere on CPF but for some reason I got better performance (output x time) out of the 16340 powered lights than the 14500 powered lights considering the 16340 that I used was 100mAh less.

So would I dump my AA/14500 lights in favor of the 16340 only? No. There is some advantage to having a light that can run AA batteries, because it makes it more versatile in a crises situation where you may be scrambling to find batteries. Meanwhile, I have a 14500 in both the LD11 and LD12-2017 knowing full well that I can substitute an AA if needed. :)
 
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