How to measure current draw on Fenixes (et al)

[EntropyQ3]

Hi.
I'm in the process of diagnosing a bunch of Fenix flashlights I've just bought.
Could someone please tell me how to measure current draw?

 

[jzmtl]

Remove tail cap, connect battery - end and battery tube with multimeter.

 

[mmmflashlights]

Take the head of the light off, put the battery on the back of the circuit, put one probe on the back of the battery and the other on the threading on the side of the head to complete the circuit.

 

[half-watt]

Hi.
I'm in the process of diagnosing a bunch of Fenix flashlights I've just bought.
Could someone please tell me how to measure current draw?

common method is to connect a DMM (with red lead in the AMP connect and not the V/Ohm connector) set on the appropriate DC current position b/t the negative end of the last cell inside of the Fenix tube/body/barrel and the tailcap spring. use another wire to connect the tailcap body to the light's body/tube/barrel. this way, hopefully, you can measure current draw in all of the light output levels.

i haven't tried this with a Fenix, but this is the method that i've used with other lights.

 

[Bullzeyebill]

I like post #2 procedure better. Touch battery negative with - probe and un- anodized rim of battery tube wit + probe. Be sure to set DMM to 10 or 20 amp DC setting.

Bill

 

[greenLED]

That just gives you current outta the battery, not going directly to the LED. To get the latter, you'd have to take the whole thing apart and put the DMM in series right before the LED.

 

[LukeA]

That just gives you current outta the battery, not going directly to the LED. To get the latter, you'd have to take the whole thing apart and put the DMM in series right before the LED.

With Fenix's circuitry, upwards of 90% of that current is actually making it to the LED.

 

[EntropyQ3]

Thanks!
I've done some pretty careful run time measurements with known to be equal rechargeable cells (thanks to BC-900 charger). Those take the entire system into account. I'd like to cross-reference this against battery current draw.

Anyone have a good idea for the LODs? Those little beauties don't have tailcaps. It would seem as if post #3 answered this question, but I can't seem to get it to work. The threading of the Fenix heads is anodized, is that why I can't get it to work or am I missing something (I'm sure I am, this is embarrassing). Method #2 works nicely for the LxD bodies, btw.

Edit. I have a bad cold. The old greeks who thought the brain was a gland that produced snot, probably had people like me in mind. A wire between the anode and the circuit board, and pulled out past the threads to connect to the multi meter should solve the problem, right?

 

[mmmflashlights]

Yes, as you figured out my response was obviously relating specifically to lights that have no tailcap and only a head and the body. If the threads are anodized, you just have to move onto the next logical point on the head where the body would contact the head - there should be an area on the outer portion of the back of the circuit that grounds to the top lip of the battery tube in this case, so put the other probe on the outer edge of the circuit instead of the threads in this case.