E2DL tail current

[afdk]

:ooo: Just looked at my Surefire (E2DL 200 lumen) tail current with a Fluke 8842A laboratory multimeter. The 123a cells are new primary Panasonic type. The current measured is 850ma at 5 seconds on high mode, low mode 32ma. The meter used is an older model, but just calibrated and has a very low burden voltage, which makes it an excellent choice for flashlight current measurement.

 

[CKOD]

What is the resistance used? It might be having more of an effect then you think. If the manual I pulled up is the right one, they list the 8842 as only going upto 2A dc, and the burden voltage as "<1v" (annoying, just tell us what resistance shunt you use on that range...)

My agilent 34401 on my desk uses a 5 ohm resistor for the miliamp range, and a .4 ohm resistor for the 3A range, 1V burden for 2A would suggst a .5 ohm shunt for the 2A range on the fluke bench meter, which would have been ~.4v on high.

VS a typical handheld DMM with a 10A shunt ( ~.03 ohms on my fluke 73) , which actually makes it a better choice for current draw measurements. Evenmore so on direct drive LED lights where any voltage loss drops current by a lot.

PS: Did someone get a new benchtop DMM and is having fun playing with it? Or just bored at work? ;) Find something to use as a current source, and string the fluke and a handheld meter in series and check (or calibrate if you dare venture inside) the handheld meter :D

 

[afdk]

Ok, the Fluke 8842a has an easy way to measure its burden voltage. By doing this it turns out to be about .4v as you thought. I included this in my calculation and it added about 71ma more to the indicated 850ma. 921ma is much closer to the real current draw. Thanks for your input.

By the way, not bored at work! Just received the Fluke from metrology and deceided to play with it a little bit.

 

[Lumencraft (Matt)]

Hi afdk. Do you happen to have a pair of rechargeable 123 cells? If so could you tell me what the current draw is on RCRs?

 

[Howecollc]

Hi afdk. Do you happen to have a pair of rechargeable 123 cells? If so could you tell me what the current draw is on RCRs?

My older 120 lumen E2DL pulled 600mA on high and 70mA on low from a pair of AW 3.7v RCR123s.

The numbers I got with a pair of almost new Surefire CR123s were 810mA on high and 20mA on low. My 15 year old Craftsman 82017 multimeter, however, can't claim much pedigree.

 

[gilchristobin]

If so could you tell me what the current draw is on RCRs?

 

[Retinator]

Well that explains why my E2DL gets fairly warm on long runtimes on high.

Helluva light!