DEREELIGHT 3SD R2 and 1S Q4 ...driven at 2.2 A ??!!

I have tested those lights - with a 3SD R2 and 1S Q4 5B drop-ins inside - and it seems that the emitter are driven at 2.1-2.2A ???!!!

I have used a cheap - 4$ - multimeter but I have obtained credible results testing other lights : SUREFIRE E1B - 930mAh, SUREFIRE E1L - 420mAh, STREAMLIGHT POLYTAC - around 500mAh .

So , I am quite positive that the multimeter is good, though, I got those surprising results while the emitters from those drop-ins should be driven at 1.2A, according to DEREELIGHT.

I have tried 2 different 18650 cells - ULTRAFIRE and AW - .

The runtime is 1.5hrs - regulated output according to my eyes -

3SD XP-E Q5 5C take 1.5A at tailcap on mine Cl1H V4
3.8V * 1.5A = 5.7W (I expect 3.8V under load from freshly charged grey ultrafire)
Vf of XP-E driven at 1.2A is around 3.6V, 3.6*1.2=4,32W
Driver efficiency = 4.32/5.7*100 = 75%. Typical for boost regulation IMHO.
I'm confused a bit - 3SM driver on XR-E while puttin' 1.2A to the emitter consumes the same 6Watts according to CPF threads, regardless of 6V or 10V. So buck circuit driver efficiency is questionable.

People around battery threads reported 3SD 1.2A with 1h24m runtime on 2200mAh and 1h42m on samsung 2800mAh unprotected - looks like true.

Fenix TK12 claims to be one of the best regulated single 18650 light. Mine grab 990mA on the tailcap with freshly charged 18650, around 4Watts; 2200mAh of true power will leads to 7.92Wh of power, divide one to another - slightly less than 2 hours runtime on full regulation and battery will be empty. With 3SD there will be 1h22m fully regulated runtime on 2200mAh. Not so dramatical :thumbsup:

Must be a faulty driver. Other Finnish flashaholic had about the same readings some time ago.

My 3SD R2 WH takes about 1.5-1.55A from a fully charged cell.

What was the voltage of the 18650? As the voltage drops the diver will draw more current to make up for the lower voltage. At least, that's how I understand it. So if your battery was down to 3.2-3.4v, or maybe less if it isn't protected, maybe that could explain the high reading?

If the battery was fully charged, and is working properly (did you try other known good cells?), then there could be a problem with the light. I don't know if a dirty contact between the tail and the head could cause it to draw more current, but it could be a bad circuit. Does the pill get very warm or hot quicker than it should?

WadeF said:

What was the voltage of the 18650? As the voltage drops the diver will draw more current to make up for the lower voltage. At least, that's how I understand it. So if your battery was down to 3.2-3.4v, or maybe less if it isn't protected, maybe that could explain the high reading?

If the battery was fully charged, and is working properly (did you try other known good cells?), then there could be a problem with the light. I don't know if a dirty contact between the tail and the head could cause it to draw more current, but it could be a bad circuit. Does the pill get very warm or hot quicker than it should?

Click to expand...

The batteries seem OK as it follows :
ULTRAFIRE 18650 PROTECTED - 3.8V
AW 18650 - 3.8V
TENERGY 18650 - 4V
The contacts seem also OK , I have got 2.4A !! for the 1S Q4 5B , gotta do a runtime with this drop-in either.

3.8Volts on 18650 is close to discharged state, freshly charged has 4.2V +/- 0.05V *open circuit*. Under 1.5-2A load voltage drops from 3.8 to something near 3.3-3.0V, calculated to the same 6Watts. Cheap multimeters claimed 10% and more inaccuracy on 1A+ measurements - pay attention here too.

radu1976 said:

I have tested those lights - with a 3SD R2 and 1S Q4 5B drop-ins inside - and it seems that the emitter are driven at 2.1-2.2A ???!!!

Click to expand...

2.2A in is not 2.2A out.

If you factor in voltage sag and driver inefficiencies, things seem perfectly normal.