Have you measured on charge or on discharge?? 
904mAh was the charge it accepted after the first time the EC11 blitzed it. It’s currently on charge again after its second mauling - I’ll check how much charge it takes this time 
You can only measured the capacity of a battery in discharge. In charge is measured the mA that the charger send to the battery (there are losses on heat and more), not the mA that will be stored by the battery.
If the charger indicate 904 mA, perhaps the battery has a capacity of 750-800 mA. Is a good battery.
Ok - thanks, I didn’t know that.
I also use this function on new chargers. It gives an idea of the capacity and quality of the battery (It is a useful approximation)
Well the EC11 is basically a pocket rocket toy IMHO. Cool toy though!
I like this Efest - after all the abuse it has had it is still accepting a good amount of charge:
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Excellent work. How about this.
- dont confuse voltage with amount “work” left in it.
- based on your observations. When you have only two modes left you should recharge if possible. If not possible expect only a few minutes left.
problem solved.
It also seemes/seemed that the brightness dimms noticably much earlier, if you need the brightness then charge then, if not run on a lower setting and get increased runtime.
no extra equipment needed, the light tells you when it need a new battery (or recharge)
The only down side I see for this cool toy would be that the light doesn’t flash when getting down to say 3.0v. Well, and also the the PWM. Anyways, you got to expect the short run times with a 18350 pushing 900 lumens. That’s quite a load on a tiny batt.
As I said, I don’t like boost drivers with lithium ion batteries, as that is potentially more dangerous than a regulating driver that can’t drain the cell so much. On the other hand, I have read that IMR cells are not as dangerous as ICR cells.
Nothing wrong with boost drivers, if they actually add low voltage protection! Without it you have a piece of junk, no excuse for the lack of low voltage protection imo. Yes, its harder to implement in a light that also takes CR123A.
It would have to remember what type cell is in it, as a discharged lithium ion cell might have the same voltage as a CR123a. Even so, if you took the discharged lithium ion cell out and put it back in, the light would think it was a CR123a and run it down to 1.5 V. The only safe way would seem to be a user operated switch.
Do you mean “High” or “Turbo”? I am hoping those numbers are on TURBO[MAX] not HIGH!
As you can see you ONLY got 9 minutes on HIGH[?] W/ a resting voltage of 3.50v. I got 12 combined minutes on TURBO w/ a resting voltage of 3.50V. I got 3 more minutes than you!
I see you are using the Efest IMR 18350 800mah. I believe their MAX CONTINUOUS DISCHARGE CURRENT is ~ 6=A. Mine is 10.4A and has 100 less mAh yet it went 3 minutes longer than yours??!
BATTERY: EFEST IMR “PURPLE” 18350 700 mAh.
TURBO OUTPUT -I DID 3 MINUTE INCREMENTS[THAT IS THE STEP DOWN] W/ ABOUT 4 MINUTES OF REST IN BETWEEN.
TAIL STAND/NO FAN/LOFT TEMP. WAS 74F/23.3C.
STARTING VOLTAGE:4.20V* I actually used my stop watch on my phone app! STEP DOWN WAS EXACTLY 3 MIN. 7.7 SEC.!!!
3 MIN= 3.90V 6 MIN=3.74V
9 MIN=3.64V 12 MIN=3.50V
I decided to try for 3 more minutes. After an additional 2 min. 10 sec. the light stepped down to medium or low! I immediately checked w/ the DMM and it was @ 2.28v!! Needless to say when I tested my second Efest IMR 18350 I stopped at 12 minutes. Both batteries tested exactly the same.
The EFEST IMR 16340 RAN FOR 15 MINUTES[3 MIN. INCREMENTS] AND WAS @ 3.50V .It did not get as hot and certainly did not push the light quite as hard.
Yes - sorry I should have said Turbo and not Hi.
Due to your results being given to two decimal places (e.g 3.64v) I assume you were removing the battery and using a DDM to take the voltage readings.
Apart from the initial DDM reading of 4.18v before putting the battery in the light all other of my voltage readings were taken by loosening & tightening the EC11’s tail cap and counting the number of flashes. It is supposed to be accurate to within 0.1v but I think it could be worse than that especially at higher voltages as my initial DDM reading of 4.18v was contradicted with a reading of 4.0v (4 flashes) by the EC11 just seconds later. This would indicate an error of nearly 0.2v by the EC11.
I also took the post run readings immediately after each run so there was no rest period for the battery as there would have been if I had removed the battery after a run to measure it on my DDM.
If you look at my readings again you will see that the EC11 was still indicating 3.5v after a total of 13 minutes run time - so, taking into account the inaccuracy of the EC11 and the difference in runtimes and measurement method I think our results could be very close.
When I get a chance I’ll rerun the test using a DDM using the same runtime and rest periods as you did - how long after each run did you measure the voltage?
The brightness levels make more sense with a CR123 (very low 1 lumen, low 40 lumens) and the boost driver without battery protection also makes sense for that.
They built it for IMR 18350 for the 900 lumens boasting factor.
It takes a protected 16340 so I now use that or a primary CR123 unless I'm planning to show off.
Now all I need i small case to carry an 18350 in my pocket.
I haven’t got a protected 16340 - do you think you can do some runtime tests on some of the modes (say highest, mid & lowest) using this battery?
Which means that they are run down to only 10% of the starting lumens - and an unprotected Liion (Lithium cobalt or Lithium Manganese) treated like that will be drawn down to well under 2 volts i.e. permanently damaged. Half or less of the quoted runtimes for Liion would be a more practical figure for an 18350, and the runtimes for a protected 16340 which isn't as bright as the IMR 18350 are better than I expected, probably because it doesn't put out as much light.
A CR123 primary has lower voltage to start, and most are around 1300 - 1400 mah and that explains why the CR123 gives less light and lasts longer, not being rechargeable means it doesn't matter how low the voltages go because they are disposable.
My 16340 tests to about 600mah and I'll try a runtime test at high - not turbo - now.
Well that was a surprise! My protected 16340 lasted 43 minutes on high - not turbo. Its not as bright to start off as the IMR 18350 and was noticeably dimmer at the end. I checked the voltage as quickly as I could get it out of the light and it was at 3.1 volts and rising so the protection worked, as its designed to at approx 3 volts.
The EC11 is no different than any other high output 16340 or 14500 torch.
Meaning, very low capacity from the batteries, so high lumen modes will eat through the battery. Most IMR’s of this size are in the 500-70mAh range. Compare with an 18650 which is 2500-3100mAh. That’s a huge difference in runtime.
Once the battery voltage drops, so will output. I don’t suspect the EC11 is a boost driver, so once your battery drops to circa 3.9v (resting voltage), it is easy to tell visually that it isn’t as bright.
If you are only using low output modes, then there will always be sufficient voltage until way below the point you should recharge the battery. If this is your normal kind of use, then a protected ICR will be a much better battery for you. And you’ll just have to remember to check the battery voltage often.
This light w/ an 18350 IMR is very similar to my D25Cvn Ti that needs IMR 16340. I use Efest IMR 16340.They both drain the battery very fast on max. The D25Cvn will get 12 minutes of combined run time on max w/ ending voltage of 3.55v! 2 minute step downs. The EC11 also got 12 minutes COMBINED run time on max with a safe ending voltage of 3.50v
I guess what I am trying to say is that I know this, I have plenty of 16340 IMR and Three 18350 IMR specifically for the EC11. By no means do I use max all the time! You can’t ,they both get too hot.
Inconvenient as it may be at times, I know that a spare battery is at arms reach and certainly is not to bulky to carry in my watch pocket or a battery case!
Sure, it can be a pain to always be aware of the battery capacity. These are small and powerful lights and the batteries have limited capacities as others have mentioned. We have to take the good w/ the bad sometimes.
With that said wouldn’t be nice if somehow these smaller batteries could have even HALF the capacity of an 18650!
Logically, it should be pretty easy to make an 18350 with at least half the capacity of an 18650. But, I don’t know anything about the chemical composition or the construction of Li-Ion cells. Maybe it isn’t easy at all.