okay good, not that i worry really it seems like a robust well built light compared to convoy l6, astrolux lights that i have etc.I feel strange it took me so long get it but never too late as u say.
I joined that group buy early and still haven’t bought one, so no need to feel strange. I’m holding out for a CW version. Sofirn might be releasing an updated version of the Q8. We’ll have to wait and see.
Mine are still going strong at this point…. no problems.
The Q8 is one of those must have lights that everyone should own.
The Q8 is actually the biggest longterm test of overdriving leds BLF-style since we started doing that in 2013. I have always wondered if 3A leds driven at 5A would eventually fry the leds, that never could be tested, and so far so good 
Very big battery drain for me.
Not switched to the working position when not used.
That’s strange. Wasn’t the switch supposed to drain next to nothing and not affect the charge for a looooong time?
The battery drain (parasitic drain) on the Q8 should be super tiny. It should take many years to drain the batteries. You can also turn off the switch lights to reduce the drain even more. Of course, if you are not going to use the light for a long time it’s best to turn the battery tube to cut all power.
Have you measured the drain on your light? What was it?
Yes, here are the specifics:
Parasitic Drain
Parasitic drain is the draw of amps (power) when the flashlight is off and the processor goes into a deep sleep mode, cutting as much power consuming features as it can, but still able to wake up when the button is pressed. Here’s the measured numbers on full or near full cells, after being off for more than 6 seconds:
- with switch LED on: 135 µA
- with switch LED off: 22 µA
In switch Lock-Out mode, the switch LED is off. There’s also a quick trick method to turn off the switch LED when the light is OFF:
- from OFF, press&hold until moon mode comes on (or hold longer)
- then quickly release the switch, and quickly click to turn the light OFF
- the switch LED should be off now even with the main LED off
To put it in perspective:
- 22 µA takes 5 years to drain 1,000 mAh, so with 4 3,000 mAh cells, it could last over 60 years, in theory of course
- 135 µA with the switch LED on takes 10 months to drain 1,000 mAh, with 4 3,000 mAh cells, it could last over 10 years
When the light is first turned off, it continues running the processor for 6 seconds, then drops into it’s low drain, deep sleep state. The amount of amps is somewhat dependent on the cells, so partially depleted cells, and cells with higher resistance will have a lower parasitic drain.
I’m far from last instance. Just my experience…
Not measured the drain.
Not used often and find critical voltage when checked.
One 30Q did not recover anymore.
That is not how it should be, there may be a current leak other than through the driver electronics. I’m curious if others have the same observation. If this unexpected high drain is a general feature of the Q8 it is wise to physically lock out the light when not in use, which would be a pity because Tom put in lot of effort to make it so low.
I have a total of 6 Q8’s - most for emergency lights - we loose power often - all sit for months at a time without any unusual drain. They all have been in use since shortly after the group buy.
I would guess this is an isolated problem.
OK. I put new battery 30Q (first use) from BG after full load and measured about 3050-3100 mAh.
After about a week (now) its about 3.96 mAh V.
I’m happy with my Q8. I bought 3 of them.
If you want to measure parasitic drain, you need a digital multi meter. You can basically do it like this:
Set your meter and test leads to milliamp. Then take a battery and touch the positive end to the driver ring, then attach the meter from the battery negative to the driver ground. You should be seeing about 0.12 milliamp with the side switch lights on.
If it’s way higher, then you have a problem with the driver or a short somewhere.
What do you mean by “one 30Q did not recover”?
Guys could I buy the driver board and switch board and fit to a SRK Clone?
Might over drive the fake leds a bit.
Are the driver diameters the same?
Make sure not to bypass the springs.
I would think heat would be the biggest issue since the clones don’t use a DTP mcpcb, plus the shelf are usually paper thin if it even has a shelf.
Check out this video David Sunshine did a while back. https://youtu.be/efl0R63-ik0 I think he piggybacked a new driver instead of swapping it. He has a lot of details.
Are you using button top or flat top batteries?
I’ve used a button top battery.
The chargers I have do not start charging this battery.
The voltage was just over 2 volts, as far as I remember.
Thanks Jason for the measurement instruction. :+1:
What I’m wondering is how the battery got down below 2.8v. This is the cutoff voltage. The driver should not draw any power below 2.8v. If it did, something seems wrong.
Does only one of your three Q8s drain the batteries fast? Maybe it has a defect in the driver? I don’t know.
Doing a drain test might give some answers.
Maybe the MCU is not going to sleep after 6 seconds like it should? I’ll ask ToyKeeper.
I think I remember that LVP detection does not work when parasitic drain is lowering the voltage very slowly. Tom would know that better though.