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:
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:
To put it in perspective:
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.
Tom is barely around any more. :cry:
So the lvp only works when the light is turned on? Well that is a bummer. I assumed it worked all the time.
I wonder what’s causing his drain, though.
AFAIK no LVP can prevent undervoltage by parasitic drain,
Yeah, I guess that makes sense. You actually need to MCU to be operating and taking samples of the voltage in order to determine whether or not it’s above or below the threshold and that process is just going to create increased parasitic drain.
Mine was from the second batch (#501-1000), which had the first batch issues fixed. It has been working great since I got it, and it gets used quite a bit. In terms of sheer number of hours, it has probably been my most-used light over the past year, but I’m not sure if that counts since it’s a whole lot of candle mode.
Anyway, no issues at all. And the button LED has been on pretty much nonstop the whole time.
Exactly.
The MCU also has BOD (brownout detection) enabled, but that doesn’t activate until 1.8V. So, if it gets that low, it’ll shut the MCU off even more than it normally can. Which probably won’t have a significant effect on the parasitic drain.
But LVP (which shuts off at 2.8V) only works when the light is actually on. And it sounds like whatever is draining happens when the light is off. So get out a DMM and start measuring things. It’s probably a hardware issue.
I have one from the second batch. It’s been flawless in every way.
Are they marked with a number?