New user with battery/flashlight questions

Hello all,
Last week I was borrowing my friend’s no-name 1x18650 zooming flashlight and it stopped working. So I went online to get him a replacement for the no-name light and while searching for information, I found this forum.
Instead of just buying one light, I bought three; One for him, one for me, and one for my dad. They arrived today.

I wasn’t aware that my 26650 light would allow for stacked batteries. The little I know about Li-Ion and Li-MN batteries comes from me being a vaper; A former smoker now using a personal vaporizer/electronic cigarette to stay off of combusted tobacco.
Many vapers use stacked 18350 batteries in their mods, but in the interest of safety, I do not. What I’ve always been told is that when stacking batteries one needs to use them in pairs and never separating the batteries for individual use. Do I need to take this same precaution with my flashlight batteries?

Also regarding the 26650 light, my switch seems to be fickle. It doesn’t always work when pressed. Is there a particular way that I might be able to repair or mod this to make the switch more reliable?

And finally, as many people here note, this five-setting next-mode memory is incredibly annoying. On a scale of 1-10 with 1 being changing an incandescent light bulb, and 10 being ….I dunno, wiring and soldering a custom circuit board, where would you rank the difficulty in changing out this memory for one that is more user friendly?

Thank you for your time, and I’m glad to meet you all.

Pairing the 2x 26650/18650 batteries is definitely needed in flashlights.

The next mode memory situation can be fixed with a difficulty of 1. I’ll look for the thread with pictures.

Unless you want to replace the 5 modes as well, then you’re looking at a 2-3 difficulty in a driver swap.

The switch issue… Could be a few things. The couple of my lights that did it were due to weak springs that caused contact issues when the light is fully tightened. I just lived with them being 1/2 turn from fully tight and the flickering is gone.

nodnod Okay, that’s exactly what I expected to hear. In preparation for the delivery of this light I ordered a MNKE 26650 battery. It works, but I think it’s the 1500mAh version. Chances are it won’t be the long-lasting light that I was hoping it would be. Now I’m looking at a pair of red Efest 3000mAh batteries.
Are there “rules of thumb” that I need to know when selecting batteries for flashlights?

And I really appreciate you taking the time to look for that information for me.

MNKE 26650 should be 3500mAh. It’s a high drain battery, unprotected.

Really just adhere to the standard Liion safety precautions when acquiring batteries for flashlights. Don’t over discharge or overcharge.

Match the battery with your flashlights specs voltage range. Using two 18350 cells in an 18650 light may harm the driver.

You may be correct regarding the MNKE batt. I’m looking at the vendor’s page, where no mAh specs are given. I don’t know where I got the impression that it might have been 1500 mAh. (this week has been quite busy for me) Unfortunately I don’t have a way to test this at the moment.
I have a Nitecore i2 so overcharging shouldn’t be an issue so long as it’s working properly. As far as over-discharging, I’m given to think that the light output is going to be noticeably dimmed when the battery gets around/below 3.7 volts. Please correct me if I’m wrong there.
I’m slightly spoiled as my vaporizer has a voltage readout and will shut itself off at 3.2 volts.

Yeah you should be good on charging with the i2.

Many flashlight drivers will have a cutoff at a certain voltage too, best not to rely on that possibility though.

Gotcha.
I just gave the two others as gifts. It kinda shocked my buddy how strong they were. He wants another for his dad, now.
I can see how this can become a hobby. :bigsmile:

FWIW I test all my lights that claim to have low voltage protection to see if they really do cutoff/blink at 3 volts (or so). I just run the lights until they cutoff/blink and then immediately measure the battery’s voltage. I have old laptop pulls that I charge to about 3.5v for this purpose (no sense letting the light run for hours to drain the battery). If they get really really dim without blinking then I’d pull the battery and measure the voltage, but I never had a light that claimed to have voltage protection not blink at approx 3v.

That is good to know; are these lower budget lights $1-25, or the premium/expensive Nitecore/Fenix/etc?

Definitely best to check them in case of a misprinted specification.