EDCL1-T and K2 Batteries

[Elwin]

This is a long shot, but I'll throw it out here in hopes that there may be some battery nerds here who could help, so that I don't have to go join another forum. I'm all kinds of nerd, but batteries/electronics is very much not my thing.

I bought a set of K2 rechargeable CR123 batteries and the matching charger in hopes that I'd have a rechargeable solution for my Surefire EDCL1-T, which is my EDC and nightstand light. It covers both task and "tactical" roles for me. Rechargeables would be great, because I wouldn't have to play the guessing game as to when my batteries are worn down enough by tasks that I need to replace them to ensure emergency reliability.

I went with the K2s because my understanding is that they were previously sold with Surefire branding as a rechargeable option for multiple Surefire lights, including the EDCL1-T. However, on trying mine, I have the issue that I've seen reported regarding other brands of rechargeable 123s - my light will run with them on low, but high mode won't engage. High mode currently works as usual with a normal CR123.

Is there any "fix" for this, or something obvious I'm missing? Or was there a running change to Surefire's wiring that makes the light incompatible with these cells? Light was purchased in April of 2019. Thanks in advance for any advice, even if it's just "go register on a flashlight forum."

[BillSWPA]

You can avoid the CR123 guessing game with a ZTS battery tester. They make 2 versions that will test CR123: one is less expensive, and the other will test almost anything including most or all coin cells.


Sent from my iPhone using Tapatalk

[NH Shooter]

Sounds like they may not be fully charged to 3.2 volts. I would suggest a digital multi-meter to check voltage.

Thinking out loud, I wonder if that light will handle 4.2 volts....

[JCS]

I am one who has tried around 5-7 different rechargeables. I’ve asked many questions over on candlepowerforums about this light. I have the same issue as you. Did you order from surefire? I have had an order with surefire since February for their rechargeable batteries and still have not received them. They said they went to a new battery with different packaging. I’ve tried both protected and non protected cells and have tried the brands that works for other people. I think the reality is that some of their lights Made during a certain period have hardware that simply do not allow them to work with rechargeables.

[Elwin]

I assumed they were fully charged since the charger indicated they were, and stopped charging them. The batteries I bought are the K2 brand ones that a SureFire had recommended in the past and had sold with SureFire branding on them (the white and green labeled rechargeables they used to sell).

I’ve seen reports that, at least with an EDCL1-T that works with rechargeable batteries, certain 4.2v options do work. They aren’t recommended by SureFire, and you have to be sure to get one that is either unprotected or has a high enough protection threshold that it won’t block the 500 lumen high setting’s substantial draw. That’s the extent of my limited knowledge - I was trying to use the “easy button” option of getting what SureFire sold and recommended. Looks like I may just need to make do with standard CR123s as I have been though (a 16650 or 18650 option would be ideal, except it won’t fit my pockets, so I’m limited to 1xCR123 sized options). A Stiletto Pro may also be in my future when I can justify the cost.

[GyroF-16]

Also not a smart nerd, but I did find some recommendations for my EDCL-2T on the candlepower forums over a year ago when I got the light. I ordered several from batteryjunction, and this one worked the best for me. No promises on how it will work in the 1-cell light, but it might be worth a try.


It seems to allow a high draw, so the “low” mode wasn’t so dim, and the “high” mode was normally bright.
It’s the size of a 123 (as far as I can tell), but it’s labeled “IMR 16340”. I knew more about why I chose it back when I researched and bought them, but now just know that it works well for me. I carry a couple of charged spares when traveling.

[NH Shooter]

^^^Those cells are good to go.^^^

So you run a pair of them? That's 8.4 volts fresh off the charger, so perhaps one of them will not cause any harm to the single-cell light. It certainly has the current capability to run the light (more than a CR123 battery).

[GyroF-16]

So you run a pair of them? That's 8.4 volts fresh off the charger, so perhaps one of them will not cause any harm to the single-cell light. It certainly has the current capability to run the light (more than a CR123 battery).

Yep, I run 2 in an EDCL-2T. The baseline 5 lumens on low was just too dim for the task I needed it for (preflighting airplanes on very dark ramps). I need it to light up a wheel well, while saving the “high” setting for seeing the top of a tail. Those batteries brought the “low” up to maybe 15 lumens, which made it much more useable.
I own 6 of the batteries, and maybe go through two sets a year (needing recharging). I’m pretty pleased with this combination, as it makes the EDCL-2T a useful tool.

I’m open to suggestions for other batteries, though.

[Elwin]

What do you use for a charger? I may look into those after returning the K2 set I bought.

[NH Shooter]

I’m open to suggestions for other batteries, though.

Those may be your best bet.

A point to remember: unprotected IMR cells like the ones you are using are usually the same length as a standard CR123 battery, so they physically fit in lights made for CR123s. There are some really good protected cells on the market (such as these) but they are physically longer due to the addition of the protection circuit on the negative end. Sometimes they're just too long to physically fit in the light. "Duel fuel" lights are designed with a longer battery compartment to fit protected Li-ion cells and have long enough spring contacts to use the shorter CR123s. The only way to know for sure it they'll fit is to try them.

In terms of chargers, just about any of those designed for Li-ion cells are fine. I use this one.