Electronics, Lighting, & Gadgets - CR123 Rechargeables + Cold Weather

I got a couple of the Fenix lights along with a kit of 4 rechargeable CR123 cells and a smartcharger. Riding in the cold of Minnesota, on one of the higher settings, the lights will just cut out on me. The batteries aren't dead - they just seem to react to the cold. If I turn them off a while, or drop to a dimmer setting, or get them home and inside the warm house, they do fine. The cells are "Tenergy". Any tips? Why more problems on the high settings than the low? Would I do better with standard disposables instead of the rechargeables?

Try insulating the light. If it gets cold enough any batteries will give you a problem it's normal. How cold is it?
If you get stuck and need just a little more light, put the whole thing under your jacket for a while. That will warm it up temporarily. If it's not too inconvenient you could always keep a pair of batteries under your coat and switch them. Which light do you have? If you can ride with one light, keep one under your jacket until the other one gets too cold. How long do you need to ride, are you commuting?

Well, this doesn't seem normal - so that's why I posted seeking some info. The lights just go blank without warning. It's cold in Minnesota. The lights - the new P2D Premium Q5's were intended for my commute, and I have one on a helmet mount and one on the bars. It's not feasible to keep rotating them or swapping batteries -that would kind of defeat the purpose. If I had to stop several times on my commute to change lights/batteries, I'd just say to hell with it and probably just end up riding dark like I have had to a couple of times when they gave out on me. I got these as my lighting solution, but so far it has just been a PITA. I gave up and put an old Cateye EL-520 (4 AA batteries) back on the bar -- it doesn't throw enough light to help me see where I'm going, but at least I know I've got something that isn't going to cut out so drivers can't see me.

So what I was really trying to find out was if there was something about the CR123 rechargeables in particular that has some particular history of problems or some particular sensitivity to cold. Anyone know anything about that?

Well, this doesn't seem normal - so that's why I posted seeking some info. The lights just go blank without warning. It's cold in Minnesota. The lights - the new P2D Premium Q5's were intended for my commute, and I have one on a helmet mount and one on the bars. It's not feasible to keep rotating them or swapping batteries -that would kind of defeat the purpose. If I had to stop several times on my commute to change lights/batteries, I'd just say to hell with it and probably just end up riding dark like I have had to a couple of times when they gave out on me. I got these as my lighting solution, but so far it has just been a PITA. I gave up and put an old Cateye EL-520 (4 AA batteries) back on the bar -- it doesn't throw enough light to help me see where I'm going, but at least I know I've got something that isn't going to cut out so drivers can't see me.

So what I was really trying to find out was if there was something about the CR123 rechargeables in particular that has some particular history of problems or some particular sensitivity to cold. Anyone know anything about that?

It's totally normal, it's the cold. The CR123 batteries are better in the cold,than other types for a bike light. That's just life. It depends on the temperauture. The colder it is the worse it will be. If you have a light with a high current draw (like the P2D), that makes things worse. A low current light like the Cateye will work for a while but eventually that will quit in the cold too. For extreme cold an insulated water bottle battery will stay warm longer. The lithium batteries tend to keep going and then shut off, as opposed to alkalines that just fade as soon as they get cold.

So what you get from the lithium batteries is a shorter run time, the keep going at full brightness and then just die, instead of just fading away. This is better for a bike light when it is not so cold they don't work. All you can do is be sure they are good batteries and keep them warm enough.

You could try a light with NimH batteries, but I don't think there is any NimH battery to fit the P2D.
All I can say Is, they all won't work anyway if it gets cold enough. They all will work better when it gets closer to 40 degrees. I don't see that happening soon where you are. Cold stops chemical reactions.

It's totally normal, it's the cold. The CR123 batteries are better in the cold,than other types for a bike light. That's just life. It depends on the temperauture. The colder it is the worse it will be. If you have a light with a high current draw (like the P2D), that makes things worse. A low current light like the Cateye will work for a while but eventually that will quit in the cold too. For extreme cold an insulated water bottle battery will stay warm longer. The lithium batteries tend to keep going and then shut off, as opposed to alkalines that just fade as soon as they get cold.

So what you get from the lithium batteries is a shorter run time, the keep going at full brightness and then just die, instead of just fading away. This is better for a bike light when it is not so cold they don't work. All you can do is be sure they are good batteries and keep them warm enough.

You could try a light with NimH batteries, but I don't think there is any NimH battery to fit the P2D.
All I can say Is, they all won't work anyway if it gets cold enough. They all will work better when it gets closer to 40 degrees. I don't see that happening soon where you are. Cold stops chemical reactions.

That doesn't make any sense. A good lithium battery should handle the cold.....that's one of its main attributes. How cold are we talking here??? I use my Cygolite DualCross (at its highest setting) with rechargeable lithium ion and I ride quite often at sub zero temperatures for over an hour (with no insulation around the battery strapped to my handlebars) and have never had a problem. Same with the lithium AA's I use in my headlamp at their highest setting. I'm not familiar with the CR123's and their susceptibility, but it sounds to me like more of a problem with circuitry or with the individual set of batteries you're using.

That doesn't make any sense. A good lithium battery should handle the cold.....that's one of its main attributes. How cold are we talking here??? I use my Cygolite DualCross (at its highest setting) with rechargeable lithium ion and I ride quite often at sub zero temperatures for over an hour (with no insulation around the battery strapped to my handlebars) and have never had a problem. Same with the lithium AA's I use in my headlamp at their highest setting. I'm not familiar with the CR123's and their susceptibility, but it sounds to me like more of a problem with circuitry or with the individual set of batteries you're using.

It depends on how much power the light needs to work compared to how much the batteries can deliver. It depends on how long they ran before they died. It depends on the total capacity you have, how much your light draws and how long it should go etc. etc. The P2D only goes one hour on it's highest setting. He did not say how long they went before cutting out. It makes perfect sense, you're not comparing apples to apples. I already said they are better than the other types of batteries. We don't have enough info to compare your situation to his. It's too complicated to get enough info. Relative to what they are doing his batteries might be handling the cold great. If it's supposed to go an hour and it's going 50 minutes that's pretty good. He didn't say how cold it is, or how long the light ran. He said if he turns the light to a dimmer setting thay are fine. That's not the same as being dead, that's just reduced power in the cold.

The batteries are new - I bought them along with a smartcharger at the same time I got the lights as I previously had no devices using CR123 cells. I can put a fresh charge on them, and have them cut out within just a few minutes (literally - 2-3 minutes) of operation at the higher settings. We're talking the full range of winter-time temps in MN. I've had it happen everywhere from 0-40. Don't think I've been below zero, but maybe - if not, it could happen any day. My typical commute is about 7.5 mi one way, so I'm looking for them to stay operational for at least 1/2 hour, give or take. The lights still cut out on the lower settings, but not as quick. And it's not that they're going dead because I've used them to the point of draining the batteries -- we're talking freshly charged batteries, and once I get them home and warmed up inside, I can turn them on and they'll run for hours. I fully charged and then completely depleted the batteries several times to condition them.

The cells are 3.0v, Lithium Ion, 900mAh. Ultimately what I'm trying to figure out is whether I've got defective lights or cells, or whether this is typical for these things -- in which case I have purchased stuff that is entirely useless for the purpose for which I need it. When I read the posts on the Fenix lights, and looked at their website, I saw them promoted extensively for biking use, but never saw anything that mentioned that I could have problems with them in cold temps.

Are the batteries protected ?

The CR123 batteries are better in the cold,than other types for a bike light.

You say they're better, but they don't work even as well as the 4 AA's with the Cateye. I needed "better" because I needed more lumens/brighter lights. That's the frustration. And I would emphasize again that we're not talking about depleted batteries -- they still have plenty of charge left on them when they're cutting out.

Are the batteries protected ?

Not sure what you mean.

In regard to lithium batteries and the cold.
I have a Chaney Accurite refrigerator/freezer digital remote thermometer. The refrigerator sending unit uses standard AA alkaline batteries. Temps run between 35-37 degrees. No problems.
The freezer sending unit will not work very long with the AA alkalines. Manufacturer recommends lithium. I bought Energizer lithiums and have been good for months and months. Freezer temp is about -5 to -9 degrees 24/7x52. They will cost more but will work in sub zero temps.

Some batteries have a protection circuit fitted to one end. These look nearly exactly like unprotected batteries.

It could be that the protection circuit doesn't like the cold, if your batteries have them.

Or it could even be the fenix that doesn't like the cold, the torch itself is going to be colder than the batteries......

I have a camcorder that uses nimh and doesn't work in the cold.

The manufacturers recommended solution is to use lithium cells instead as they don't mind the cold.

I suspect the torch...;)

OK - so if I'm understanding the replies correctly, and given that these are Li-Ion cells without a protection circuit, I really shouldn't be having these kinds of problems in the cold. So I've got something unusual going on - like maybe defective cells, or a torch (? - not sure I follow this) that doesn't function in the cold. Right?

Are the batteries protected ?


OK - so if I'm understanding the replies correctly, and given that these are Li-Ion cells without a protection circuit, I really shouldn't be having these kinds of problems in the cold. So I've got something unusual going on - like maybe defective cells, or a torch (? - not sure I follow this) that doesn't function in the cold. Right?

If I recall correctly in my email to Fenix Store before (can't find email rihgt now) they said they sell 'protected li-ions'. This was probably back ~1.5yrs ago when I emailed to ask. If I remember reading right there is something about over depleting li-ion cells that causes them to mal-function. Just incase of foggy memory, I could be wrong on that. Chances are the cells are 'protected' or the flashlight is faulty.

From my quick reading of this thread it seems the OP may not know too much about cells and I was going to suggest testing with a digital multi-meter. A simple test to know if it is the batteries or not is go to say Walmart (probably the cheapest place to get this real world and most poeple know of) and buy 2 x C123 lithium batteries (check package date for expire date, probably better to go with Energizer if you need to resell or backup use). Take your batteries with you when you're shopping. It's been a long time since I've checked on those cells in the store (I'm in Canada so CDN price) but I think a pair will cost you ~$5-7 CDN or ~$3-5 USD I think. Small price to pay to test.

Put the one time use cells in your light (aka torch) and use normally while riding. If the light works normally like it should then that would point the issue at your CR123 rechargeables which may be 'protected' or faulty. If the light cuts on you like before then you know it's your light that s faulty and I would look into having it fixed.

If the light is fixed, keep the one time use cells as backup emergency. Take a photo of your batteries a couple angles then post here and send to the store you bought it from to check if they are 'protected'. Still you'll need to test with a set of non-rechargeable cells to see if the light is faulty. If you know of any security guards/cops as friends see if you can buy a set of C123's off them for cheaper as C123's tend to be common with that profession.

Disclaimer: I don't own a Fenix light or CR123 cells or any light that uses CR123 cells nor do I work for Energizer. This is just some basic troubleshooting to narrow down the problem and applies to any light.

Hope that helps.

The batteries are new - I bought them along with a smartcharger at the same time I got the lights as I previously had no devices using CR123 cells. I can put a fresh charge on them, and have them cut out within just a few minutes (literally - 2-3 minutes) of operation at the higher settings. We're talking the full range of winter-time temps in MN. I've had it happen everywhere from 0-40. Don't think I've been below zero, but maybe - if not, it could happen any day. My typical commute is about 7.5 mi one way, so I'm looking for them to stay operational for at least 1/2 hour, give or take. The lights still cut out on the lower settings, but not as quick. And it's not that they're going dead because I've used them to the point of draining the batteries -- we're talking freshly charged batteries, and once I get them home and warmed up inside, I can turn them on and they'll run for hours. I fully charged and then completely depleted the batteries several times to condition them.

The cells are 3.0v, Lithium Ion, 900mAh. Ultimately what I'm trying to figure out is whether I've got defective lights or cells, or whether this is typical for these things -- in which case I have purchased stuff that is entirely useless for the purpose for which I need it. When I read the posts on the Fenix lights, and looked at their website, I saw them promoted extensively for biking use, but never saw anything that mentioned that I could have problems with them in cold temps.


As you already pointed out, they work when they get warm again. I knew that was going to happen, you already answered your own question.
You pointed out that they run longer on lower setttings, I knew that was coming too. It's the cold.
You could try a different brand of rechargeable, but I expect the same results anyway. It's the whole setup, not just the batteries.


That light (P2D) really stresses the battery, much more than many lights. Everything has to be just right to deliver all that power. The cut off point will depend on the applied load, and the temperature. It's not the same in all circumstances.
The batteries can't supply the needed power for high setting at that temperature, but will supply a little less. If you don't understand, try another pair of batteries. If you don't know if it's 40 degrees or zero degrees when the batteries die, you won't learn anything. The single cell 123 lights stress the batteries more than some of the 2 cell 123 lights.

Non cyclists (flashlight sellers) don't think people will ride in the cold below freezing. They won't talk about it. Also each light can be different. It's way too complicated, to make a general statement about it.

Try non rechargeable Duracell batteries as a test. Some brands are better than others. Don't try unprotected rechargeable batteries in a case like this. The protection is there for a reason. I don't expect this combination of light and battery to work below freezing. I would expect shorter runtimes around 40 or below.


You say they're better, but they don't work even as well as the 4 AA's with the Cateye. I needed "better" because I needed more lumens/brighter lights. That's the frustration. And I would emphasize again that we're not talking about depleted batteries -- they still have plenty of charge left on them when they're cutting out.

Yes, but I also pointed out that it depends on the applied load. The load on the other light is not stressing the batteries as much. It's not just the batteries it's the high load from the P2D light too. It makes perfect sense, nothing is odd or strange, it's exactly what I would expect.

If I recall correctly in my email to Fenix Store before (can't find email rihgt now) they said they sell 'protected li-ions'. This was probably back ~1.5yrs ago when I emailed to ask. If I remember reading right there is something about over depleting li-ion cells that causes them to mal-function. Just incase of foggy memory, I could be wrong on that. Chances are the cells are 'protected' or the flashlight is faulty.

From my quick reading of this thread it seems the OP may not know too much about cells and I was going to suggest testing with a digital multi-meter. A simple test to know if it is the batteries or not is go to say Walmart (probably the cheapest place to get this real world and most poeple know of) and buy 2 x C123 lithium batteries (check package date for expire date, probably better to go with Energizer if you need to resell or backup use). Take your batteries with you when you're shopping. It's been a long time since I've checked on those cells in the store (I'm in Canada so CDN price) but I think a pair will cost you ~$5-7 CDN or ~$3-5 USD I think. Small price to pay to test.

Put the one time use cells in your light (aka torch) and use normally while riding. If the light works normally like it should then that would point the issue at your CR123 rechargeables which may be 'protected' or faulty. If the light cuts on you like before then you know it's your light that s faulty and I would look into having it fixed.

If the light is fixed, keep the one time use cells as backup emergency. Take a photo of your batteries a couple angles then post here and send to the store you bought it from to check if they are 'protected'. Still you'll need to test with a set of non-rechargeable cells to see if the light is faulty. If you know of any security guards/cops as friends see if you can buy a set of C123's off them for cheaper as C123's tend to be common with that profession.

Disclaimer: I don't own a Fenix light or CR123 cells or any light that uses CR123 cells nor do I work for Energizer. This is just some basic troubleshooting to narrow down the problem and applies to any light.

Hope that helps.


Helpfull suggestions however, he has two lights doing the same thing. They each take one battery. It is reacting approximately the same way my identical light reacts. That's 3 out of 3. I would say to follow your sugestions anyway, just in case. He points out that they work fine when they get warm again. That light has a high drain on the one battery.

I would almost be willing to bet a 7 C cell mag light it's the cold, maybe not. :D

OK -- I'll give the troubleshooting process suggested by ZE a try, but if it turns out that 2many is right, then these lights are just worthless to me and I will return them. What good is a light that you can't use 6 months out of the year. Seems like as much as you hear about these supposedly great Fenix lights, that there would be some mention of the fact that they only work about half the time.

OK -- I'll give the troubleshooting process suggested by ZE a try, but if it turns out that 2many is right, then these lights are just worthless to me and I will return them. What good is a light that you can't use 6 months out of the year. Seems like as much as you hear about these supposedly great Fenix lights, that there would be some mention of the fact that they only work about half the time.

There are a few Fenix L2D Q5 owners on the forums. They will run on NiMH, Lithium, or alkalines. You could ask if anyone has experience running them say, below freezing. You would have to try and be acurate about the temperature. That light has two batteries and does not draw anywhere near what the P2D does. But it uses AA batteries. I don't know what the results would be.

I have one here now.
It is 14 F outside now. I will try it outside with two Nimh and see what happens in an hour.

Start 9:38.......two Eneloops...14F...I'll edit this post in about an hour.
10:17 .....no changes...looks fine
end 10:39......no changes...looks the same..now it's 16.2 F....
I have no idea what would happen at zero or even 10 degrees. It might be zero when I get up in the morning.


I would put my P2D out there with a 123 battery..except... I already over discharged a battery in that light and it popped and vented dangerous gas when I was holding the light inside the house. All I did was try and run the light on high with the battery being too weak. It might have been due to a cheap brand battery.Those batteries can be dangerous, the gas can kill you. I'm afraid to leave it on for too long. Actually, I don't use that light anymore.

I've had no problems using lithium rechargables in the cold.

Exactly which batteries and charger are you using, and how cold is it?

I've had no problems using lithium rechargables in the cold.

Exactly which batteries and charger are you using, and how cold is it?

I noted the brand of batteries above, but here is the link to the exact battery/charger combo that I purchased. http://www.batteryjunction.com/4parc390reli.html I was wrong earlier when I stated that I didn't believe they were "protected". I see in the description that they are listed as having internal voltage regulators and full PCB protection against overcharging, etc.

I also noted the temperature range -- you know, it's Minnesota, it gets cold here -- I need something that I can rely on even when it gets below zero. If this won't do it, then I need to find something else.

I've had no problems using lithium rechargables in the cold.

Exactly which batteries and charger are you using, and how cold is it?

Unless it's a P2D Q5 in the same temperature it does not matter much. If it's a light with two batteries the load is different. One needs to dupicate the load, the temperature, the thermal mass of the light and the battery at least.

If it is a P2D what brand of batteries are you using?

I would almost be willing to bet a 7 C cell mag light it's the cold, maybe not. :D

Dont make me come and tape Baileys ears down! :love::roflmao2:;) Haha.. I can't believe you remember that 7 C maglight joke. :D BTW you need a video of you riding with Bailey as a tailgunner and his shades on. I so want to see that. ^_^;; Cuteness. :love:

You know, if would be great if Fenix or some thrid party sold tail caps with an on/off switch and cable out the end for the PxD series so you can put your batteries into a battery pack for longer runtime and to keep the cells warmer by a slightly larger mass of battery in a battery pack for longer runtimes and less drain per battery.

Say 2-4 x CR123 batterypack wired in parallel. :) I don't think the OP would know how to make that but just an idea to those with a novice understanding of electronics or light tinkering.

Then again it is an external battery then and not internal so you may want to get something like this http://www.amazon.com/Polar-BB-TRZ-TNi-TRZ-Bento/dp/B000W1NMM0/ref=pd_sim_sg_3 which is a spin off of the Bento cycling bag. They come in many sizes from large to small. A small one could hold a battery pack in there. Many companies make a version like that. I have one by Axiom (Norco) tho Topeak has some nice ones as well and some comes with a open mesh top or rain cover top. The cases are mostly black so it would match the bike. Just an idea to look into. Comes off the bike easy and you could find some for ~$8-12 CDN/bag so getting 1-2 may be a good idea incase one gets stolen it's not a huge loss.

Dont make me come and tape Baileys ears down! :love::roflmao2:;) Haha.. I can't believe you remember that 7 C maglight joke. :D BTW you need a video of you riding with Bailey as a tailgunner and his shades on. I so want to see that. ^_^;; Cuteness. :love:


:thumb: :lol: Do you happen to own a machine gun?



You know, if would be great if Fenix or some thrid party sold tail caps with an on/off switch and cable out the end for the PxD series so you can put your batteries into a battery pack for longer runtime and to keep the cells warmer by a slightly larger mass of battery in a battery pack for longer runtimes and less drain per battery.

Say 2-4 x CR123 batterypack wired in parallel. I don't think the OP would know how to make that but just an idea to those with a novice understanding of electronics or light tinkering.

Then again it is an external battery then and not internal so you may want to get something like this http://www.amazon.com/Polar-BB-TRZ-T...ef=pd_sim_sg_3 which is a spin off of the Bento cycling bag. They come in many sizes from large to small. A small one could hold a battery pack in there. Many companies make a version like that. I have one by Axiom (Norco) tho Topeak has some nice ones as well and some comes with a open mesh top or rain cover top. The cases are mostly black so it would match the bike. Just an idea to look into. Comes off the bike easy and you could find some for ~$8-12 CDN/bag so getting 1-2 may be a good idea incase one gets stolen it's not a huge loss

A long time ago I had an inexpensive light that had a remote battery pack that held 5 D cells. To make it operate with alkalines in the cold I used to put the pack under my jackets. It worked great.

I always thought that insulalting a small handlebar light with large diameter pipe insulation and putting a chemical hand warmer under the insulation would work too. One would have to be sure it did not get too hot somehow. That might work with a small remote pack too.