JetBeam RRT-0 Cold Weather Operation

So it's been a bit brisk here in the Northeast of late. This weekend I took my RRT-0 with Li-Ion battery out for a walk. The flashlight was in my pocket. When I got home it wouldn't light at all. Checked the battery and there was plenty of voltage (~4.05V). After I held the light in my hand for a few minutes it came on full.

This morning I put a freshly charged *different* AW Li-Ion battery in the unit and placed it in my briefcase. The briefcase went in my car and I drove to work. The car warmed up to about 65 degrees during the 45 minute ride to work. It started out around 14. When I got to work the light was dead only re awoke after I held it for a few minutes.

So I know that Li Ion batteries aren't great for cold weather operation but this light seems to be specifically protecting them more than I would have thought. Since I can't believe the light has a temperature sensor in it I am wondering why it is so recalcitrant to light. I have never found Li-Ion chemistry to be *this* sensitive.

I need to know how this light is going to behave in the cold if I am going to trust it. Tonight I will put a Lithium primary in the light and leave it outside for an hour. If it won't work with lithium primaries then I just bought a 3-season flashlight

Anyone else have experience here?

Having just ordered a RRT-0, I'm very interested in what you find out with this thread.

Otherwise, I have nothing of any help to offer... so.... you're welcome!

I work at my local airport, and I am about 20min south of the Canadian border. Because of my job I am outside a lot, sometimes a couple hours straight. I also work nights, so it gets pretty darn cold while I'm outside.

For the last year that I have been working there, I have been EDC'ing either a Ra Twisty or a Ra Clicky. If I keep either light in the cold(talking 15*F) for about 30min or more, my lights won't power up on high. My lower levels will work, but high won't activate as the lights think the batteries are going dead. Once the lights warm back up, all levels work fine. This happens with batteries that a near full capacity. I use RCR123's in them and have noticed that primaries seem to handle the cold a little better, but they will still fail as well in extreme cold conditions.

I don't carry any AA lights on the job, but I could only imagine how bad they would stand up to the cold considering li-ion is supposed to be much better in those conditions. The one thing I do is try to keep my lights in my pants pocket closest to my body heat, that will usually keep my lights from "acting up" in the cold. Once they are out and exposed to the cold though, it won't take too long when it's 15* or colder to start acting up.

Strauss said:

For the last year that I have been working there, I have been EDC'ing either a Ra Twisty or a Ra Clicky. If I keep either light in the cold(talking 15*F) for about 30min or more, my lights won't power up on high. My lower levels will work, but high won't activate as the lights think the batteries are going dead. Once the lights warm back up, all levels work fine. This happens with batteries that a near full capacity. I use RCR123's in them and have noticed that primaries seem to handle the cold a little better, but they will still fail as well in extreme cold conditions.

I don't carry any AA lights on the job, but I could only imagine how bad they would stand up to the cold considering li-ion is supposed to be much better in those conditions. The one thing I do is try to keep my lights in my pants pocket closest to my body heat, that will usually keep my lights from "acting up" in the cold. Once they are out and exposed to the cold though, it won't take too long when it's 15* or colder to start acting up.

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You see, that's the thing. Before I became so enlightened I used to winter camp all the time in Maine. I carried a cheap flashlight with Alkaline AA batteries in it. I knew if I left it out all night it would be dead in the morning but as long as I held it in my hand or kept it in my jacket I was alright. I also noted that a 3-cell flashlight in my glove box with 5 year old heavily abused 2050mAh Duracell NiMH AAs lit up nice and bright when I got in the car after being outside in the 10 degree weather all night.

Li-Ion rechargeable are supposed to be at least as resilient as either of these chemistries and yet my trusty (?) JetBeam goes completely dead if it is even a little cold. As Lithium primaries are supposedly the best technology for cold weather and I currently have a CR123 powering a wireless radio transmitter in a weather station on the top of my garage that has never failed due to cold, If my JetBeam w/Lithium primary doesn't light after an hour in the cold, I will be forced to place the blame on the light rather than the battery technology. On the other hand, if it does light I will be obliged to engage in some more experimentation (including the same test with a NiMH AA in the tube).

I think that Jetbeam is super sensitive to the cold. My Clicky can sit outside all night and it will still work fine on my 30L level, just the highest levels will not function.

On the other hand, I usually carry my Surefire LX2 with me at work as well. This light rides in the outside pocket of my coveralls, fully exposed to the cold. I run CR123's in it, and never have problems with that light operating in the cold. Both low and high levels work 100%, ALL the time. Maybe single CR123 lights that have some sort of voltage protection are more prone to be affected by the cold? Just a thought....

Just to check I have dropped my RRT-0 in the freezer, after one hour my IR thermometer shows -16 degrees Celsius on the surface of the RRT-0 and it has no problem turning on.

Same here just pulled it out of the freezer fires right up, AW battery comes through again.:twothumbs

Alright. I gotta now toss it in the "work" freezer" with the fresh AW battery just as a gut check.

Hello Newman...welcome to CPF.

I would be interested in a test where you left just the light out in the cold but kept the batteries inside and tested the functioning of the light out in the cold with the room temperature battery. Then I would reverse the procedure and compare the results. Then we would know if the circuit board being cold has anything to do with it. I didn't think this was the case, but after reading your posts I'm wondering if it could be a factor.

I've recently been using Eneloops/Rayovac Hybrid batteries out in the cold and have been very surprised at their good cold weather performance.

Thinking beyond batteries....

"Old fashioned" incan flashlights don't have the solid state circuitry found in newer, multilevel LED flashlights. The semiconductors employed in the modern circuitry is temperature sensitive. Too, there could be a temperature sensitive solder joint.

Stuck mine in the freezer for 30 mins with an AW RCR, works fine after it comes out.

Hmm...so I just retrieved mine from the "work freezer" after 45 minutes. It was incredibly cold and didn't light. After holding it for around 15 seconds it came on full blast. When I get home I will try this with some other batteries but it sure looks like the flashlight might have a flaw.

I have had some similar results with a light that has a similar interface, the Nightcore SR3. I have been doing some ice fishing and this light has been on my belt in a holster using a AW rcr123. The light seams to be quite finicky when cold. It doesn't want to light right away. Last night this happened to me and I held on to the light for a few seconds (20) and the light fired up. Now I am certain the 20 seconds is not enough time to warm the battery through the light body using only my hands. This tells me that the cold must be affecting some part of the light other than the battery. I am not sure what it could be though. I do feel like I cannot trust this light in the cold.

I dont really know how these lights work but this is the first question that came to mind. Could the body of the light be contracting slightly due to the cold and losing connection with the selector ring?

FWIW, after reading this thread, I put my RRT-0 in the freezer @ -15° C. I have an AW RCR123a in it. I bought the RRT-0 at the beginning of December 2009 from LightJunction.

I took it out of the freezer after one hour. The flashlight would power on at the lowest level, but stayed at the same brightness when turning the ring. I left it on for 15 minutes at room temperature, with the ring on high, but it never went to the high mode. After 15 minutes, when I turned the ring, the modes worked normally. There was also some condensation.

You should try putting just the light with no battery in the freezer, than take it out and put in a battery and see if it fires up. I am curious to see what will happen. I just might try that with my Ra Clicky to see if it indeed is just the battery getting cold or not.

Ok. Back home I managed to put my RRT-0 with a quality brand new Lithium Primary in the freezer for one hour. It behaved exactly the same as the Li-Ion. 15-20 seconds in my hand and it came on full brightness. All light levels worked with no impairment. As I have had Lithium primary CR123 batteries work at well below zero I regard this as related to the flashlight.

There is an electrical lubricant that a lot of companies use on moving electrical contact parts. It is supposed to be neither a conductor of its own or an insulator. That is because in the liquid state it is such a thin film so as not to inhibit contact yet still provide lubrication and help keep contacts in good shape so that they don't readily oxidize.

However. I have had experience with this mystery fluid in the past where it collects moisture out of the air and then it will freeze and cause contacts to separate from each other. I used to find this in potentiometers that had this material in it to minimize resistor element wear from the wiper. Moisture would get in on non sealed elements over time. If the RRT uses this fluid (and the thin film amount being used would be almost invisible even if you opened up the parts) and that area is not sealed from the outside environment then eventually it could bring in moisture and have contact problems when cold beyond that of battery performance. This would not be noticeable ever if you weren't cycling back and forth well below freezing temps.

MrGman said:

There is an electrical lubricant that a lot of companies use on moving electrical contact parts. It is supposed to be neither a conductor of its own or an insulator. That is because in the liquid state it is such a thin film so as not to inhibit contact yet still provide lubrication and help keep contacts in good shape so that they don't readily oxidize.

However. I have had experience with this mystery fluid in the past where it collects moisture out of the air and then it will freeze and cause contacts to separate from each other. I used to find this in potentiometers that had this material in it to minimize resistor element wear from the wiper. Moisture would get in on non sealed elements over time. If the RRT uses this fluid (and the thin film amount being used would be almost invisible even if you opened up the parts) and that area is not sealed from the outside environment then eventually it could bring in moisture and have contact problems when cold beyond that of battery performance. This would not be noticeable ever if you weren't cycling back and forth well below freezing temps.

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That's it. MrGman is like the smartest cat I know. Seriously. Impressive.

I tried Strauss' suggestion and put the flashlight in the freezer and left the battery at room temperature.

I left the flashlight in the freezer for two hours, then I put the room temperature battery in and the flashlight worked normally.