ARC AAA in cold environments

Hi *,

just came back from my daily commute to work with my bicycle. At home in the garage I took my
ARC AAA an ... nothing happend. I tried to threw
out the head (this helps normally if the ARC
won't turn on) and back. But nothing happend.
After a view min's in the warm room the ARC worked again. Outside temperature was about -2°Celsius. I will try it again tomorrow with a another battery. Is there more experience operating an ARC AAA in coldy conditions?

Ralf, still impressed from the ARC AAA ...

A few members have frozen them in solid blocks of ice and they still worked.

that is strange...the battery must be at fault.

Cold? Yeah, mine worked OK, as seen here:

http://www.candlepowerforums.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=31;t=000450#000000

I was just about to post my problem on this forum when I saw this thread. I had a similar experience as ralf on Tuesday when i was running through the woods to keep my stamina up. I do this several times a week after my other training exercises and in autumn and winter this means that i have to cope with darkness.
Having used a flickering M*n* (r@p L*** to guide me through the dark places for quite a long time, it finally became too much of an annoyance due to its poor reliability and I decided to look around on the internet for something new being small, sturdy / water resistant, long-term cost effective, with kubaton-like impact weapon capabilities and last not least 99,99% reliable. Guess what I bought, right, an ARC AAA.

Until Tuesday the AAA has always served me well during the several months that i now own it and was perfect for keeping a high pace because of its little weight and small size. The beam was bright enough to light up several meters in front of me so I could see where I was running and if there where any obstacles like fallen trunks or branches in the way, while not inflicting too severely on my night vision capabilities.
We had a significant temperature drop in Germany over the last days and after having made approximately 1/3 of my 8 km run I reached a relatively bright area and decided to turn the little critter off to allow my eyes to completely accommodate to the ambient light. A minute later I reached some more difficult terrain and turned on the AAA again. I wont repeat the curses that came out of my mouth, as this would probably result in an immediate ban from this forum, but i can ensure you that I got really pissed when I realized that the AAA stayed dark and I was running near a 5 meter slope. Immediate HALT! Checking all systems... Twisting the head back an forth several times didn't bring the desired result but warming the AAA in the palm of my glove finally made the light come back.

Since then I have made numerous experiments to distil the cause of this unpleasant behovior of my formerly beloved AAA (reminds me of some girls

The 2 factors necessary for this behavior to be reconstructed:
1) ARC AAA being exposed to a cold environment for some time (the temperature was about -5°C [22°F] in the woods)
2) ARC AAA being turned off for at least a minute

*I can definitely rule out the battery. I tested several of my usually used NiMHs as well as a fresh Duracell Alcaline. Either the light didnt work at all or worked at full brightness after being warmed up a little. No weak beam as a result of missing battery power.

*I examined the grease of the threading, as I could recognize a significant increase in the amount of power necessary to twist the head (the increase might have also been caused by the reduction in diameter of the AAA body as a result of the aluminium cooling down). I normally use 100% silicone spray, but also tested without any grease and with graphite powder (I suspected the chemkote finish to maybe have an exponentially growing electrical resistance at lower temperatures and expected the graphite powder to permit the current to flow again by granting contact between points where the chemkote might be worn off). To no avail.

*I used a q-tip to clean the contacts of the ARC AAA with ethanol in order to remove any possible stains. No positive effect.

*I put only the head with a battery in the deep freezer at -20°C [-1°F] and used a bent paper clip to make contact between the minus pole of the battery and the threading of the head. I got light at about 50% of the times I tried this.

There is one fact that is particularily interesting: When the cooled down AAA doesnt work after being turned on and the head is left in the on position while the flashlight is brought back to room temperature it won't light up later. The head has to be turned back and forth for it to work again. All that i can say is that i am puzzled and also considerably disappointed not only because i would never ever have expected this to happen but also because I coundn't yet find out the exact reason for this behavior. I hightly suspect it to be some "low-temp-hi-resistance thingy" :-| My main suspect is the contact of the head which connects to the plus pole of the battery. I think i have the version 3.1 model because of the packaging describing it to be water resistant to 50ft.

Any help is appreciated. Thx in advance...

Originally posted by darell:
Cold? Yeah, mine worked OK, as seen here:

http://www.candlepowerforums.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=31;t=000450# 000000

Click to expand...

<font size="2" face="Verdana, Arial">thanks for this link. really cool

I changed now the old battery (which I was to empty with the ARC AAA) replaced it with the original duracell and it worked properly again
in cold environment.

another thing about the ARC AAA frozen into
a block of water is that frozen water is about
0°C. My ARC AAA was about -2.

Therefore I wondering about how deep the
dc/ dc converter can be operated.

Cheers
Ralf

I have used my Arc at -30F with no problem.

I actually did this, briefly:

I left my Arc AAA in liquid nitrogen and it was fine

Click to expand...

<font size="2" face="Verdana, Arial">I was concerned about temperature differential causing a boiloff eruption, so i first placed the Arc in the freezer for about an hour, then just prior to the N2 immersion I sprayed it down with Verruca Freeze. I dunked the light for a five count in a double Styrofoam cup one-third full of liq. N2; there was minimal bubbling and hissing.

To slow-warm I sprayed again with Verruca freeze, placed in the freezer for half an hour, then the fridge. Light worked fine; I suspect the brief dunk avoided battery freeze, as I intended. LED and circuit survived the thermal shock--longevity after this may be questionable.

Should have taken some pix, but didn't want to contend with juggling the digicam and LN2 nor extend the dunk. Employing another for assistance would have subjected me to endless derision from the non-flashaholics around here, unlike the understanding like-minded forumites 'round here.

ShouldI repeat the test and document with pix? Hmmm...do I feel lucky? Well, do ya.....?

Regards,

PDQ

I left my Arc AAA in liquid nitrogen and it was fine

j/k

I have used mine at -2F and had no problems. This could be a result of different batteries.

Wow! Liquid N2 ... I doubt that Peter has considered this test . . . yet.

Pictures of a follow-up test would be very appropriate, provided you can dodge the non-flashaholics of course.

Now Peter can advertise "Wayyyyyy Coooooool lights!"

Hi beasty boar,
this sounds like a candidate for the roll-crimp .

If that fails, you will have to send it to Peter and you'll get a replacement.

I got to experience this phenomena this morning. Last night I inadvertently left my Arc in my car. (Mid-Michigan) This morning when I got it I found that it would not turn on. I checked the contact to ensure it was clear, and it still would not light.

So having read this thread I decided to conduct a little research to see how warm it had to get before it lit and if the beam would be weak when it first came on by leaving it "on" while warming it in my hands and between my thighs (manual transmission=both hands) during the 25 minute drive to work .

By the time I got to work it still had not lit. It felt warm to the touch so I knew that it was warm enough, so I turned it off and then back on and this time it lit.

This makes me strongly suspect that the cold vulnerability is somewhere in the circuitry since something obviously prevented it from lighting, despite being warm enough, until it was turned off first.

Originally posted by MichiganMan:
This makes me strongly suspect that the cold vulnerability is somewhere in the circuitry since something obviously prevented it from lighting, despite being warm enough, until it was turned off first.

Click to expand...

<font size="2" face="Verdana, Arial">It's not unusual for a power supply to shut down when the input voltage is too low and not restart until power is cycled off on the inputs. Surely there can't be that much to the AAA DC-DC converter but you never know.

Eveready rates their batteries to operate down to 0F. But, the battery becomes useless as the temperature gets that cold.

I suspect that if you want a reliable light at those cold temperatures you need to go to a Lithium light, Even if there is a problem in the ARC AAA and Peter fixes it that wouldn't solve the Alkaline battery problem.

Originally posted by MichiganMan:
I got to experience this phenomena this morning. Last night I inadvertently left my Arc in my car. (Mid-Michigan) This morning when I got it I found that it would not turn on. I checked the contact to ensure it was clear, and it still would not light.

So having read this thread I decided to conduct a little research to see how warm it had to get before it lit and if the beam would be weak when it first came on by leaving it "on" while warming it in my hands and between my thighs (manual transmission=both hands) during the 25 minute drive to work .

By the time I got to work it still had not lit. It felt warm to the touch so I knew that it was warm enough, so I turned it off and then back on and this time it lit.

This makes me strongly suspect that the cold vulnerability is somewhere in the circuitry since something obviously prevented it from lighting, despite being warm enough, until it was turned off first.

Click to expand...

<font size="2" face="Verdana, Arial">Well if you're in Mid Michigan it was -18F there one morning two weeks ago. So if that was the morning I would think that the battery could have easily frozen up.

Where does one get a hold of liquid nitrogen for their own experimental uses?

Thx for the hint B@rt. Although I don't think that this would remove this special problem, that sure is a fine service manual PG made and so I had to bookmark it of course

I've conducted some more extensive testing in the freezer at -20°C (= -4°F; this time I used my pda to convert the value, which is more accurate than the estimate in my first post) over the last couple of days. In order to address the hard to twist head issue I mentioned earlier, I used more silicone spray than was necessary for smooth twisting under warm conditions. This removed the twisting problem. Besides it also significantly increased the probability of the ARC lighting up.

My empirical results are the following:
Out of the 20+ times (I was too much of a lazy turd to take notes, so the following figures are estimates) I let the ARC cool down in the freezer for at least 10 mins (I sometimes forgot it there for 1 hour or more - the overall period of time in the cold seems not to play a big part once the ARC is cooled down), it lit up immediately at about 50% of the times and also kept lighting up again and again after each 10 sec interval I tested it during the first 2 mins of the warmup process. In 25% of the cases, it worked like a charm when I took the flashlight out of the freezer, but then refused to work somewhere within the first 2 mins. The remaining 25% were immediate failures. I used both NiMHs and the almost unused Duracell the ARC was shipped with. I didn't find the battery type or individual cell to have a discernible influence on the results.

I made a considerable advance in narrowing down the cause of the problem:
Each and every time the light failed, I was able to make it work again by twisting the head completely out (without taking it off) and then exercising a wee pressure on the head (directed towards the body) while I keep on twisting to make the beginnings of the threadings of the body and the head click slightly whenever they meet (this cleans their surface). 2 clicks are enough for the ARC to function again after turning the head back to operational position.

Conclusion:
I see a high probability that the cause of the malfunctions lies in an insufficient electrical contact between the 2 threadings under certain circumstances (mainly the cold environment). Why this happens, I don't know. As I'm not an expert in metallurgy, I can't tell if this might be a result of the behavior of the aluminium alloy used (i.e. I dunno if this aircraft aluminium contains Pb for increased hardness). I also don't know enough about the low temperature properties of chemkote and the silicone spray I use (it says 100% silicone so there should not be too many other substances involved except for a possible residue of the propellant) and their possible interaction with the alloy to make some binding statements. Maybe someone else can tell...

I would like to know if more people can or can't (this is relevant as well) reconstruct the same behavior of the ARC (which version, what kind of grease).

BB,
I still think this could be a problem the roll crimp might fix, judging your description. The only other thing I can think of is a problem with the converter starting to oscillate...

My advice would be to perform the roll crimp, see if the problem is gone, and if not, contact Peter Gransee. Either way, I'm sure this problem will be resolved.

btw, Welcome to CPF! ( I almost forgot... , one of the friendliest boards out there! )