Would you have this emergency torch?

Caver747

New member
Hi guys,

I've got this concept of a flash light that would be used only in emergency when being stuck in a cave. It would be a little torch that's able to emit light for at least 1 week continuously, so you won't be sitting in dark until being rescued. Regarding it's size, it could easily fit in a small pocket.
I know, that some headlamps have this function, but this would be dedicated, always fully charged, and really cheap. What do you think of the idea, would you have it with you? Or have you seen or got something like this yet?
 

tomferry

Well-known member
I personally carry a wowtac a2s as my spare and a spare battery for this , I have had the torch many years and it?s really been outstanding for its price ?30 , I have viewed Pete?s link I could not see it?s battery life ? I no my scorpion x12 has a massive battery life on its lowest setting this is a Roy fellows torch .
 

royfellows

Well-known member
Well yes, I saw no burn time for the Petzl which is essential information that is just not there.
The praise for the X12 is welcome, but the efficiency of a lot of PWM dimmed drivers is poor at the lowest settings, that is why I designed the single mode EcoDrive as I call it on the X16.

Ai this time I am hit by component shortages and was considering a run of X12s with a single mode same as the X16, to replace the lower range. However Toms post has alerted me to a possible loss of useful functionality.
 

Caver747

New member
Yes Pete, about the same size, but very simple one with a white light and red strobe that illuminates for a minimum of 100 hours, at least 10 times longer than the Petzl one with both functions and for about the quarter of it's price.

(Specs of Petzl here: https://www.petzl.com/INT/en/Sport/CLASSIC-headlamps/ePLUSLITE )

Tom, the scorpion x12 seems to run 22 hours on low setting.

 

Fishes

New member
I have no idea why anyone would need such a long burn time. If you are stuck then you only need a light if you were active.

Existing small headtorches with disposable AA batteries are a perfect backup light for me and easily last long enough to get me out.
 

royfellows

Well-known member
I bought one of these OLight torches
https://www.olightstore.uk/i1r-2-eos-kit.html?msclkid=13babc7993cf1f7592e6dd413bd87ff8&utm_source=bing&utm_medium=cpc&utm_campaign=Shopping&utm_term=4588880498408876&utm_content=All%20Products


My logic being that I will always have my keys with me.

Scorpion X12, the lowest settings are days not hours, I dont have the willpower to actually test one until the battery dies on the lowest setting.
 

Caver747

New member
Hey Fishes, thanks for your comment. I might need to think about other applications for this design. If you've got anything on your mind, please let me know.

Roy, thanks for the correction. That OLight seems really good for it' size.
 

sinker

New member
My Oldham burns for days and days on low setting. Like a candle but enough to live and get by.
Not suggesting that you should carry a lead acid battery around but it goes to show that, given modern battery tech, 1x candle power should last weeks rather than days.

 

tomferry

Well-known member
A very fast of the topic .

People I have been out with Roy love the simplicity of the x12 for taking photos just so your aware .

I believe the torch we was originally talking about could be good for a extreme emergency, especially if you could sow it into your collar to remove it in a emergency summit like have a zip their for it ?, for me personally though I no if the x12 dies and the wowtac a2s after this I shall be dead unless some one is in contact with me bringing food and drink .
 

royfellows

Well-known member
I have just tried the little Olight and it not work!
Basically, ! forget to charge it, and when did I buy it? About 18 months ago, and not charged.

Just tried it on my PCs USB and would not charge, put it into a mains adaptor USB and its charging.

So a long time burn survical light.
Well a single Sanyo 18650GA is 3500 mAh. So we can hit it for 35mA for 100 hours, or just over 4 days.
Driver inefficiency will knock the 35 mA back a bit, so would we be talking useful light?

Well definitely yes as far as seeing your hands is concerned, anything more, no. I ran an LED off my lab PSU through a fine scaled multi meter and only got 50% efficiency through the wiring impedance.
The lowest setting on the X12 is described as "moonlight mode" and really more a gimmick than a useful light. The next up is useful but probably only a couple of days, and this off a 3 18650 cell pack. This is probably as good as it gets.
 

tomferry

Well-known member
We did a test in a very large slate mine in Wales with the lowest settings , the moonlight mode it took a good while for the eyes to adjust to this but we was able to drink and eat I wouldn?t want to make my way out a mine with this setting but it?s a useful survival light , I am very glad I don?t have to flick past it though in my settings . The next mode up from moonlight you could walk out with that no issues .
 

royfellows

Well-known member
The super lamp the X16, and I have yet to sell a single one, (you do get honesty from this shop), has a blue power on light that will burn for weeks. This is by design, as a survical lamp. Its a Gallium Nitride emitter, possibly highest yet light output emitter, glows bright at 1 mA.

I am thinking the cheap Scorpion X could have its green power LED substituted with a green Gallium Nitride, trouble is it would start hiking the cost, and they are very tight on economic viability as it is. great value for customers though.

Anyway, sorry if anyone gets the hots for an X12 following Tom's comments, had to stop production for a while.
I have been on Farnell the morning after some stuff and its back order until May next year!
Fortunately found a substitute.
 

Caver747

New member
Tom, that's right, with an extreme long burn time the food and drink shortage would be the real issue much sooner. I'm thinking of a one-off, extremely small one, like you said. Or one that has a decent light output and still at least 48 hours burn time. And of course for a much lower price than a normal headlamp. 
 

royfellows

Well-known member
The little OLight is kaput I'm afraid, and don't think it was over discharge through non use/recharge. Maybe it come on in my pocket? Who knows.
For the price I buy another though, but this time take more care of it. Trouble with this stuff, if not checked regularly when you need it it wont work. Food for thought.

By the way, cant see any way to dismantle and possibly repair.
 

aricooperdavis

Moderator
I really rate the elite, it's IPX7 and is really comfy worn around the neck, which I think is a must for a backup light. I've not done a trip without it ever since I knocked my helmet off doing the Rowten sumps and found myself in a pitch black airbell :blink:

royfellows said:
The little OLight is kaput I'm afraid, and don't think it was over discharge through non use/recharge.

Is there an ideal battery chemistry for sitting around being very rarely used?
 

tomferry

Well-known member
https://www.amazon.co.uk/Headlamp-Headlight-Rechargeable-Waterproof-Headlamps/dp/B071HW5XQH

That is my back up torch i mentioned it?s survived many mining trips caving and the sump in Swildons with some waterfall climbs like gb etc .
 

Caver747

New member
royfellows said:
Is there an ideal battery chemistry for sitting around being very rarely used?



Out of the rechargeable ones (and commonly available) Lithium-ion or Lithium-polymer is still the best regarding self discharge rate.

In case you can use primary non-rechargeables, those shelf life is way longer. Lithium 1.5v and alkalines also good.

The absolute best is Lithium Thionyl Chloride, but as I know it's not rechargeable and got 3.6 volts.
 

royfellows

Well-known member
aricooperdavis said:
I really rate the elite, it's IPX7 and is really comfy worn around the neck, which I think is a must for a backup light. I've not done a trip without it ever since I knocked my helmet off doing the Rowten sumps and found myself in a pitch black airbell :blink:

royfellows said:
The little OLight is kaput I'm afraid, and don't think it was over discharge through non use/recharge.

Is there an ideal battery chemistry for sitting around being very rarely used?

Well, LiIon life time is rated upon the number of charge/discharge cycles, standing should not make any difference. However, some lights are on 'soft control' which meas they are on a stand by mode. I produce a lamp like this, but its controller is CMOS based which means it would take years to discharge the battery. Cant speak for Chinese stuff though.
Li Ion cells are ideally stored at 40%, in which case they should be OK for years. I have some early spec cells that are about 8 years old now, still showing factory voltage!

The OLight is 'hard switching' as screwing in in makes contact and turns it on, further rotation forces a prong inwards which which switches it to max. In view of this, I struggle to see whats gone wrong. They do come apart by the way, but just into the two halves. I cannot detect a voltage on the battery half, have not tried the LED.
 
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