Need some advise because I don’t have experience with this scenario: What can happen if a flashlight with Li-ion is accidentally left on for days unattended?
Today I left my Skilhunt h02 headlamp at a worksite, turned on inside a machine. It was either on medium or high and has a protected cell.
I don’t think this light has Low-voltage protection where the light will shut itself off. It does have the low voltage warning where the light blinks when the battery is low.
Recently I accidentally left this light on and stuck to the frame underneath my vehicle overnight (it has the tail magnet) then drove over 100 miles the next day, I remembered where it was and to my surprise it was still there stuck to the frame and it was still on!
So if I don’t go back to where it is for several days or a week will it just run down the battery until it dies, or could it explode or catch fire etc.?
I doubt the light will heat up enough for the cell to vent. My guess is that the protected cell would trip and shut off the light without problems. An unprotected cell may pose a danger when recharging.
If you asking about your headlight I’d say no worries. If it’s a general question I’d say it depends on what light it is and where it is. My BMF light went on in my backpack on highest mode. It almost started a fire, quite a bit of smoke was coming out when I noticed (backpack was on my back). I’ve since then programed in a safety lock feature.
Thinking of this, I was wondering if there is an (easily) available material that you van cut in to disks to add to the battery tube to prevent overheating when you transport your flashlight? Would be something I consider using.
Are you not using a protected cell in the light? I did runtime tests for my review last year, and I don’t think the light has low voltage protection, because it would just get dimmer and dimmer. I used protected cells for my runtime tests, and just turned the light on and let it run till it died.
In my experience, the protection circuit usually doesn’t kick in until the voltage is already too low when it’s in a trickle-drain situation, such as moonlight mode or parasitic drain from a soft switch. This is why I don’t do low-mode runtime tests on my Li-Ion lights, and I’m pretty careful about storing lights with soft switches by unscrewing the threads a few turns to break the connection.
I do this in the interest of flashlight science. Believe it or not, I have seen many many incorrect features in flashlight manuals. Reverse polarity protection (spark), weight, length, lumens, etc. I feel my runtime tests should show a user what the light does when running this way. So if it runs for many many hours in a low mode without shutting off, lets say it’s a light I’d not like to leave running. There have been times where a light would just not shut off, after starting out in turbo. I usually reference that in my reviews… and I have turned a light off and cut the runtime test off out of fear of safety. I do this only when I have a protected cell, and cut the tests short much earlier if it’s an unprotected cell.
But yes, I wouldn’t say it’s entirely safe. I just use quality protected cells and hedge my bets, when doing runtime tests.
Yes protected. An XTAR 2600mAh. XTAR does not list the specs of the over-discharge protection circuit but I assume it cuts off at (or near) 2.5v
The runtime tests in your video you stop the tests before it died (before the light cuts completely off), and the Soshine you use is an unprotected battery? Also i’m curious, at the end of the tests has the battery run down to 2.5v or less? (Excellent video review BTW)
Sounds like you both agree there is a possibility something bad could happen. It’s been about 40 hours now since I turned it on, so far so good, no news is good news. Thanks for posting.