Drilling vent holes in all of my lights in case of battery vent
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Uuuuh...just to add a point here. The vented stuff is nothing to sneeze at. If I'm wrong then please correct me but anything that comes out of a flashlight at the 
moment is nothing you want to be near. Toxic.
I believe this should be pointed out.
(I seem to remember a Surefire nitrolon incan rechargeable kit with nicad (?) batteries had vent holes. Don't remember if it was for built up gasses or not.)
moment is nothing you want to be near. Toxic.I believe this should be pointed out.
(I seem to remember a Surefire nitrolon incan rechargeable kit with nicad (?) batteries had vent holes. Don't remember if it was for built up gasses or not.)
swan
Banned
Holedrillers-i have the answer, a BURST DISC as used in a super charger ie a thin plate in the side of the blower whichs ruptures if theres too much internal pressure,thus stopping an explosion. [i should take out a patent now!]-marty.
HarryN
Flashlight Enthusiast
I think of battery venting as two "sizes" of events:
a) Some normal breathing of cells that happens in a variety of chemistries
b) Fast venting, often with flames
For (a) I replaced the O rings in my lights with a special blue O ring material used by the military for fuel applications. It "seals" but is permeable to gases. I need to look it up, but you can buy it on - line. Just search for O rings using any engine and you will find it. The downside is that these O rings have almost no stretch at all and tear easily. I think they are about $ 1 each in flashlight sizes.
For (b) I thought about this quite hard, as at one time I considered to offer a custom light for sale and wanted to avoid problems. My solution was to design the O ring groove so that it would blow out (not well retained). Please note that this is an "incorrect" O ring design by normal standards and I just barely tighten it down - very little compression.
More or less, the side of the o ring is entirely visible on the light. It looks kind of cool being blue contrasted with the bare Al - but it's a personal taste thing.
The O ring life and installation is fine for me, but combined with the O ring in (a) it was questionable if people would accept it. I still break o rings on it if I am not careful. This and other things kept me from offering the light.
The descriptions of cells venting rapidly that I saw indicated that the top of the cell was more likely to vent than the back, possibly because that is where the vents usually are. If you agree with this logic, then the holes are only helpful if you put them near to where the cell top is located. A few layers of Al tape bonded together prior to applying it across the drilled hole can make for a reasonable pressure relief location. Some matching (or contrasting) color mylar tape can look nice and will rupture easily.
As far as hole size, I would think it has to be at least 1/2 the diameter of the cell to make a difference, otherwise it simply can't vent fast enough to matter.
Is this overkill ? - perhaps. In CA, we think a lot about liability.
If you do have one go off, get everyone out of the room because the fumes and residue are pretty bad. Clean up should be done with chemical gloves on.
At a personal level, with my entire family charging up batteries now, I decided to go back to NiMH cells, except for primary Li cell applications. Yes it does limit some choices, but reality is that not everyone in a family will accept multiple battery chemistry charging complexity.
a) Some normal breathing of cells that happens in a variety of chemistries
b) Fast venting, often with flames
For (a) I replaced the O rings in my lights with a special blue O ring material used by the military for fuel applications. It "seals" but is permeable to gases. I need to look it up, but you can buy it on - line. Just search for O rings using any engine and you will find it. The downside is that these O rings have almost no stretch at all and tear easily. I think they are about $ 1 each in flashlight sizes.
For (b) I thought about this quite hard, as at one time I considered to offer a custom light for sale and wanted to avoid problems. My solution was to design the O ring groove so that it would blow out (not well retained). Please note that this is an "incorrect" O ring design by normal standards and I just barely tighten it down - very little compression.
More or less, the side of the o ring is entirely visible on the light. It looks kind of cool being blue contrasted with the bare Al - but it's a personal taste thing.
The O ring life and installation is fine for me, but combined with the O ring in (a) it was questionable if people would accept it. I still break o rings on it if I am not careful. This and other things kept me from offering the light.
The descriptions of cells venting rapidly that I saw indicated that the top of the cell was more likely to vent than the back, possibly because that is where the vents usually are. If you agree with this logic, then the holes are only helpful if you put them near to where the cell top is located. A few layers of Al tape bonded together prior to applying it across the drilled hole can make for a reasonable pressure relief location. Some matching (or contrasting) color mylar tape can look nice and will rupture easily.
As far as hole size, I would think it has to be at least 1/2 the diameter of the cell to make a difference, otherwise it simply can't vent fast enough to matter.
Is this overkill ? - perhaps. In CA, we think a lot about liability.
If you do have one go off, get everyone out of the room because the fumes and residue are pretty bad. Clean up should be done with chemical gloves on.
At a personal level, with my entire family charging up batteries now, I decided to go back to NiMH cells, except for primary Li cell applications. Yes it does limit some choices, but reality is that not everyone in a family will accept multiple battery chemistry charging complexity.
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If the gas is so harmful, then maybe an expandable bulb type thing should be attached to the back. Something like this collapsible container. And a pressure activated valve could be built into it so it will vent to the air when fully expanded. But the simplest solution is a hole that you cap off only when you need the water resistance. Maybe it could be covered by some breathable material that turns color in the presence of the chemical that's vented, as a warning.
The argument about cellphones not being as waterproof, and therefore being safer than Li-ion powered flashlights, makes sense, but the exceptions may be the rugged cellphones that are waterproof. Mixing batteries isn't an issue with cellphones though.
The argument about cellphones not being as waterproof, and therefore being safer than Li-ion powered flashlights, makes sense, but the exceptions may be the rugged cellphones that are waterproof. Mixing batteries isn't an issue with cellphones though.
Jay R
Flashlight Enthusiast
I can't see any harm in it if that's what you want to do. You can get small rubber blanking gromets to push into the hole if it's on a flat side, not sure what you would do on a curved side. It may make the difference between one going pssssstttt rather than bang but the chances of it happening are so remote I'd also agree that it's a bit pointless. Most people have mobile phones, MP3 players and many have laptops all these with lithium cells so a venting is a pretty rare occasion when you look at the numbers. If you think about it, the chances of it happening to you are well into the high hundreds of thousands to one and if you make sure not to use old cells, mix different types etc.. it's probably into the high millions to one.
If you are going to worry that much about it then you should be worrying more about having kitchen knives in the house or not having a hand rail both sides of the stairs, both of which are more likely to cause your guests injury.
Did you consider that the greater chance of water getting inside the light via the hole may make the cell more likely to go bang ?
If you are going to worry that much about it then you should be worrying more about having kitchen knives in the house or not having a hand rail both sides of the stairs, both of which are more likely to cause your guests injury.
Did you consider that the greater chance of water getting inside the light via the hole may make the cell more likely to go bang ?
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Venting of flashlight case in case of blowout
Ok, the more I read the more I worry about my cheap ebay 2x18650 light. Has anyone added a vent hole in case of an over pressure event so it blows out in a controlled, more convenient direction? I was thinking of trying to drill a hole angled forward near the front of the light, in front of where my hand would be. I was then thinking of putting a dab of RTV in the hole to seal it. The RTV should blow right out if it over pressurizes.
Ok, the more I read the more I worry about my cheap ebay 2x18650 light. Has anyone added a vent hole in case of an over pressure event so it blows out in a controlled, more convenient direction? I was thinking of trying to drill a hole angled forward near the front of the light, in front of where my hand would be. I was then thinking of putting a dab of RTV in the hole to seal it. The RTV should blow right out if it over pressurizes.
bemymonkey
Newly Enlightened
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Re: Venting of flashlight case in case of blowout
Very interesting thread here... funnily enough, this was one of the first thoughts that went through my head when I started reading about the blow-out incidents.
To the "It's a dumb idea!" and "Oh yeah, go drill holes in your laptop and cell phone too!" proponents: Those devices aren't sealed metal tubes that turn a little lithium cell explosion/fire into the equivalent of a frag grenade.
@Cobra2411: What's RTV? I was considering just using a hot glue gun or regular old UHU (or any other softer glue that'll just pop out when the pressure rises)...
Very interesting thread here... funnily enough, this was one of the first thoughts that went through my head when I started reading about the blow-out incidents.
To the "It's a dumb idea!" and "Oh yeah, go drill holes in your laptop and cell phone too!" proponents: Those devices aren't sealed metal tubes that turn a little lithium cell explosion/fire into the equivalent of a frag grenade.
@Cobra2411: What's RTV? I was considering just using a hot glue gun or regular old UHU (or any other softer glue that'll just pop out when the pressure rises)...
Re: Venting of flashlight case in case of blowout
RTV Is a type of sealant. It's prety much universal because it solidifes at room temperature. When most people say RTV, they ar ereferring to a silicone sealant you can buy at places like Lowe's or Home Depot.
RTV Is a type of sealant. It's prety much universal because it solidifes at room temperature. When most people say RTV, they ar ereferring to a silicone sealant you can buy at places like Lowe's or Home Depot.
Kestrel
Flashaholic
I don't have a dog in this fight but FWIW here is the vent hole that SureFire put in my mint 7Z (which was a NiMH rechargeable light).
I was assured at the time by experienced forum members that this was a standard practice for the rechargeable SF's back then.
I was assured at the time by experienced forum members that this was a standard practice for the rechargeable SF's back then.
Kestrel
Flashaholic
I know, it's one of the smallest machined holes I've ever seen. Just thought I'd post since I had a pic handy.
ElectronGuru
Flashaholic
A14s have these as well, metal and G.
jasonck08
Flashlight Enthusiast
If individuals or surefire is going to put vent holes in the light, why not put a rubber plug in the vent hole so it still is water tight?
Also why not use a single quality 18650 or similar cell to reduce the chances of venting to almost zero?
Also why not use a single quality 18650 or similar cell to reduce the chances of venting to almost zero?
Felco
Newly Enlightened
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- Jun 2, 2007
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A small dab of silicone caulk would serve the same purpose.
Cellphones and other devices, in the event of a battery malfunction, would (relatively) harmlessly come apart.
A sealed tube like a flashlight is quite another matter.
A drilled vent hole will not stop a catastrophic battery malfunction blowing the end off the flashlight, but will considerably lessen the force (think of a bruise on your body versus a bloody wound).
Felco
Newly Enlightened
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Not sure what you're trying to say, TEEJ.
The caulk seal will blow out easily if there's an explosive event.
The caulk seal will blow out easily if there's an explosive event.
LOL
I'm trying to say that if the hole was to vent CORROSIVE GASES (IE: NOT explosive shock waves...), so that the internals of the light don't corrode....then plugging the holes meant to let the corrosive gases out will keep them in, where they can corrode the light.
Felco
Newly Enlightened
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Yeah, well I was talking about a catastrophic failure, not leaking corrosive gases. We seem to be on different pages.
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