LOL Teacher, I can handle a little sarcastic jab. But it does seem that I keep responding to the same notions over and over, from new folks that haven’t read previous posts. And if I disappear for a few days, or even a week, it’s not part of a plan. I just have a pretty busy life offline. I retired four years ago, and I’m still waiting for the “leisure” part to kick in.
However, this notion that we should never accommodate button tops because doing so encourages a bastard battery configuration that “shouldn’t even exist” (because the e-cig community doesn’t use them) is a new angle …
It’s my understanding that there is no lithium metal in lithium-ion cells. So, it shouldn’t react with water. Well, that’s my understanding, but I’ve never tried it.
Lithium primary cells do contain lithium metal, so I could see how those might react.
And responding quite well I might add funkychateau. If you are not an attorney… I think you could be. And probably a darn good one too…. … :+1:
Heck, I do not ever use buttontops unless a light absolutely requires them ; but your ‘arguments’ (reasons) even got me to thinking for a bit. Then I shook off your mesmerizing & got back on track.
Not my discussion so excuse the interruption, and I am not a chemist by trade, but I wouldn’t be taking that chance either. Elemental lithium is highly reactive, like you said, but many lithium-ions are too. My recollection from Chem1212, which granted was a long time ago, is that the lithium ions are going to react with the water pretty quickly, resulting in some sort of lithium oxide while releasing lots of hydrogen gas. This would be highly exothermic too, so lots of heat. Hydrogen gas + heat = bad news.
Besides that, I think the original premise here was that a bucket of water could be used to “put out” or otherwise contain a runaway li-ion cell, and that’s a faulty position from the outset. You won’t be stopping that internal lithium reaction with water. Its not going to stop until its out fuel/energy. So even if the water doesn’t make it worse (which I’m not convinced is true), its not really going to help either. You’ll still have a runaway li-ion cell on your hands…just now its wet.
So please, anyone who comes along reading this and decides to take some side cutters and a dremel to their stack of 18650s for any reason, do it outside. Away from everything you value. Because if something goes wrong you really only have one recourse — run away and let it burn itself out. A dead brown spot in the lawn is going to be best case here, I think.
Oops, I was thinking of removing just button tops. It’s a little more complicated removing protection circuits. Some circuits are on the positive end and some are on the negative/bottom end
For these types of cells you might need new wrappers and a heat gun/hair dryer.
You first have to carefully remove the outer wrapper. Be cautious around that metal strip running up the side.
Once I removed all of the extra circuitry and deburred any areas that were sticking out or sharp, I added a new wrapper to it.
Could be. But, if the battery is already on fire, it’s burning already.
No, I never meant to imply that. Lithium-ion cells contain their own oxidizer, so they don’t need oxygen to burn. Throwing it in a bucket of water hopefully contains the fire, and will help cool the cell. The latter being important if it’s just getting very very hot and hasn’t caught fire yet.
Anyway, don’t mess with cells if you’re not smart about it. But let’s not overstate the risk. The only way you’re going to cause a fire is if you puncture the cell. An accidental 1-second short isn’t going to do it.
Remember the times when the Airlines would not deliver Li-ion cells? Because of fires on planes? This was because of the vape folks ordering liquid’s for their vape unit and Li-ion cells together… when packaged poorly the containers of liquid got broken and the wet Li-ion cells combusted… in the cargo hold of the airplane. Wet Li-ion cells are just bad news. period.
Don’t teach people HOW to mangle a potentially lethal cell, teach them NOT to.
Or be sure your bank account is padded so when they screw up and sue you for the damages you can handle it.
Lawyering might be fun, but difficult to handle being the butt of so many bad jokes.
I used to be a professional nerd, running the Semiconductor Modeling Team and the Engineering Lab for a GaAs/GaN wafer fab and design facility in Dallas. But since 2015 I’m just another retired guy waiting for leisure time to kick in.
Another word of caution about attempting to modify li-ion cells: The power output of these cells is high enough to cause second-degree burns in the split second it takes to jerk one’s hand away.
Unfortunately, I know this from personal experience.
I think your right about the source.
I have quite a few from Li Ion Wholesale & all are very securely & nicely spot welded. They do it themselves, ‘in house’; and do it right.
I have several from China vendors & about half of them are spot welded. Most of those spotwelds are pretty crappy to…. especially compared to LiIon Wholesale.
But Jason, he’s asking specifically about the emitter choice in the FW3A, they say 1A or 7A so those are known choices as far as power binning goes.
HC, 7A is going to be dimmer and easier on the eyes almost regardless of power bin, there are only so many power bins available and to get a 1A that performed low enough to match a top tier 7A it would require a binning level not commonly available. So the 7A will be less, x 3. If the 1A is making 2800 on the triple then each emitter is making ~933 lumens, so if you were to see 20% less per emitter the total may be as low as ~2390 lumens as compared to the 2800 they list for the 1A. Sounds like a lot, still somewhat difficult to see in real world use. Side by side you could tell, but individually it would be difficult.
… :+1:
