If the charger stays cool when charging, there is no problem putting it into the bag.
After reading instances where these type of failures have occurred I’m almost at the stage of thinking people using cheap chargers with *fire batteries deserve to have a scare! Now I know the possible outcome could be far more severe so of course I don’t actually wish that on anyone.
What is it going to take tho? A family burned to death in their house? That’s a very sobering thought and I really hope this makes people throw away any cheap cells, stick to the Panasonic/Sanyos etc and maintain safe practices.
It really is a shame as I believe good cells, well respected are very safe, the crap that people buy is going to lead to more and more restrictions 
I had some 14500 cells that were marked as protected but weren't.
This is kind of off topic here but all this talk about explosions and crap got me questioning my li on batteries.
I periodically discharge my batteries about once every 3 months to about 2.5v to check the capacity on the hobby charger. Most of my batteries are unprotected. Is that too low to discharge the cells? I didn't think it was but since there's so many of you experts here, I thought I'd ask. Maybe I should be taking them down to 2.8v like HKJ's tests or even as high as 3.0v?
It depends on the batteries, NCR18650A go down to 2.5 but the sanyo 2600 go down to 2.8. As a general rule discharge them to 3 unless you read that you can discharge them further.
It was mentioned earlier in the thread. Given the number of sellers that advertise protected cells and then send unprotected cells, it doesn’t surprise me. I don’t know of any like that.
Thanks. That makes sense. I sorta knew that but I've been draining them all to 2.5v due to laziness. I'll start taking them down to 3v going forward just to be safe.
You mean that they where without the protection PCB?
I got those figures i think from trooplewis, he was charging some stuff in the garage for a few days (forgot about it) and he did measure, believe it was the less branded cells. I’ll do a search, maybe i am wrong with some of the details….and i think it did not vent at all though the unloaded voltage was quite high @ ~ 4.3V when he pulled them and the cell looks messed up.
As mentioned it depends on the cells (we are using xxxfire cells and recycled cells here in BLF). We have so many factors involving the quality in manufacturing that it is mind boogling to say the least, it’s good to be careful.
Here’s a Li Po (ok so different chem but it’s definitely far from 12V) exploding at low 5V under charging load.
I’d definitely never put it as 10-12V as the ballpark, definitely not over here at budgetlightforums.
In an overcharged condition, the cell expands.
BTW one thing i have experienced also is that if you have a hobby charger, do take care. Some chargers do auto detection of cells and it just might charge a 1 x 18650 in 2S mode. It actually killed the PCB of my PAlight 18650, but that’s good coz the PCB cut and charger gave me a connection break error. If it’s unprotected, good luck bros! 
The charger are programmed with protection conditions, but nothing is foolproof unless yours is an extremely advanced charger (higher-end RC etc).
Here it is… there are a few others. (i’ll try to look for trooplewis thread) Ok so it’s Lipo and not LiCo cell, but just “FYI”.
Ok so this trooplewis’ thread. Seems like i got the figures mixed up. Holy cow 5.27V.
I know i read that ~ 4.3V version somewhere, youtube or what. (I’ll see if i can remember it, so far back…).
I saw one vid about LiFePO4 exploding too, but the abuse was immense.
No joke bros, as I have attached early of my X-ray with Ti plates + screws + a 11 thousand bucks bill, don’t leave anything to chance.
As I have learnt from my case, an accident = an accident, there is no way of putting anything concrete on that….no assumptions.
Yep, no protection. It was a recycled cell and the placed a sheet of aluminum over the negative end to make it look like it was protected. It was from dx.com.
Wow…just wow.
This is why I have the “SOP” that I shall test each and every new protected battery with a dead short test on the DMM and after that once in a while (be prepared to break the connection fast, it would save your DMM as well).
When i was still in the army, these SOPs are all written in a book called the TSR (Training Safety Regulations), which is compiled with the blood and lifes of soldiers.
On the same note, those bigger HIDs with > 1 mil cd are not toys and must be treated with proper respect. I was shot point blank by a 600-700k cd HID, at that range the beam isn’t even focussed and the bulb has cooled somewhat so not full power…… I was literally knocked off my feet + lost my balanced due to nauseousness, my eyes swelled after that for quite a few hours.
With those very big HIDs, treat the danger distance to anywhere less than 10 metres. Smaller 6” ones should be approx 5 metres. HIDs have some sort of long-wave UV (it makes your transition lens goes dark, some much more than others depending on the quartz envelope), not sure how is that focused along with visible light.
If you do short-arc, then that is quite a bit more.
I thought it would be an eye-opener to share these 2 laser incidents as well…. (warning, semi-gore pix inside)
Laser accidents are just that —-accidents—— something happens that is not expected ot anticipated nor subject to human intervention before it is too late.
>> Some people have strange imaginings that if there is a problem they will use their gogggles but do not want until then——when “then” happens it is too late— the damage has been done and so fast like you say faster than your blink reflex that under ordinary circumstances does a pretty good job of protecting your eyes —–1/4 second or less exposure can leave you completely blind you forever in the case of very powerful handhelds like yours.
People need to learn from the experiences of others that powerful lasers can be extremely dangerous unless handled with proper protection in place.
Here is the reason why Ultarfire 14500 gray battery explosion
The batteries explosion is not only because of the battery problems, but also because of the chargers. If the battery chargers have over charge protection and over discharge protection function, the the explosions will never happen.
You’d better buy the battery chargers come with over charge protection and over discharge protection function. Such as efest BIO chargers, Xtar chargers, HG chargers, I4、I2 chargers. Those chrgers all have protection cells function.
Bro, I do have that Trustfire charger, but the black version. That one does have overcharge protection cut-off….i have done it so many times with TF Flames 16340, Panasonic 2900/3100/Sanyo 2600 etc. It cuts a little high at 4.23x volts if you leave it there very long, that’s about it. I have never left it there for > 1 week after green, just feels funny to me. If it was a notebook (properly engineered systems) then that’s ok……
The LiCo blew at 4.43 volts under charging load here. 1 min 30 sec
A better solution - don’t use Ultrafire, go for good quality like Efest, Senybor, etc, there are a lot of good batteries out there.
Everybody sure they’re Ultrafires just because it says so on the label?
Ultrafire aren’t as terrible as all the fake $2 501A hosts on ebay make them out to be. 
What is a real UltraFire? In my test of 18650 batteries the ones that was supposed to be "real" UltraFire was the worst (They did not have the same capacity).
For example the lights that are manufactured by them are quite decent. Regardless, just because it says Ultrafire on the cover means practically nothing.