Scary little batery pops

I was just sitting at the computer earlier with 3 batteries on the chargers next to me:

1 AW IMR 18650 in my Nitecore i4.
2 Duraloops NiMh (white top) on a discharge cycle in my Titanium rapid charger (the one that takes 4XD sized batteries)


About a half hour after I put the batteries on the chargers, I heard very small regular pops, like tiny tiny battery farts. I didn't take a chance, just took all 3 batteries off the charger and walked to the other side of the desk where nothing would blow in my face. The pops kept coming but slower. I took the 18650 and put it outside on the balcony and walked back. Still popping... I took the Duracell with the lower charge capacity and put it outside. I still could hear the popping! I put the last battery outside, took back the other Duracell and closed the door for a good 5 minutes. No popping could be heard from any source indoors at this point.

When I opened the door, I took back my 18650 and took the Duracell in my hand... it still felt warm while the other batteries where cool! It stayed there for another 10 minutes until it felt cool. The 18650 is charging right in front of me (almost full and still feels cool), the 2 Duraloops are in a ziploc in a metal can on top of the washer right in front of the fire alarm. Not like I actually want to be paranoid, but I'm probably tossing those out to be safe since I definitely have more NiMh's than I need.

I'm also thinking the popping could have been coming from the charger, but there has been absolutely no smell associated with this event... I will be testing my charger with other batteries in the same position, but I was wondering if anyone has ever had a similar experience?






Background on the batteries:

The AW 18650 battery came with a device (E-cig) I bought from a guy I know and can trust around February and tested 0V at the time. The guy had forgotten it in the e-cig I bought from him for about 6 months time, which means the battery was less than a year old at the time of the purchase. I put it in the charger just long enough to reset the protection and it showed 2.8v, so I decided to charge it while checking it closely. Worked just fine ever since.

The 2 Duraloops have been somewhat neglected in the sense that they have been spares for my Zebra H51Fc, but did not get much use in the last 3-6 months. They just sat in the box with a full charge most of the time, but got sporadic use a few times a year since I bought them. I have cycled them a few times in the last weeks as they had a low charge level even after a full charge and one of them was still not lasting very long while the other was just fine. Those batteries are about 2.5 years old. I'm currently using 1 other Duraloop that came out of the same package with no problem. I'll be taking the 4th one out and closely monitor it starting tomorrow.

NOTE: I have had very good experience in the past with "Duraloops" and Titanium chargers and it seems that everyone else on here also has...

Interesting, thanks for reporting that.

I have never experienced NiMH cells (or chargers) do this, but there's quite a few situations where NimH cells can turn into a ticking time bomb, just google "can nimh cells be dangerous". SilverFox mentioned in another post about NiMH explosions. But usually that would occur if you overcharged the cells too much. What was the current rate you were using on those Duracells? Not typical that they need a break in but maybe they were dropped or something that would cause the battery to pop like that.. have you tried using other batteries with the charger(s) that were in operation?

I am very curious about this thread. I had what I believe to be the same Titanium charger. The charger would literally blow your cells if you did not unplug it once the cells charged its like the charger wouldnt turn off once charge had been attained it always still fed charged cells a trickle charge. It was an expensive charger and quite honestly flat out dangerous I ended up giving it away. It just charged to hard to fast cells would come off blazing hot. My money is on the problem being the Titanium charger itself. God forbid any cell thats old or has been cycled many times end up on it had I not monitered the cells personally all the time the darn thing would have burned my house down

Interesting. Sounds as if my battery had small hydrogen farts. I don't think I'll push it just to see if it will leak electrolytes, though, but that was a very educative post.

I doubt I was overcharging the cells; the Titanium chargers are very safe, but that cell had diminished capacity due to the fact that I did not use it often enough in the last 24 months and it was its second charge (with a full discharge in between) in about 2 days.

I do not have any cells to charge at the moment, so I'll wait for a real test occasion, likely this weekend. I did cycle these batteries in charge/discharge cycles fairly often to keep their capacity up, but I have given other batteries the same treatment at the exact same time, some due for retirement, some still in great condition.

The titanium Md-3000 delivers 1700 mA for NiMh AA size and up. I have mostly used my MD-1600L, which delivers 400mA. Perhaps that cell just isn't performing anymore and nearly completely crystallized.

As for the 18650, it is still performing admirably and has been charged at least once since and is charging at this moment.

I indeed had the same Titanium charger. I also at the time was flush with Duraloops and it was with those cells and some D size Tenergy NiMHs that the charger would "cook" to the point of being to hot to touch. I guess I got a bad copy of the Titanium. Oddly my good old cheap Nitecore d4 has been rolling right along for over a year with no issues. Just ordered what seems to be the very nice multi chem Xtar VC4 as the Nitecore is getting kinda beat up. I also have the 8 bay Maha C808 that does an amazing job for all my NiMHs.

CelticCross74 said:

I indeed had the same Titanium charger. I also at the time was flush with Duraloops and it was with those cells and some D size Tenergy NiMHs that the charger would "cook" to the point of being to hot to touch. I guess I got a bad copy of the Titanium. Oddly my good old cheap Nitecore d4 has been rolling right along for over a year with no issues. Just ordered what seems to be the very nice multi chem Xtar VC4 as the Nitecore is getting kinda beat up. I also have the 8 bay Maha C808 that does an amazing job for all my NiMHs.

Click to expand...

Extremely interesting remark about the bad copy. I got mine locally at an international battery distributor, but I also noticed the highest quality li-ion cells they have are Tenergy and I do get less than average runtime on my TK-70 (not by much and I do admit I'm not using it very regularly though, but charger and batteries came from them). I somewhat doubt they would buy ripoffs unless they are not aware of it.

I just ran another AA (Rayovac) in the Md-3000 and started hearing what sounded like a regular beep and some squeaking. Both sounds were just barely audible, but the battery was a little warmer than comfortable to handle. It seems it might be delivering more amps than the batteries like. I will try that battery on my MD-1600L once it cools off for a while. I never had really hot batteries coming from the 1600 and it. 1 battery is not too surprising. 2 is weird, 3 is very suspect. I still can foresee a Maha from a big seller in my not-very-distant future.