News Report of AA NiMH explosion during charging

TorchBoy

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65535

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A proper metal can cell will have vents which keep the cell from exploding.

I've personally seen high capacity Sub-C NiMH cells vent from dead shorting a charge 6 cell pack. The cells instantly heated up to hundreds of degrees, melting the solder on the battery bars, and venting the cells. 2-3 foot streams of venting gas from the buttons on the cells, but no explosion, no fire.

These are simply poorly designed cells. Cells with proper vents will cause little damage, a reliable charger isn't able to burn a battery like that.
 

just_now

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Don't remember the brand of the charger but the batteries are from Lenner (purchased charger and batteries at my local Fry's)

Will only now use eneloops. Live and learn...

Just glad it wasn't my RC Lipo 5s 5000 mah that this happen to. For this, I use a Hyperion 610net charger for. I store these batteries in a nice steel box and only charge these outside. I follow all safety steps when it comes to the larger batteries, but did not imagine that AA 1.2 volts were so dangerous!

 

alfreddajero

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I dont think it could be the battery, too me the charger might be the culprit.....how does the charger work with other sets of batteries.
 

J_C

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I dont think it could be the battery, too me the charger might be the culprit.....how does the charger work with other sets of batteries.

Has to be the battery. I can hook a AA NiMH directly up to my car battery at 13.8V and leave it, expecting nothing other than it will vent. Only on a defective NiMH cell will internal pressure build up to the point of rupture instead of the vent opening.

I'm not suggesting the charger isn't possibly to blame for overcharging, but at most that ruins a cell, a couple dollars lost not an explosion.
 

bstrickler

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I've personally seen high capacity Sub-C NiMH cells vent from dead shorting a charge 6 cell pack. The cells instantly heated up to hundreds of degrees, melting the solder on the battery bars, and venting the cells. 2-3 foot streams of venting gas from the buttons on the cells, but no explosion, no fire.

I almost had that happen with a 10C rated Sub-C Tenergy cell. Somehow, the shrinkwrap under the solder tab wore away, and I didn't see that. When I folded the tab over, the solder tab got RED hot, and the cell heated up instantly. Rather than risking it exploding, I risked my thumb, and flipped the tab back over. Ended up burning about a 1/8" deep valley into my thumb, because the tab was so hot. Now I know, DOUBLE CHECK YOUR CELLS BEFORE YOU USE THEM! If I hadn't been so quick and lucky, the cell would probably have vented into my face, blinding me. That cell now is in the dump (I cut the tab off, and discharged the cell as fully as I could, to prevent an explosion)

Now you know, lak, to keep an eye on all cells you are charging, and don't leave them unattended. I personally keep my cells right next to me, in case my charger should fail for some reason, so I can grab the charger, and throw it out back before anything worse happens.

~Brian
 

GRB3

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I'm beginning to wonder if I am in over my head. I have just gotten a PILA charger and several of their batteries. All my flashlights are off the shelf Fenix or Surefire. I have a bunch of Maglites and stuff like that including a 15 year, or older, rechargeable ML that stays on the charger virtually all the time.

With the newer high powered batteries do I have to watch them charge? I thought, from what I've read, that the PILA was pretty much 'put the batteries in it and forget it'. Am I wrong? Should I stay with non-rechargeable batteries? Should I buy a flashlight that will take the bigger PILA batteries or go back to the shallow end of the pool? Can I safely charge other quality batteries in the PILA? C!an I mix the 123s and the larger 18650s (?)?

I've got a lot to learn.:ohgeez:
 

J_C

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They're all pretty much put the batteries in and forget them... NiMH explosions are only from defective cells and they aren't firey explosions like with Li-Ion.

With dumb chargers the worst you should expect is overcharge damaging a cell, loss of capacity/rise in impedance, or of course leakage so I wouldn't put the charger on your best antique wood table but otherwise most of us have things that charge NiMH all the time like cordless phones.

It is possible you get a defective battery, or a defective charger, but it is similarly possible you buy a defective alarm clock, TV, light bulb, etc, and those aren't considered things to constantly watch. It's all about the failure mode, Li-Ion failure is particularly bad but that NiMH batteries are batteries, is for the sake of concern, only a coincidence.
 

GRB3

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Thanks. Shouldn't I get a battery tester and if so what kind? I've got a Frys not far away.
 

Mr Happy

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I'm beginning to wonder if I am in over my head. I have just gotten a PILA charger and several of their batteries. All my flashlights are off the shelf Fenix or Surefire. I have a bunch of Maglites and stuff like that including a 15 year, or older, rechargeable ML that stays on the charger virtually all the time.

With the newer high powered batteries do I have to watch them charge? I thought, from what I've read, that the PILA was pretty much 'put the batteries in it and forget it'. Am I wrong? Should I stay with non-rechargeable batteries? Should I buy a flashlight that will take the bigger PILA batteries or go back to the shallow end of the pool? Can I safely charge other quality batteries in the PILA? C!an I mix the 123s and the larger 18650s (?)?

I've got a lot to learn.:ohgeez:

They're all pretty much put the batteries in and forget them... NiMH explosions are only from defective cells and they aren't firey explosions like with Li-Ion.

With dumb chargers the worst you should expect is overcharge damaging a cell, loss of capacity/rise in impedance, or of course leakage so I wouldn't put the charger on your best antique wood table but otherwise most of us have things that charge NiMH all the time like cordless phones.

It is possible you get a defective battery, or a defective charger, but it is similarly possible you buy a defective alarm clock, TV, light bulb, etc, and those aren't considered things to constantly watch. It's all about the failure mode, Li-Ion failure is particularly bad but that NiMH batteries are batteries, is for the sake of concern, only a coincidence.

I'm very confused here. GRB3 wrote about a PILA charger and batteries (lithium ion system) in a thread about NiMH. But GRB3 does not describe owning any PILA flashlights. Surefire lights do not in general take rechargeable batteries (they take primary CR123A cells), Maglites do not take lithium ion rechargeables, and Fenix lights are varied but mostly take NiMH or primary CR123A cells. So the main question to GRB3 is: what lights to you plan to use your PILA batteries in?

Then J_C wrote a response all about NiMH batteries, but GRB3 asked about PILA lithium ion cells. On the face of it there is no relevance between the answer and the question.

Unless GRB3 can give more information to clarify the question, I think that yes, you may be in way over your head.
 

J_C

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Then J_C wrote a response all about NiMH batteries, but GRB3 asked about PILA lithium ion cells. On the face of it there is no relevance between the answer and the question.

Thank you for pointing that out. Yes I had assumed in a topic about NiMH, that unless someone specified another battery type that they were referring to NiMH.
 

GRB3

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No doubt I'm in over my head. I realize the PILA batteries will not fit in my Surefire or Fenix. I plan to order a PILA flashlight unless I run across something better that will take the larger battery. I'm here to enjoy the hobby and learn. I'm just trying to avoid taking off a limb in the in the process.
 

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