Rechargeable AA burned up

Just a little while ago I needed to change the batteries in my camera. I had 4 that I had recharged a few days ago, so I went to my workbench and pulled the 4 out of the recharger and set them on my desk. I got my camera and then reached for the 4 batteries. Instantly I felt a sharp pain in my hand as if I were stabbed with a pin or needle. I dropped the batteries back on the desk and looked at my hand. No blood or cut. So I started picking the batteries back up one by one to see if there was anything wierd about them. When I got to the third one I found it was VERY hot. I dropped it again. Within seconds it started cracklying and popping like a log on a hot campfire. Smoke and couple of tiny sparks came from right around the little nipple (positive end). I knocked it on floor so it wouldn't burn my paper deskpad. Then I kicked it out of the room, down the hallway to the bathroom. (first place without carpet) The battery, smoking a little less now, started to melt the bathroom floor. So I grabbed a small hand towel, wet it and picked up the battery and dropped it on the front porch.

End of story........

The battery is a 2250mAh Nickel Metal Hydride AA. The charger is a universal charger able to handle all types of batteries (and set to the right type) and all sizes of batteries. It shuts off when the batteries are done. (the light goes out)

So what happened?

It blew up sorry bro I couldnt resist but it could have had a crack in it and it just went

https://data.energizer.com/PDFs/nickelmetalhydride_psds.pdf

It had a short. They can cause fires.

What brand was it?

Was it a "Happy Fun Battery"?

Originally posted by Rocketmaniac
Just a little while ago I needed to change the batteries in my camera. I had 4 that I had recharged a few days ago, so I went to my workbench and pulled the 4 out of the recharger and set them on my desk. I got my camera and then reached for the 4 batteries. Instantly I felt a sharp pain in my hand as if I were stabbed with a pin or needle. I dropped the batteries back on the desk and looked at my hand. No blood or cut. So I started picking the batteries back up one by one to see if there was anything wierd about them. When I got to the third one I found it was VERY hot. I dropped it again. Within seconds it started cracklying and popping like a log on a hot campfire. Smoke and couple of tiny sparks came from right around the little nipple (positive end). I knocked it on floor so it wouldn't burn my paper deskpad. Then I kicked it out of the room, down the hallway to the bathroom. (first place without carpet) The battery, smoking a little less now, started to melt the bathroom floor. So I grabbed a small hand towel, wet it and picked up the battery and dropped it on the front porch.

End of story........

The battery is a 2250mAh Nickel Metal Hydride AA. The charger is a universal charger able to handle all types of batteries (and set to the right type) and all sizes of batteries. It shuts off when the batteries are done. (the light goes out)

So what happened?

Click to expand...

Yikes! I don't like data sheets that use the words "spontaneous combustion"

Originally posted by shreadvector
What brand was it?

Was it a "Happy Fun Battery"?

Click to expand...

It was a Powerizer brand. Subtitle is "Professional for digital camera"


Is Happy Fun Battery is brand?

I've had this happen to be before as well.

I was using my nitro RC car and heard a bang. first thing that came to mind was that I did a rod(no good) anyway drove the car back to me and it was fine.?

Took a couple of secs for me to think about it,but I took the cover off my remote control and one of the batterys had foaming acid coming out of it.So I took it out(fliked it out on to the ground)and thats where it stayed.

From memory it was on th side or the negative end.

So it does happen from time to time.

A reference to "Happy Fun Ball" which has the following warning label:

https://www.happyfunball.com/hfb.html

https://snltranscripts.jt.org/90/90mhappyfunball.phtml

Originally posted by Rocketmaniac
It was a Powerizer brand. Subtitle is "Professional for digital camera"


Is Happy Fun Battery is brand?

Click to expand...

.

it could be worse:

https://soundwavs.trekkieguy.com/1/13/overload.wav

You didn't mention the battery history or charge rate of your charger. Were all the batteries at the same state of charge, or were they sitting around discharged for a period of time, or were they near the end of their useful life?

NiMH batteries have much higher capacity than the equivalent size NiCAD, however they can't be charged exactly the the same way.

Both batteries can be fast charged to ~ 90% of their capacity, but then the rated has to be reduced or they will badly overheat. Prolonged high current overcharging generates a lot of heat, kills the battery, and can start a fire. A good charger monitors the charge process and adjusts accordingly, however if the process is interrupted, bad things can happen. Also if the battery is flat (below ~0.8 V), you can have problems charging it in some types of chargers. Batteries that low need to be trickle charged to get to get above 0.9 Volts before you put them in a fast charger. If one battery is much more discharged than the rest, a problem could arise.

NiMH batteries also don't want to be trickle charged for long periods after they are fully charged.

Here's an interesting discussion of a similar problem observed with this battery.

https://www.candlepowerforums.com/vb/showthread.php?t=114466

https://candlepowerforums.com/vb/showthread.php?t=79302&page=1&pp=30

It's hard to say exactly what happened, but it shows that you need to carefully watch the batteries when you recharge them.

Bob

Originally posted by Rock_It
What you had there is called a closed short, and whenever a battery is hot get away! They will get warm sometimes and that's ok, but hot can cause venting (which this one did) and on some types of batteries can actually cause explosions. Yes, I said explosion...as powerful as a 12 guage shotgun shell.

Click to expand...

Now the ATF will have to start regulating betteries!

.

Ok guys.... please don't make this thread go down the wrong path.

Originally posted by bobkrech
You didn't mention the battery history or charge rate of your charger. Were all the batteries at the same state of charge, or were they sitting around discharged for a period of time, or were they near the end of their useful life?

Click to expand...

Good questions....

The battery was fairly new. It might have been recharged 6-8 times.

Rate of charge. I don't know exactly.

All 4 batteries were totally charged, but had not been sitting around for too long.




I don't know if my charger totally "turns off" after the batteries are charged (the charging light goes out) or if it goes into trickle mode.

Can batteries get too much trickle charge?

Randy

Yes, you can overcharge a NiMH battery on a trickle charge. A lot depends on the exact charging sequence, and trickle rate.

Some chargers put in a lot of juice initially, and after the battery gets to a given voltage/temperature, they go in to a second charging mode (either constant voltage or constant current) for a given time and or voltage, and then go to a trickle charge and/or shut off.

If your batteries are almost fully charged, or if you unplug and replug in the charger, you can fake out the electronics and overcharge the batteries with some types of chargers.

The best chargers have a lot of protection built-in. Of the discount sources, this one from https://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=2607 looks really nice. It has 8 independent charging channels, has microprocessor controlled - negative delta V cut-off function, and individual cell temperature sensors. It's not a fast charger, so it will take 10-12 hours to fully charge 2 - 2.5 AH cells, but it won't likely fry them either, and it runs on 12 volts or any AC voltage. It also checks for bad cells.

You might have been unlucky to have received a bad cell, or the charger may have screwed up. Hard to say. NiMH batteries are a commodity item, and there is a lot of second sourcing, even by the big boys, so brand name don't necessarily mean much. If you're not in the business, you simply don't know who made them.

Bob