NiMH Venting, How does this happen?

Pic 1


Pic 2



Forgive me, im relatively new at this. I just finished building my first Mag623, powered it up and ran for 4-5 minutes worked great. When i went to remove the batteries to check voltage the tube became suddenly very hot. I was able to get the tailcap off as smoke poured with some type of liquid. 6 batteries show no damage at all. The batteries in pic 1 show some leakage, but still have voltage at 1.312. The batteries in pic 2 are completely dead. The batteries are Elite 1700's 1 week old, all charged in the battery holder on a hyperion EOS0606i-AD @ 1.7c. Any help or information is greatly appreciated.
Thanks

Re: NiMH Venting?

siklops said:

Pic 1 http://img263.imageshack.us/img263/204/img0382be9.th.jpg
Pic 2 http://img263.imageshack.us/img263/2449/img0381de0.th.jpg

Forgive me, im relatively new at this. I just finished building my first Mag623, powered it up and ran for 4-5 minutes worked great. When i went to remove the batteries to check voltage the tube became suddenly very hot. I was able to get the tailcap off as smoke poured with some type of liquid. 6 batteries show no damage at all. The batteries in pic 1 show some leakage, but still have voltage at 1.312. The batteries in pic 2 are completely dead. The batteries are Elite 1700's 1 week old, all charged in the battery holder on a hyperion EOS0606i-AD @ 1.7c. Any help or information is greatly appreciated.
Thanks

Click to expand...

Six damaged batteries in the photos, and 6 more that are undamaged, equals a total of 12 AA batteries... were these in four 3AA-to-1D adapters? and two of the triplets got messed up, while the other two triplets are undamaged?

Re: NiMH Venting?

I hope you did not breathe the smoke in

Re: NiMH Venting?

Aluminous said:

Six damaged batteries in the photos, and 6 more that are undamaged, equals a total of 12 AA batteries... were these in four 3AA-to-1D adapters? and two of the triplets got messed up, while the other two triplets are undamaged?

Click to expand...

All 12 batteries were in a 12AA to 3D series adapter. I had my charger set to charge them at 14.4v, they came off the charger at 17.1v. I let them rest for a bit until they were at 16.7v

TOOCOOL said:

I hope you did not breathe the smoke in

Click to expand...

I tried not to, i left the area as fast as i could. What are the health hazards?

Re: NiMH Venting?

siklops said:

All 12 batteries were in a 12AA to 3D series adapter. I had my charger set to charge them at 14.4v, they came off the charger at 17.1v. I let them rest for a bit until they were at 16.7v



I tried not to, i left the area as fast as i could. What are the health hazards?

Click to expand...

RayoVac MSDS http://gpsbattery.com/NiMHBatteryMSDS.asp?id=
Seabird MSDS http://www.seabird.com/pdf_documents/msds_sheets/Saft-NiMH.pdf
Panasonic MSDS http://www.master-instruments.com.au/Special Pages/Battery Information/MSDS/Panasonic NiMH MSDS.pdf
Panasonic claims their batteries are listed as "articles" thereby exempting them from MSDS requirements.
Energizer MSDS (better MSDS)http://data.energizer.com/PDFs/nickelmetalhydride_psds.pdf

Not familiar with this hazard issue, just quickly copied a few MSDS sheets.

Ok, i have the health hazards taken care of. What caused the batteries to short out? Defective batteries, battery holder, or the battery tube itself? The batteries that are completely dead were not one right after another in series. I dont know if i should buy more batteries and try it again, this was the first time they were inserted into the battery tube. I just dont want another

Hello Siklops,

Welcome to CPF.

From the damage, it looks like your cells shorted out. I would suggest you take a good look at your battery holder to make sure that there is nothing that is out of place. The next possibility is that the shrink wrap was compromised on those cells from a tight fitting battery pack.

If all the cells were new, get some replacement cells for those that were damaged and put them through a few cycles to get them to about the same place as the other cells. If the cells are well used, get a whole new set.

Good luck.

Tom

SilverFox said:

Hello Siklops,

Welcome to CPF.

From the damage, it looks like your cells shorted out. I would suggest you take a good look at your battery holder to make sure that there is nothing that is out of place. The next possibility is that the shrink wrap was compromised on those cells from a tight fitting battery pack.

If all the cells were new, get some replacement cells for those that were damaged and put them through a few cycles to get them to about the same place as the other cells. If the cells are well used, get a whole new set.

Good luck.

Tom

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Silverfox, thank you for the response. I had to remove the shrinkwrap on 2 cells that were at the bottom end of the battery holder as they wouldnt slide into place without deforming the battery holder. You think they shorted out there and caused a chain reaction? Everything on this light was new, i was using AW's incan driver i think some of the electrolyte contacted it. Not sure how to test it though. Ill buy some more cells and cycle them.

Hello Siklops,

If things are that tight, I would suggest that you bore the light out a little. I am not sure how that holder is set up, but it is entirely possible that the lack of insulation contributed to the problem.

Tom

SF beat me too it.

SilverFox said:

Hello Siklops,

If things are that tight, I would suggest that you bore the light out a little. I am not sure how that holder is set up, but it is entirely possible that the lack of insulation contributed to the problem.

Tom

Click to expand...

The battery holder slides in and out just fine. When i try to insert a battery into the holder itself it was too tight. I just figured i could remove the shrinkwrap and be ok, guess not. Ill see if i can remove a little more material from the battery holder.