Battery ticks when charging.

[AlexThePalex]

OK, something strange, I have this old C12 NiCad with one battery that is at the end of its life with maybe 15% left, but lately I noticed it ticks one single time every 30 seconds or so when it is on the charger. Not when it is in use though.

Anybody ever experienced this before, and should I be worried it's going to explode in my face anytime soon? 

 

[Holmz]

I suppose it is safest to worry.

I would suspect that it most likely some thermal expansion induced creeping.

If you chuck it in the freezer then see if it creeps when thawing out on the table without charging?

 

[AlexThePalex]

Thermal expansion, that might be a possible explanation. The tick is very consistent and well timed though. I'll see what happens with the freezer. Thanks for the idea Holmz.

 

[Rip Van Winkle]

Some rechargeable batteries can produce gas when charging. Milwaukee had a recall at one point for some of their NiCd batteries because of a bad vent design that could be blocked from damage causing the batteries to explode.

Alternately, I suspect the ticking may be from the electronics in the charger, which is probably more likely.

 

[AlexThePalex]

Alternately, I suspect the ticking may be from the electronics in the charger, which is probably more likely.

No, I'm sure it is from the battery. The charger is the TRC3 from my T15 and there's no tick when I charge any of my four 15v LiIon batteries. It only happens with this one NiCd battery, which is obviously an oldy.