One day, while working at the desk, I heard a pop, a loud bang, and something ricocheting in my room. When I had time to process what happened, I figured something solid had hit the blades of my ceiling fan. I was lucky the piece of whatever it was didn’t hit me.

I climbed up to the ceiling fan and found one of the plastic blades is chipped. Common sense suggests that something dropped from above the ceiling fan and hit it while it was spinning, but there was nothing above the fan, only the ceiling.

The clip was at the very outer circumference of the blade, so it could not have been a loose nut or bolt. The ceiling is made of wood, there was no chance of a piece of it chipping off and hitting the fan.

I could not find the projectile so I could not figure out what had happened.

A few days later, I checked on my supply of batteries on the shelf and found that one of the LR44 is missing the negative anode. I have never seen that before, a button cell with a missing negative cap. And then I realised, this could be it.

For some reason, the anode of this off-brand button cell battery I got from MR. DIY, popped, hit the ceiling fan and was met with such force that it ricochets somewhere in my room. MR. DIY was the only place I could find LR44 batteries at the time. Maybe cheap batteries are not worth the risk.