Old batteries are old

For a while, it looked to me like my bicycle’s rear-light was “somewhat” dim. I supposed that the batteries might be getting low, but I was not sure.

So, given that I have a multimeter, and that the internets give ~20% decrease in voltage as reasonable limit for a non-recheargable battery that is not “dead”, I set to measure. The batteries are type N Battery (which were not as common as I hoped, at least not as common as either AA, AAA, D or C, all of which I could find at the nearby store, but not N).

Battery “marked” voltage: 1.5V. New batteries (after I replaced them): 1.451V (good enough). My old batteries… 1.041V.

Ouch! That’s ~30% decrease. No wonder I could stare in the light without problems :) With the new batteries in, it’s a bit painful to look directly into the small light.

In hindsight, 3 years of light (pun intended) use is more than reasonable.

So note to self: test batteries more often, at least at the beginning of the cycling season.