Archive for October 18th, 2009
Must be something going around…
The outdoor thermometer over my desk (which also displays UTC so I don’t have to reset the mumble clock twice a year) started blinking. That’s the usual sign of a dead battery and, yup, when I opened it up, that “leakproof” Eveready was pretty far gone.
Surprisingly, at least to me, the cell hovered around 1.1 V open-circuit and 800 mV under the meter’s “battery test” load. Given the amount of corrosion, I thought it would be flat dead.
The corrosion had crawled out of the compartment along the negative terminal and coated the entire metal tab with bluish-green crystals. Some protracted dabbing with vinegar, rinsing with wet cotton swabs, and drying put things pretty much back in order.
I usually scrawl the date on each cell when I install it, but either I didn’t do that here or the corrosion ate the ink. All I know is that it’s been up there for quite a few years; look at the discoloration where it faces the sun through the window!
The thing was a surplus freebie to begin with and has long since been fully depreciated…