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At Oxford, a Battery That's Lasted 175 Years -- So Far
sarahnaomi writes There sits, in the Clarendon Laboratory at Oxford University, a bell that has been ringing, nonstop, for at least 175 years. It's powered by a single battery that was installed in 1840. Researchers would love to know what the battery is made of, but they are afraid that opening the bell would ruin an experiment to see how long it will last. The bell's clapper oscillates back and forth constantly and quickly, meaning the Oxford Electric Bell, as it's called, has rung roughly 10 billion times, according to the university. It's made of what's called a "dry pile," which is one of the first electric batteries. Dry piles were invented by a guy named Giuseppe Zamboni (no relation to the ice resurfacing company) in the early 1800s. They use alternating discs of silver, zinc, sulfur, and other materials to generate low currents of electricity.
I assume the bell used to actually ring, and therefore pulled more than 2 nanoampere for a good while.
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Well, put a AA in a box and come back in 175 years, and try it out. Then we'll see how impressive that is.
That assumes the bell had been drawing the same current that entire time. The bell used to ring, meaning it was drawing much more current then.
All my liberal friends think I'm a conservative, all my conservative friends think I'm a liberal.
> 1 nanoamp is so tiny that it may be being recharged from the environment somehow.
At that rate it doesn't need any recharging. A continuous 1 nanoamp draw (it doesn't make sense to say it draws 1 nanoamp per oscillation because amperage is a rate not a quantity) would discharge a small 1 Amp-Hour battery over one billon hours, or 114,000 years. The fact that it hasn't discharged through interal leakage is pretty impressive though.
This is why a desert can go from 100F to near freezing in a matter of hours when the Earth rotates and the desert is radiating heat out into space.
Deserts are not vacuums. Deserts cool down at night mainly through air convection. High altitude air on the planet's night side is less buoyant, and is replaced by warmer air from lower altitudes, and this process repeats all the way down to the surface. Katabatic winds are often a result, which the California "sundowner" winds is a good example of.
Needless to say, that isn't much of a concern for the microclimates of spacecraft.
I don't think that's true. On a cloudy but windy night in the desert it doesn't get nearly as cold as on a clear windless night all other things being equal. In fact when I searched for "Desert nighttime cooling" here is the first thing that came up. It basically says under clear low humidity conditions at night radiative cooling is by far the the largest reason for cooling.
Probably not a whole lot more. Batteries have a reasonably constant voltage during most of their discharge cycle.
Even without the power a bayonet will do that to you