I’m always on the lookout for cheap power. So I was intrigued by these phone battery packs in the pound shop in Hull. It turns out that they are actually quite usable if you need to power small electronic devices. I’m pretty sure that the advertised capacity of 1200 mAh is more than a bit optimistic, but I do know that a fully charged battery powered my “full fat” air quality sensor for well over two hours, which is good for demonstrations and the odd bit of remote sampling.
Apparently there are some that cost twice as much (that’s two pounds) which last around twice as long.