Fellow opens a $700 battery pack, finds a large sponge and a little $30 battery inside

The lithium battery pack for a Nagra 6 digital recorder costs $700. Markus Fuller opened one and found out it has a small battery in it (with 6 cells worth a total of $30), and a large sponge. It must be an awesome sponge! As he opens it, he gives an interesting and entertaining lesson on the history of lithium batteries.

Caveat emptor: Nagra sells a more expensive battery pack, which contains more batteries, so you won't get as much of the magical sponge if you buy it.

Fuller has a good video about capacitors, too:https://youtu.be/ZnG1423AZzU

[via]