Battery chargers are a bit boring.
Today’s invention is a way to reinject a little extra drama.
Imagine a charger with no LED to indicate when the cells are charged.
Instead, there is a single small motor, fed from the mains and rotating the batteries slowly via a little gear.
When charging is complete, the batteries will have turn from showing eg a red outer side to a uniform green.
It would also be possible to have a message on the underside of the batteries, which would be revealed when they were ready.