You can make your own lithium-ion batteries if you have a source ... [Bill Porter] put together a quick tutorial where he makes a 14.4V 2.2 AH battery for about $10. He picked up a set of cable ...

The vest is powered by a 7.4V lithium-ion battery that lasts up to 15 hours, and it’s recharged with a USB type-C cable. Note that this fleece vest is not waterproof, so you’ll need a water ...