So [Travis] decided to upgrade it to make use of the ever-so-common, 18650 lithium-ion battery. Not looking to ... a few strips of cardboard from a case of beer — again, this is just making ...

In this case, [GreatScott!] wondered if it would be cheaper to make or buy a lithium-ion battery pack for his new ... he found he’d need thirteen 18650 cells in series but decided to double ...