18650 battery holder (2 x 4 pairs)

This thing was made with Tinkercad: https://www.tinkercad.com/things/kjkwal8UzEc

You need two of these (top and bottom) to sandwich eight pairs of 18650 batteries.Then you can slot them together to create larger battery packs.

I've been re-using recycled laptop batteries for an electric lawn mower, electric go-cart and electric drill. Next step is a DYI "Tesla style" power wall with several thousand 18650 cells.