Ryobi one+ battery to makita drill adapter

Print parts: 

break apart the bodies, print top part upside-down
use built-in support body or use you own.

glue and screw together, open the drill, remove drill battery connector and place the whole 3dprinted assembly in place of the Makita battery.

Connect red to + black and yellow to -. I used wago 221 connectors.

Works just fine. Used in two old makita drills (2014 models: one 18V one 14V - which original batteries died long time ago)
 

Designed around: 
https://www.printables.com/model/137292
there were only stls published so I didn't want to reverse engineer it.