This is a very simple little adapter - so simple, in fact, that I was surprised it didn't already exist.

Usually, for these Ryobi battery adapter you'll have to buy some ryobi component to make contact with the battery terminals - I needed something quick (to print and implement) using things I had on-hand - which were plenty of spade/fork terminals.

This little widget prints in 6 minutes and all you do is slip it over your battery and slide in your positive/negative wires that have been crimped with spade terminals (need to be <8mm wide). The tolerance is pretty tight - but I prefer a tight fit for the connection than something too loose.

This is obviously not intended for use where you'll need to move the battery around - this is for situations where the battery can stay stationary and you want to tap its voltage. In one of the images I've got it hooked up to a step-down puck so I could power another device with lower voltage requirements…