As mentioned in some other topic, I picked up a Ryobi Fuel Gauge a week or so ago. It supplies a visual representation of the state of charge of any 18 VDC Ryobi One+ battery. It's mostly useful with the NiCad packs as the LIons have the built in indicator. The Fuel Gauge does offer one extra state of charge indicator.
This shows the battery at approx 3/4 charge.
(https://i133.photobucket.com/albums/q75/djmillerbucket/oddsnends2/P1000426.jpg)
I find it nice as it keeps me from throwing a NiCad onto the charger when it doesn't really need it (& thereby shortening its life).
The unit is simply slipped onto the battery; it runs thru a self check and then displays the state of charge. There's a warning not to leave the unit on the battery as it will discharge a full battery in about 48 hours. d*
Thanks Don. I have several Ryobi tools, and 4 batteries.
Will look for one next time in L's or HD.
Steve