Hi all, what's the best percentage to keep the batteries in the best possible condition for long periods of inactivity?

With my Dji mini 3 pro drone, it usually best to charge it 100% and stored in the battery pack. Batteries there are designed to discharge automatically for them to stay in health. When they are close to completely discharge, i charge it back to 100% again.

What about Dji Action 3 camera?

store in mug of boiling water, with bleach inside to keep clean. (jkjk)

Lithium batteries are generally best stored at between 50-80% charge.  Storing at full charge will degrade the cells over time.  Storing too low risks the cells becoming over-discharged, which is also bad for the cells (and depending on internal protections, may be irrecoverable).

Hello there Astroita87. Good day and thank you for reaching out. For additional reference I will post a DJI Link where in you can check the DJI Osmo Action 3 Safety Guideline where in it includes some information on how to properly store your DJI Osmo Action 3's battery. Thank you.

https://dl.djicdn.com/downloads/ ... ines_5_lan_v1.0.pdf