Sorry for my ignorance, but what is the function of the button on the charger? I never press it and everything works

You could use the charger, while one or more batteries are inside, also as power-bank - just connect your smartphone cable and press the button to charge your phone from the MMs batteries....

you can also use the button to turn it on and have it display the charge status of each battery

It is described in users guide, if you mean the dock for 3 bateries, it shows the battery level when pressed or you start power bank charging by pressing this button...

Thank you, I didn't read the manual completely because of the rush

Hi, thank you for bringing this query to us. You may refer to the information given by our fellow DJI members above. Also, you can press the function button on the charging hub once to activate charging if charging does not begin automatically and you can also check the battery level as mentioned above by pressing the function button once. You may refer to the manual link below. Please don't hesitate to reach us if you have other inquiries or concerns. Thank you!

https://dl.djicdn.com/downloads/ ... uide_v1.0_multi.pdf

Renato61 Posted at 2-6 03:42
Thank you, I didn't read the manual completely because of the rush

No problem, It is handy feature IMPOV...