I am new here and for the life of me manual, google, reddit, and forums have failed me.

I know one press and hold turns on and off buttons but what other functions does it do?  When I connected to my fpv and tried to press and hold it off, it went into a light show effect my drone led started to "dance" along with the battery led going up and down.  What other functions does it do and how long a press for the button?

i am not aware of any other button functions for the battery other than 1) turn it on and 2) turn it off.  in addition, you can tap the button and it will show status.  that's about it.  fpv batteries are notorious for being defective and if you see anything else, you might have a bad one.

Hi, DovahKiin117. Thank you for reaching out. Did it start beeping? It could enter the linking mode. The DJI FPV battery power button is used to power on or off the battery, check the battery level, and link the drone to the Remote Controller 2 or Goggles V2.
1. Press and hold to power on or off the battery.
2. Press the power button once to display the current power level.
3. Press and hold the battery switch for about 5 seconds, and the drone will enter the linking mode when it is beeping.

Hope this helps. If you don't think it enters linking mode, please provide us with a video of the operation. Thank you.

DJI Gamora Posted at 1-31 18:49
Hi, DovahKiin117. Thank you for reaching out. Did it start beeping? It could enter the linking mode. The DJI FPV battery power button is used to power on or off the battery, check the battery level, and link the drone to the Remote Controller 2 or Goggles V2.
1. Press and hold to power on or off the battery.
2. Press the power button once to display the current power level.

This is the correct answer, thank you!

DovahKiin117 Posted at 2-1 14:08
This is the correct answer, thank you!

Hi, DovahKiin117. No worries. I'm glad that I was able to help you out. If you need further assistance please don't hesitate to reach us here at DJI Forum. Thank you for your support and have a safe flight always!