I want to capture a video that will last longer than the installed battery can provide power for. Is it possible to connect a 26000mAh battery pack via usb without harming the OA and/or the installed battery? Should I remove the OA battery and just run the battery pack? Here is a link to the battery I want to use:
https://www.amazon.com/Intocircu ... product_top?ie=UTF8

Thanks in advance!

Hello and good day TriProt. Thank you for the inquiry and for posting this link.  I hope that you will get the best recommendation from our valued DJI Members who uses a power-bank in charging while using there DJI Osmo Action.  Just a reminder that we do not recommend you to use a 3rd party accessories or devices on your DJI Osmo Action. Actually, there is a  possibility that this accessory will work, however, since it's not yet tested by DJI we cannot guaranteed the reliability of the said accessory when in use. In addition using 3rd party accessories or devices might cause damage or harm on the DJI Osmo Action and can void the warranty as well. Thank you for your understanding and valued support.

Let us members Reassure you powerbanks work.   Just remember the camera is open to moisture.

Fishycomics Posted at 12-30 12:15
Let us members Reassure you powerbanks work.   Just remember the camera is open to moisture.

Thanks for the input Fishycomics. Do you keep the OA battery installed or remove it while using the powerbank?

I tried it on a timelapse and kept the battery in (probably didn't need the battery bank but I'm still getting used to the power consumption).  The battery bank seemed to just keep topping off the internal battery because it stayed at 100%.  You could probably use it without the battery just like it's using the external power source.

ebswift Posted at 12-30 15:26
I tried it on a timelapse and kept the battery in (probably didn't need the battery bank but I'm still getting used to the power consumption).  The battery bank seemed to just keep topping off the internal battery because it stayed at 100%.  You could probably use it without the battery just like it's using the external power source.

Right on, that was my concern if the OA battery was constantly being topped off then that could affect total battery lifetime or recharge %

This is where DJI Team members should have answered in the first place.   I used  years ago a Kodak ZI8, with a 5K powerbank. I tested things out.  Knowing not to allow this things to happen.

the Internal battery always got topped off or    being charged while recording.  It gave me 6 plus hours of non stop use. or 5 full battery charges.  From what I remembered.  What also happened was the Kodak ZI8 battery was full, the Powerbank depleted, the  camera started to charge the Powerbank because the Kodak was with more power then the bank.   I wonder if i can replicate that with the DJI.   

Yeah you would want he DJI not to be topping off as it goes through recycles and that can simply waste  power?