Wiring A129 Duo hardwire+power bank?

[BatanGTI]

I just ordered an A129 Duo and I'm trying to come up with a solution for the parking situation. I want the camera to at least run a time-lapse when the car is parked. I have found a few threads on the topic of hardwiring and power packs. There are some who run cigarette USB charger --> power bank --> dashcam. Then there are people who just run power banks only. etc. Then there is a talk about relays and battery separators... that's a possibility as well.
Now, the manual states that the camera can be powered through both ports. Has anybody tried connecting both? What happens if one port is getting the USB from the cigarette lighter and the other(say, GPS one) has a power pack plugged in? If the cam prioritized one over the other, the solution would be relatively simple - connect priority 1 to the cigarette lighter and have the power bank plugged into priority 2 for monitoring the parking. Power bank could be charged at home.
This is for my wife's car that got scuffed TWICE in the last two months while parked. So I want it to run permanently(the hit and runs were so slight they wouldn't have triggered a g-sensor even if there was a dashcam, hence the purchase). And with as little interference as possible from the user's end. Thoughts?
Thanks!

 

[VIOFO-Support]

Hello，

The dashcam doesn't support connect both ports meanwhile. We recommend you use a power bank for parking mode.

 

[Dashcamuser567]

I actually tried this on an old power bank but since it was an older one I guess it didnt support the feature set.

Basically I wanted the same setup you had without having to mess with fuses or extra hard wiring. Also with a 20,000mah battery will last longer than hardwiring in. I had it planned to be the car charger port --> power bank plugged in --> dashcam usb power port. Ideally the car when on would charge the battery bank which powers the dashcam. Then when the car is off the cam would still record since the battery takes over.

It worked for the most part except when I tried to charge the battery pack, I couldn't have anything connected to the bank. It didnt support simultaneous charging and discharging so the power bank died after about 2 days requiring an uninterrupted charge.

I am thinking about upgrading my dashcam but I do not want to deal with fuses or extra wiring is possible so I was going to revisit this but you need a specific type of battery bank that supports charging and discharging and possibly fast charging since having the strain on the battery being used would charge it very slowly.


Edit: Its called pass through charging: https://www.chargerharbor.com/what-is-pass-through-charging/