Resurrecting this thread for the title 
honourable mentions:
GL-AR750S +power banks. User experience
Powerbank for GL-AXT1800
I just picked up a Slate7 and have been experimenting with a few "pass-through" power banks this past week with disappointing results.
Short story is most of the units I tried featured USB-C power and worked great - until you plugged another cable into the power bank. Even if the cable has nothing connected, it seems to trigger USB-C power negotiation and drops power briefly to all ports 
Apparently larger units like Anker Prime do not have this flaw - they maintain uninterrupted power. Hopefully more units like this exist - I just want to maintain WiFi via the power bank, and plug into the wall to recharge when I get a chance.
Units I tried (Australia)
Cygnett VertPWR 25k (100W max USB-C PD)
Cygnett ChargePro 20k (30W max USB-C)
Both are great, as long as you don't plug or unplug anything which includes any dodgy cables / pcb connections which break contact if you wiggle the cable...
I'd love to hear others experiences. What power banks work best here? Is there enough demand that GL-inet starts putting (small capacity / buffer) batteries in their travel routers? (still need a power bank, but would solve brief power outages / moving the unit ...)