>>398654281
I have a battery pack with high output and Quickcharge in my back pocket connected with an official link cable. I can play on Virtual Desktop while not losing any battery at all and charging instead if it wasn't full already.
It's a Swedish site, but you can see the exact specs of what I use so you know what to look for. The lowest I saw it at was 23% after 5-6 hours of play. 
https://www.netonnet.se/art/hem-fritid/el-batterier/powerbank/andersson-powerbank-20-000-pdqc-3-0/1004014.13728/