so, I bought an adapter for my #FT857 that basically plugs into the power end of my radio and then into a cigarette lighter port, (I know, not the most efficient)
BUT, I plugged the cigarette lighter port into my #Jackery and the other end on my radio, and it powers up!
I just did a few test transmissions at 25W and 50W on #FT8 and was able to successfully make a few contacts!
looks like me doing #POTA / #ParksOnTheAir might be closer to a reality
For those curious, this is the adapter I bought: