So I did some more testing with the USB batteries with the MP6 and I have and found some interesting results. I haven't done any run times on these, but will try to today (or soon).
I purchased a Anker PowerCore 20100 to use with this. It (sort of) works. Details on what I have below (and what happens when I use it with my MP6):
1.
Anker PowerCore 20100: Powers the unit with a FULL GREEN USB power bar. I get a very brief (1ms) flash that says
USB-C Power is low warning. Also get this if I unplug one of the USB-A sides. It seems to work fine since I have the AA's in there to fail back to, but very annoying to have the warning flash every few seconds. This unit claims to output 2.4amps on each USB output. Maybe I got a bad battery. Anyone have this issue with this battery?
2.
Jackery Giant+ Premium 12,000 mAh Dual. Powers the unit with ORANGE USB power bar. This unit claims to output 2.1amps on 1 USB / 1A on the other USB. I wouldn't use this unless I was desperate.
3.
Tecknet iEP390. Amazingly this seems to work the best. Powers the unit with a FULL GREEN USB power bar. Unfortunately it's no longer available to buy. Capacity is 9000mAh. This unit claims to output 2.1amps on 1 USB / 1A on the other.
On paper #1 seems like it there should be no issues...and the MP6 records audio with no issues with this battery.
On paper #3 should be the worst...but it works the best. Another bonus...it's small and fits in my bag easily. 9000mAh should get me though any normal show.
I'd really like to find a USB-C battery where I can just use 1 single USB-C to USB-C cable.
I can see why SD isn't making a list of "approved" USB batteries. The #'s on these things don't seem to add up.
So...feel free to add to the list. What do you have that is working for you and what doesn't.