Just wanted to add that this unit works very well to power the RockPro64. I have a very mistreated unit (80% of original capacity) that I bought three years ago that still powers the RockPro64 with a dozen or so docker containers (mostly idle) for 24 hours starting at 75% capacity. It has a 12v barrel Y-plug so you can plug in the charger without unplugging the battery and a USB plug so you can add additional power to a USB hub for a 2.5" HDD. The charger that came with mine is only ~19whr, but if you aren't pegging the CPU 24/7 and your drive spins down, that is generally enough to allow the battery to stay charged over the long run.
I don't believe the 12v is regulated, so you might have issues when the battery gets toward the lower end, but it's worked well for me for this project (and others).
TalentCell Rechargeable 72W 132WH 12V/11000mAh 9V/14500mAh 5V/26400mAh DC Output Lithium Ion Battery Pack For LED Strip and CCTV Camera, Portable Li-ion Power Bank, Black
https://www.amazon.com/gp/product/B016BJCRUO
They also sell a 40w(I think?) solar panel kit for it.
I don't believe the 12v is regulated, so you might have issues when the battery gets toward the lower end, but it's worked well for me for this project (and others).
TalentCell Rechargeable 72W 132WH 12V/11000mAh 9V/14500mAh 5V/26400mAh DC Output Lithium Ion Battery Pack For LED Strip and CCTV Camera, Portable Li-ion Power Bank, Black
https://www.amazon.com/gp/product/B016BJCRUO
They also sell a 40w(I think?) solar panel kit for it.