Years I ago, I have a SLA battery which is powerful but extremely heavy, and then I made a bracket to use it as counter weight.
Later, I used 18650 batteries and it's much lighter. And it's about as powerful as SLA.
Recently, I used USB power banks and it's even more compact in size, and it's airline portable too!
Problem is that, some USB power banks will stop delivering current, maybe they want some sort of hand shakes between devices. I found a very old USB power bank which will keep on kicking with any load, and this is great.
The Sky Adventurer was now powered directly via USB, the Nexstar mount is powered via USB to 12V cable, and the GOTO Mark-X is powered via USB to 9V cable. Very neat and portable!