The second thread within that link may be the closest you’ll come to a “solution.”
MexicoMike shared his experience at Beat Buddy Power Supply Update
Several years ago Singular Sound announced an external battery (I think for a Summer NAAM) fur the pedal but I don’t think they ever manufactured or released it. If it had been feasible or suitable, they probably would have made one.
Some users have reported digital noise with their BB when using a battery or external battery power supply. Although your battery may provide power for up to 3 hours, this is probably going to be affected by temperatures. So if you’re looking for a commercially available solution, I’m sure you can find one using Google or Amazon.
If you find something that works for you, please reply to your thread to let others know.