I have a powerbank by RavPower (RP - PB22) that worked fine charging my exposure strada. I think I purchased it 8 years ago so unlikely to find it now and its quite heavy for the capacity (13,000 mAh) but it worked as I had it charging both my garmin and my light. Suprised to hear you say most powerbanks don’t work. I will be following this thread as I would like to get something with a bit higher capacity.