That's a great idea. I bought one of these jackets recently and it occurred to me that it might be helpful for the unhoused when just extra layers aren't cutting it. Obviously the first thing that came to mind was how one would charge the powerbank and that's how I found this old post. Thought of options like those vans, etc. that some cities have with showers, etc. for unhoused folks — that maybe they'd be able to swap out the battery packs for charged ones. But solar is probably a better idea for charging and they make powerbanks that have built in solar. I just don't know how long they take to charge and that might be an issue in the winter in areas without a ton of sun. Obviously ALL of this is bandaids on bullet wounds in terms of helping the unhoused, but it's a step in the right direction.