US cities are inconsistent and I don’t know of an information source that profiles this.  When I travel here I make many phone calls in advance to find locally available resources!

Interesting Idea, couldn’t hurt to have them. For myself, my chair usually lasts a week+ on a charge, however I do carry a compact charger in a backpack with me everywhere just in case, just need an outlet. I have only used it once at a friends house when I forgot to check my level, I try to make sure I’m charged up prior to any long trips otherwise.