> most people I know are already doing this, they're just doing it with a big lithium pouch cell coupled with a BMS/charge controller called a "battery bank"

Precisely. That means you can "not think about it" 4x as much as without it. One of those with USB-C in and a solar charger has gotten us by off grid for years, as well as perfect for long haul travel. No five minutes replaceable mucking about needed.

It's one thing, not a bag of 10, it packs slim, won't slow you down on an all-day all-night "Midnight Madness" scavenger hunt in NYC, and won't get you pulled out of line at the aeroport.