I wanted to pass along something that I only learned a year ago... laptop computers have a battery pack which contain 4-8 "batteries" or what people who know call "cells". These cells are the 18650 batteries. If the SHTF real bad and you live near other people, there might be a million of these batteries probably half charged. You'll need to figure out how to extract them, but I've already extracted 20 18650 batteries from my dead laptops. Please note, there are warnings on the internet about dangers of extracting these batteries, so maybe search for more info before doing so? I have no relationship with any products I mention. I bought a couple of these Hatori 18650 flashlights for $8 and they work great... https://www.amazon.com/gp/product/B00RRKEQ3S/ref=oh_aui_search_detailpage?ie=UTF8&psc=1 This fan uses 18650 batteries, so if you're hot, this would help, but also, it acts as a powerbank so you can put in the laptop batteries to charge other devices. I have not used that fan, but have one similar to it. I also bought some empty powerbanks from banggood that I could put these batteries in and use them to charge up phones/tablets. If you have a powerbank with batteries in them, but your solar panels died or you have none, you might be able to swap out the laptop batteries you extracted and continue to power your phone/tablet. Thought I'd pass along this info that might be new to some of you as a million batteries that most people don't know have value could help you.