video

http://flashlightwiki.com/Rechargeable

cells can be salvaged from old laptop batteries (like I did) or can be bought separately. As our aim is to build a cheap but good , I recommend to search and find an old laptop

Cossatot 1000 XL Duty USB .

Non- vs. Batteries. Why Batteries? Things To Consider When Choosing For Your .

https://en.wikipedia.org/wiki/Rechargeable_battery

https://en.wikipedia.org/wiki/Rechargeable_alkaline_battery

Amazon.com: 18650 rechargeable flashlight

rechargeable flashlight 18650 | eBay

18650 Rechargeable Batteries – Walmart