video

http://flashlightwiki.com/Rechargeable

The last,, is a -only cell about 150% the size of a AA and thicker.

http://www.batteryspace.com/M…

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

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

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

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

Amazon.com: 18650 rechargeable flashlight

rechargeable flashlight 18650 | eBay