Note: These batteries are bigger than a usual AA battery.
2 X I8650 3.7V 20r Rechargeable Flat Top Li-ion Battery/ 18 X 650 Solar Light
2 X I8650 3.7V Rechargeable Solder Top Diy Li-ion Battery / 18 X 650 Lithium
2 X I8650 3.7V Rechargeable welded Top Diy Li-ion Battery / 2000 mAh. 7.4Wh
6 X I8650 3.7V Rechargeable Solder Top Diy Li-ion Battery / 18 X 650 Lithium
6 X I8650 3.7V Rechargeable Flat Top Li-ion Batteries / 18 X 650 Wired