21700 Battery Overview
The 21700 battery is a large cell lithium-ion rechargeable battery made for high-drain devices. Similar to the 18650, the 21700 has also been used to power electric vehicles. The 21700 comes in button-topped, flat topped, protected, unprotected, built-in USB ports for charging, and without USB charging ports. The 18650 is large enough generate between 3000-5000mah to keep your device running longer along with 300 - 500 charging cycles to provide a long lasting supply of power.