Battery

Most portable power units contain a lithium-ion rechargeable battery and makes the largest component of an electronic cigarette. This may contain an electronic airflow sensor so that activation is triggered simply by drawing breath through the device. Other models come with a power switch, which must be held during operation. A LED to announce activation may also be equipped in the front of power unit casing.

Batteries are usually charged via AC outlet, car or USB. Some manufacturers also offer a cigarette-pack-like portable charging case (PCC), which contains a larger battery to charge smaller batteries of individual e-cigarettes.