21V 1.5A Charger for 5S Lithium Ion Battery Packs

This device is designed to safely charge a 5S series string of Lithium ion batteries under control of a BMS. Under no circumstances must this charger be used to charge an unprotected string of lithium batteries.

The charger design is based on a low power boost converter that up converts an input DC voltage to a a regulated 21V - 21.3V output.

The boost converter input current is rated for 2A maximum, hence the boosted output current will remain under 1.5A, so long as the input DC voltage remains no more than 15V.

Hence, the input voltage to this 21V 5S charger must always be held to no more than 15V.