Do You Need a Power Supply or a Battery Charger?
The terms “Power Supply” and “Battery Charger” are often used interchangeably, but they perform distinct functions.
A power supply is designed to supply a constant voltage to a load. As the load requirements change, it continues to supply a fixed DC level.
A true battery charger generally supplies a regulated current, first to charge the battery, and then switches to a regulated voltage mode. This is specifically required for Li-Ion chemistry where overcharging is not only damaging to the battery cells, but can also pose a possible fire hazard. A smart battery charger will not only never overcharge cells, but can also monitor battery temperature, switching off a fast charge when certain parameters are exceeded.
A power supply used as a charger cannot do this, and will continue to pump energy into a battery regardless of its condition; fully charged, battery fault, or shorted cells.
In order to achieve maximum battery service life, a properly designed charger should always be used to charge cells.