Abstract A simple low-cost battery charger based on a saturated controller is proposed for charging of lithium-ion (Li-ion) batteries. When the reference voltage of the closed-loop process is set to 4.2 V, the charging process resembles a constant-current and constant-voltage (CC–CV) charging strategy. The charging process can easily be shortened by raising the limit on the saturated controller. Experimental results are included to demonstrate the effectiveness of the charger. It is anticipated that the charger can be a low-cost high-performance replacement of existing Li-ion battery chargers.