This LM2596 Step-Down (Buck) Constant Current and Constant Voltage (CC CV) Regulator can provide either a Constant Voltage (CV) or Constant Current (CC) output. With a variable output voltage range of 1.25V to 30V and variable output current from 0A to 3A, it is ideal for use as an LED or laser diode current source/driver, a battery charger, a lab current/voltage source, or to regulate the output of solar panels or wind turbines to charge energy storage batteries. It can charge most any size lithium ion cell to almost any voltage you need. This is an inexpensive way to charge those 4.30v and 4.35v cells, as well as LiFePo and many other cells that require different termination voltages. It is also a good way to charge smaller cells since you can almost infinitely adjust the charging current and output voltage.