The LiPo calibrator built is a very simple circuit based on the LM317, one resistor and one trimmer that can give a voltage from 4 to 4.5V. The trimmering range (around the point of start) should be minimezed in order to have a very good and easy adjustement with a standard multiturn trimmer. If the user has a very precise and stable power supply or another adjustable power supply (capable to be trimmered at 4.200V) it can be used to calibrate the LiPo balancer element.