The principle of 3s lithium battery balanced charge is very simple, such as 3S battery, composed of 33, 7V batteries in series, fully charged each battery 4, 2V, the overall external 13V or so, balanced charge alternating current transformer, rectifier to get 13V direct current, with 3 electrolytic capacitors, voltage equalizing resistance to 13V, each capacitor on the obtained 4, 33V, and then with three The electrode tube makes a simple closed-loop circuit, which can control the charging switch and the current size, so that the three cells can be charged independently.