1. Connect the terminal of the secondary filter capacitor to the output voltage.
2. Short circuit BT 15 1. There will be electricity in the back. If the original circuit is restored after maintenance, or the source of BT 15 1 is directly measured, there will be electricity.
3. Just lead a 2 cm wire from the front end of the protective thyristor to the output end with battery reverse protection, but this charger should not be called "smart charger". Some smart chargers are charged by pulse voltage, and the derived voltage changes repeatedly.