B3 20W Simple Balance Charger is the best solution for 2S-3S battery because it is light and exquisite 20W maximum power charging current AC function especially the separation corresponding balance port for each battery pack. It is very appropriate remote control cars and helicopters. Performance and size parameters: Input voltage: AC 110V-240V; Balance charge current: 1600mA; Charging Power: 20W; Size: 92mm x 59mm x 35.5mm; Weight: 100g; Enclosure Material: Plastic; Display: green and red LED lights. Charger is connected: 1. first connect the power source B3 and three LED lights will turn green indicating that the charger is in good condition. 2. Next connect 2S or 3S battery balancing port and LED light turns red it starts charging the battery. Please note that if a battery is fully charged the corresponding LED will turn green. 3. All the LED lights turn green when the battery is fully charged.