What does it mean when an electric vehicle charger shows one red and one green light?
2 Answers
When an electric vehicle charger shows one red and one green light, it indicates that the battery is not fully charged. The red light will turn off and only the green light remains when the battery is fully charged. If the red and green lights flash alternately, it indicates poor contact. An electric vehicle charger is a dedicated charging device designed for electric bicycle batteries. The correct operation procedure for a switch-mode power supply charger is: 1. When charging, first connect the battery, then connect to the mains power; 2. After full charge, first disconnect the mains power, then unplug the battery connector. If the battery connector is unplugged first during charging, especially when the charging current is high (red light on), it can easily damage the charger. Common switch-mode power supply chargers are divided into two main categories: half-bridge and single-ended types, with the single-ended type further divided into forward and flyback converters.
I've encountered the situation of one red and one green light several times when dealing with electric vehicle charging issues, usually indicating an abnormal state from the charger. This is not a normal charging indication. The standard red and green light status should be a steady red light indicating charging in progress, and a green light indicating full charge. If both red and green lights are on simultaneously, it may stem from several common reasons: the battery temperature is too high triggering charging protection, especially in summer or after prolonged charging; internal charger malfunction, such as damaged components or unstable voltage; poor power or line contact—check if the socket and charging cable are securely plugged in. Once my car had this issue, I immediately unplugged the charger, waited a few minutes, and tried again. Sometimes it returned to normal, but if it recurs frequently, it's necessary to send it to a professional shop for inspection. Don't tinker with it yourself to avoid battery problems. Nowadays, chargers on vehicles come with protection functions, so it's essential to promptly address any abnormal indicator lights.
