Looks like a pulse charge. I also have a green good with its own charger, quickly filled when the light is not sharp. Sometimes the light is red and sometimes the light is green.
It's either a problem or a pulse.
And its constant current is not really constant current, it is constant power. The limit power can be changed by changing the 0.5Ω sampling resistance of the high voltage part.
The true constant current is to charge a battery is also 3A or 2A current, and to charge N batteries is also this current value.
The charging current of the original charger decreases as the battery voltage increases. It was 2.3A and then it was around 2A. Then into the high constant voltage, the current continues to lower until the lamp current value. Turn the green light, turn the green light, and then change back to the red light to continue to fill, and then change back to the green light repeatedly.
The frequency of repetition is related to the current of the turning lamp, and the higher the current value of the turning lamp, the lower the repetition frequency.
The circuit is SDC3842+8N60C+LM358+ two 431(one for 2.5v precise voltage regulation, one for control optocoupler)
The original green light is very dark, the red light is super bright. Of course the voltage is the same. It should be considered that the green luminous efficiency of the dual-color LED lamp is too low.