Slightly Higher Than Rated Output Voltage
I have one question recently i have checked the camera charger so the LED lit on while the rechargeable battery inserted but after a while it became dim and dim slowly. Then i have measured the output dc power of the charger it showed me 3.99 V dc. But the output voltage written on charger is 3.7V dc. so what could be the problem of this charger?
It is normal to have slightly higher than normal output voltage on charger. The voltage will come down to about 3.7 volt once the camera is connected. What you need to concern is that the voltage could have decreased to lower than 3.7volt causing the LED to dim while charging the camera. I suggest that you check the filter capacitor of the charger because the charger could have problem when under load.