First choose the output voltage of the charger, which should be around 7.4V, preferably slightly higher than 7.4V; the output current is usually DC; The size of the output current first depends on your battery needs, otherwise, I recommend using 360mA, which can be fully charged in about 11 or 2 hours. Of course, if you think the charging time is too long, you can also choose one with a larger current. Charging time is slightly higher than 3600/charging current ratio. The charging current should not be too high, as this will impact battery life.
The above content is my personal opinion and is for reference only
Hello! It can be connected to charge, but we can calculate it. The output current of 8.4V is 1A. It is very likely that it cannot fully charge a 7.4V battery with a cocurrent of 3 A., and 7.4VX3A =22.2 W But they have a potential difference. 8.4V is higher than 7.4V, so it can be charged at 7.4V. Also, if you do this, pay attention to the charging time. . Ideally, this 7.4V 3A battery should be charged with a 7.5V power adapter with an output current greater than or equal to 3A. THANKS !