Make sure that the adapter is connected to both the charging station and the power outlet.
Fully charging a single battery usually takes 4 hours.
The battery will not be charged if the indoor temperature is below 5 ℃. Only charge the battery when indoor temperatures are between 5 ℃ and 38 ℃.
The battery will eventually need to be replaced. Due to the battery characteristics, runtime is shortened after using the appliance repeatedly for an extended period.