It is expected that batteries will be charged daily in homes, parking lots of business establishments, on highways, and at convenience stores owing to the spread of EVs and PHEVs as part of measures against the sharp rise in the price of crude oil and measures against global warming to realize carbon neutrality in the future. Going forward, even greater convenience during charging work will be sought. The charging time varies depending on the battery size, the vehicle model, and the type of charging stand. Therefore, safe use of chargers and charging equipment with a voice or buzzer notification function to inform users about changes in the charging condition, including reaction, authentication, and warning sounds or a buzzer sounding in the event of a malfunction, secures peace of mind for users.