When the units start exhausting, the prepaid meter starts giving alerts. These alerts are made using continuous built-in alarms that beep. Generally, the alert starts at about the 20k Wh mark. It becomes continuous and faster as you consume the tokens. When the token falls below 5k Wh, it becomes loudest and fastest at its peak. This continuous sound becomes irritating and annoying, specifically at night. However, there are many ways you can stop these sounds and maintain the peace of your place.