Your SunVault system charges itself during the day so that it can power your home at night. In normal operation, SunVault will sometimes emit sounds up to 50 dBA while storing solar energy (charging) and servicing home loads (discharging). This buzz sound is associated with the storage inverter and vary based on the amount of power being actively converted. SunVault also has a fan-based cooling system that may turn on during operation or when the ambient temperature is elevated. This too is normal operation.