Dear customer,
The Netro app sends low-battery notifications for Whisperer sensor—please check if the app’s notification permissions are enabled on your phone.
When Whisperer shuts down from low power, the 0% humidity is just a system estimate. After recharging it, you might try resetting the Self-Learning function in the app to get accurate humidity again.
Also, check if the Whisperer is in a sunny spot with no obstructions—poor light leads to slow charging.
Let me know if you need any help.
Thanks,
Netro Support
Anyway it is a reasonable to not set the humidity to 0% when Whisperer battery is too low to send measurements to Netro.
Instead the system should maintain the last reading until a new reading is received.
Pls propose this to the dev.team.