Ring alarm battery backup only 15mins

So I have a Ring alarm. All works well except that the battery backup is only 15 mins NOT 24 hours as said. The base station would stay connected and powered on for many hours when it is connected over cellular data (subscription) when it goes onto battery backup. BUT since my wifi has a power backup for when power is cut the wifi will still be connected when the base station goes onto its battery backup. Only then it would automatically cut the connection to the wifi after 15minutes. This is NOT what was explained when advertised. How do I set the base station to simply keep the wifi connection on its battery power?