Improve Tado 'Green' credentials by provide better battery voltage data.
To improve the 'Green' credentials you can modify the app software to display the actual battery voltage.
This will enable use of rechargeable batteries (usually with a fully charged voltage of about 1.2V-1.3V, which work fine anyway.
Ideally you would ask what kind of batteries the customer was using so you could modify the 'battery low' message appropriately. However the battery voltage would be useable.