How long does it take before the Intuvia rechargeable battery is empty if it is not used?

After approx. 5 months, if it was previously fully charged (usual winter break from November to March).

If the eBike will not be used for longer periods (more than two months), we recommend removing Intuvia and its fully charged rechargeable battery from the mount and storing it indoors at room temperature.
To avoid a particularly low state of charge of the integrated rechargeable battery, we recommend charging the Intuvia every 3 months for approx. 1 hour.