The Bosch battery manual cautions to bring the battery to roughly room temperature before charging.
-Charging – Batteries should be charged in a dry location and at room temperature.
-Storage during winter – Store batteries in a dry location at temperatures between 32° F (0° C) and 68° F (20° C).
-Fully charging or fully discharging results in higher loading of the battery. The ideal charge status for lengthy periods of storage is approx. 30 to 60% or two to three LEDs on the battery indicator.
-Cleaning & care – Cleaning with a direct water jet is impermissible, in particular to protect the electronic components. Before cleaning the eBike, remove the battery. -Occasionally clean and lightly grease the connection port.
-Winter use – During winter use (particularly below 32° F (0° C)) we recommend charging and storing the battery at room temperature be-fore inserting the battery in the eBike immediately before riding it. For longer journeys in the cold, it is advisable to use thermal protective covers.
-Storage – Temperatures below 14° F (-10° C) and above 140° F (60° C) should be avoided.
-Transport – For transport, the battery should always be removed from the eBike and safely trans-ported in your car, for example.
-Inspection – Using a diagnostic unit, the dealer can check the health status of the eBike, especially the battery, and inform you of the number of charging cycle
Here is a link to the Bosch battery manual:
https://www.bosch-ebike.com/fileadmi...yGuide_WEB.pdf