I'm still unsure what happens when the SP3 is in connected stand-by and you take it outside at let's say -20 degrees Celsius in a car's trunk.
"Operating temperature. Surface is designed to work between 32°F and 95°F (or 0°C to 35°C). Lithium-ion batteries are sensitive to high temperatures, so keep your Surface out of the sun and don’t leave it in a hot car."
That's off the Surface web site.
This from research on LIon battery use in automobiles.
Cold temperature effects
•Battery performance (power, Energy) lower due to poor ion transport
•xEVacceleration and range are much more affected than conventional vehicles
•Passenger heating needed, BEV range is reduced using battery energy (higher gas emissions if engine used for PHEV and EREV)
•Charging is much more challenging as dendrite can grow and reduce life of battery and compromise safety
Id avoid leaving your Surface in the car trunk in -20 temperatures. MS should amend their site to include L-ion sensitivity to very low temperatures.
In your scenario, If all goes well battery life will be reduced and it will reach low charge quicker. In either 4 hours or at the low charge cutoff which ever comes first it should attempt to enter Hibernation. Given that the device is not in its operating range it may fail in unpredictable ways.
Additionally the thermal cycling alone will cause expansion and contraction causing mechanical stress and potentially damaging components and connections. Moisture could also form inside the unit from extreme temperature changes with predictably unpredictable negative consequences.
