The Tesla Model S battery indicator bar is color coded green, yellow and red based on the percentage of charge remaining in the battery pack, but a new discovery emerged when KmanAuto caught a rare glimpse of a blue battery bar during cold weather and a low state of charge. Cold weather increases the internal resistance of the battery’s Li-ion chemistry thereby decreasing the charge capacity and range of the Model S.
NEW UPDATE – Jan. 7, 2015: ‘Charge Now’ message seen. Test conditions 9F, Firmware Version 6.0 (v2.0.77).
Many believe that the blue bar caught in the video signifies the allotment of energy reserved by Tesla’s onboard battery thermal management system as it attempts to warm the cold battery pack. Warming the Li-ion battery pack to an optimal operating temperature ensures that the battery chemistry is kept within a safe temperature range but also helps combat some of the common winter effects of the Model S.
Cool discovery but don’t try this at home folks.