NHTSA Complaint #11631699 — 2018 NISSAN LEAF

I was traveling home from work at approximately 60MPH (speed limit) and I experienced a rapid drop in the state of charge from ~60% to ~25% in 15-20 seconds. I slowed the vehicle to 55MPH and it recovered most of the state of charge. When accelerating to 60MPH a few miles later I experience the same behavior and was forced to maintain 55MPH. I was forced to turn off the electric cabin heater, heated seats, and heated steering wheel as well. I have been able to recreate the issue if the battery is: cold (outside temperature less than 15F and the vehicle has been outside for 8+ hours), less than 60% charged, and put under high load (going up a steep grade/60MPH+) the vehicle will register a battery discharge rate of ~5%/second and continue until the vehicle puts itself into turtle mode, the load is reduced, or I assume, shut off. Battery discharge is "phantom" where the vehicle, when under less load (i.e. slower/slowing), will return to a higher charge, and when no load (i.e. stopped), will return to close to the original charge. Depending on how long the high load is maintained it can drastically reduce the real state of charge on the battery. The Nissan dealership identified it as at least one bad battery module, but no fault codes were registered by the vehicle outside of experiencing turtle mode. This issue forces the driver to slow down to reduce load on the vehicle and abrupt speed changes may be required to keep the vehicle operational. This can put the driver into a dangerous situation of being forced to slow down regardless of road conditions or other driver behaviors. If all of the conditions for the battery listed in the first sentence are met, the vehicle will register a rapid battery state of charge decline, it may indicate turtle mode is active (helps reduce battery load), and it will indicate low charge around 10% state of charge. I have personally experienced all of this as the driver, and any assumptions I have made I have identified.