NHTSA Complaint #11182457 — 2014 MERCEDES BENZ B-CLASS ELECTRIC

THIS IS AN ELECTRIC VEHICLE. WHEN SLOWING DOWN THE PADDLE SHIFTERS CAN BE USED TO PUT THE CAR IN 'D-' MODE, FOR MORE AGGRESSIVE ENGINE BRAKING. THIS INCREASES THE RATE OF DECL WITHOUT USING THE MECHANICAL BRAKES. THIS HAS WORKED WELL FOR FOUR YEARS AND 65,000 MILES. TODAY THERE WAS A 'ONE TIME' MALFUNCTION. I DID THE USUAL 'D-' 'DOWN SHIFT' TO SLOWDOWN FROM 30 MPH, IN TRAFFIC, FOR RED LIGHT. THE CAR DID NOT AGGRESSIVELY SLOW DOWN AND I APPLIED THE BRAKES. I NOTICED THE CAR NEED EXCESSIVE BREAK PEDAL PRESSURE TO MAKE WHAT SHOULD BE A NORMAL STOP. I GLANCED DOWN AT THE POWER METER AND IT IS INDICATING POWER IS STILL BEING APPLIED TO THE MOTOR. THE INDICATOR WAS HALF WAY TO THE FIRST TIC AND DROPPING AS I SLOW DOWN. THIS IS ABOUT 25 AMPS POWERING THE MOTOR, NOT RECHARGING THE BATTERY. THIS AGGRESSIVE BRAKING INCIDENT IS NOT RELATED TO COLD THE WEATHER BATTERY PROTECTION MODE WHERE ENGINE BREAKING IS DISABLED UNTIL THE BATTERY REACHES MINIMUM OPERATING TEMPERATURE. THE OUTSIDE AIR TEMPERATURE WAS 40F. TO RECAP, WHILE APPLYING THE MECHANICAL BRAKES, THE ELECTRIC MOTOR WAS STILL PRODUCING POWER AS INDICATED BY THE AMMETER, STOPPING THE CAR REQUIRED MORE THAN THE USUAL AMOUNT OF BRAKE PRESSURE.