Electric Vehicle

Electric Vehicle System Overview

NOTE: The information provided in this chapter is specific to the electric vehicle. Chapters in this manual other than the engine and transmission chapters also apply to the electric vehicle.

Service and repair of the electric vehicle should only be performed by technicians that have completed HV3 Daimler Safety training. To prevent personal injury or death, or damage to the electric system, do not attempt repairs yourself.

The Saf-T-Liner C2 Electric Vehicle is powered by two batteries, and is a direct drive system with a two-speed transmission; there are no additional transmission or torque coupling devices installed on the vehicle. The motor torque and energy management strategy are controlled by the vehicle control unit (VCU) to maximize the overall efficiency and performance of the vehicle.

Safety Information

Electric vehicles are equipped with a high-voltage system. Do not attempt any type of electrical work on the vehicle unless you have completed HV3 Daimler Safety Training. Failure to do so could cause severe personal injury or death.

Warning labels are attached to high-voltage vehicle components. Some examples are shown in Fig. 18.1 . Do not attempt any type of work on these components unless you have completed HV3 Daimler Safety Training.

Fig. 18.1, High-Voltage Warning Labels

Regenerative Braking

This vehicle is equipped with a regenerative braking system. When the accelerator pedal is released, the electric motor acts as a generator in order to slow down the vehicle, while at the same time, send energy back into the batteries. When the brake pedal is depressed, regenerative braking is automatically blended with the mechanical braking.

The regeneration will feel as if the brake is being lightly applied when the driver removes their foot from the accelerator pedal. The full power of the service brake is always available to the driver, and regenerative braking is automatically shut off during an antilock brake system (ABS) event.

Tire Replacement

IMPORTANT: When replacing tires, the replacement tires revolutions per mile (RPM) must match the RPM of the original tires installed on the vehicle. This maintains the propulsion drive safety check performed by the drivetrain electronic control unit (ECU). It compares vehicle speed, drive motor (traction) speed, and antilock brake system (ABS) wheel sensor speed. If tires are mounted that differ from the factory RPM, the drivetrain ECU will detect an 'uncontrolled acceleration' event and disable the forward propulsion by shifting the transmission into neutral. Shutting down the vehicle and restarting the system will temporarily clear the fault.

Charging the Vehicle Batteries

IMPORTANT: The following battery charging instructions are used with the Proterra battery charging dispenser. If another battery charging dispenser is used, refer to the manufacturer's instructions to charge the vehicle batteries.

Perform the following steps to charge the vehicle batteries.

1.

Park the vehicle near the charging dispenser, turn the ignition key to the OFF position, and set the parking brake.

NOTE: The battery disconnect switch is located inside the battery box on the side-wall.

2.

Ensure that the battery disconnect switch is in the ON position. The disconnect switch must be in the ON position in order to charge the batteries.

3.

Open the charge port door, located behind the entrance door. See Fig. 18.2 .

NOTICE

Open the upper charge port cover first, then open the lower charge port cover; the upper charge port cover overlaps the lower cover. The covers may be damaged or broken if the lower charge port cover is opened first.

4.

Open the upper charge port cover first, then open the lower charge port cover. See Fig. 18.2 , items 2 and 3.

5.

Plug the power feed connector into the charge port. Push hard until a 'click' sound is made. See Fig. 18.3 .

1. Charge Port
2. Lower Charge Port Cover
3. Upper Charge Port Cover
4. End Charge Button - press when charging is complete.
5. Red LED - indicates a problem with the charger connection.
6. Green LED - flashes when charging; remains solid when charging is complete.
7. Charge Port Door

Fig. 18.2, Vehicle Charge Port

1. Power Feed Connector
2. Charge Port

Fig. 18.3, Plugging the Power Feed Connector into the Charge Port

6.

The green light above the charge port will begin to flash, indicating the batteries are being charged.

6.

The charger connected indicator on the instrument panel illuminates during charging. It can take up to 10 seconds before the indicator illuminates.

7.

The charging dispenser has a lamp to indicate the charging status. See Table 20.1 .

Charging Dispenser Lamp Legend
Lamp Color	Description
White	Available to charge the vehicle.
Green (communication)	Solid - charging dispenser is plugged up but not communicating with the vehicle.
Green (communication)	Flashing - charging dispenser is communicating with the vehicle.
Blue (charging)	Flashing - batteries are being charged.
Blue (charging)	Solid - batteries charged to 100% capacity.
Red	Out of service.

Table 18.1, Charging Dispenser Lamp Legend

8.

Once battery charging is complete, or to end a charging session, press the end charge button either on the vehicle charging port, shown in Fig. 18.2 , item 2, or on the charging dispenser, shown in Fig. 18.4 , item 3, then wait 15 seconds.

1. Charge Dispenser Status Lamp
2 E-Stop Button (for emergency only)
3. End Charge Button

Fig. 18.4, Charging Dispenser

9.

After waiting 15 seconds, ensure that the green light above the charge port is flashing rapidly. Then press the release button to disconnect the power feed connector. See Fig. 18.5 .

1. Release Button
2. Charge Port

Fig. 18.5, Removing the Power Feed Connector

Motor Starting and Shutdown

Starting

NOTE: When the charger is plugged into the vehicle and the ignition is on, the charger connected indicator illuminates in the instrument panel. During this time, the transmission can not be shifted and the motor is not enabled.

1.

Disconnect the vehicle charging cable, if connected.

2.

Set the parking brake, if it is not already engaged. See Fig. 18.6 , item 1.

3.

Turn the key fully clockwise to the START position, shown in Fig. 18.6 , item 2, and hold for approximately one second, then release the key. Wait for the motion enabled indicator to blink.

3.

The motion enabled indicator blinks when the vehicle is started. A blinking indicator means the vehicle is not ready to be driven. When the vehicle is ready to drive, the indicator stops blinking and remains solid.

1. Park Brake
2. Ignition Switch

Fig. 18.6, Park Brake and Ignition Switch

4.

Apply the service brake, then release the parking brake.

5.

With the service brake applied, press the desired mode on the shift control to put the vehicle in gear, then slowly release the service brake.

Shutdown

1.

With the vehicle stopped, place the transmission in neutral (N).

2.

Set the parking brake.

3.

Turn the key to the OFF position.

4.

Remove the key from the ignition switch.

NOTE: When the key is removed from the ignition, the high voltage is shutoff, but the instrument panel may remain on for 60 seconds.

Cold Weather Starting, Air Compressor

IMPORTANT: When operating the vehicle in cold temperatures, the air compressor may require a longer time to start up. Upon vehicle start, if the air compressor did not start up normally, or air pressure does not increase after 60 seconds, perform the key cycling sequence below.

Follow the steps below to cycle the ignition switch on and off in extreme cold starting temperatures.

1.

Set the parking brake.

2.

Turn the ignition switch to the ON position.

3.

Wait for 60 seconds, listening for the air compressor to start up. Pump the brakes if necessary to deplete the air tanks.

4.

If the air compressor does not start, turn the ignition switch to the OFF position.

5.

Wait for 15-30 seconds and turn the ignition switch to the ON position.

6.

Repeat steps 2-5 until the air compressor starts. This may take up to four key cycles.

Transmission

The Electric Saf-T-Liner C2 School Bus is equipped with a Proterra two-speed automated transmission. A push-button shift selector is used by the driver to select the transmission ranges. See Fig. 18.7 . When a gear is selected, the letter for that gear appears in the gear display window.

1. Drive (D) Button
2. Neutral (N) Button
3. Reverse (R) Button
4. Gear Display Window
5. Low (L) Gear Button

Fig. 18.7, Proterra Shift Selector

D (Drive)

The drive position selects the default start gear and automatically upshifts and downshifts. As the vehicle slows, the transmission will downshift automatically.

When going downhill, downshift to a lower transmission range to help maintain control of the vehicle. During downhill operation, the transmission may upshift to the next higher range, if the motor is exceeding its governed speed in the lower range.

N (Neutral)

The neutral position is used when starting the motor and for stationary operation.

When neutral is selected, the vehicle service brakes, parking brake, or emergency brake must be applied. Selecting neutral does not apply vehicle brakes unless an auxiliary system to apply the parking brake is installed.

Do not let the vehicle coast in neutral. If the vehicle is allowed to coast in neutral, the driver could lose control of the vehicle.

R (Reverse)

Always bring the vehicle to a complete stop before shifting from a forward range to reverse, or from reverse to a forward range. When the selector is in reverse, a warning signal will sound.

Do not idle in reverse for more than 5 minutes. Select N (neutral) when time at idle exceeds 5 minutes.

Low Gear (L)

Use low gear when pulling through mud or deep snow, when maneuvering in tight spaces, or when driving up or down very steep grades. Low gear provides the vehicle with its maximum driving torque.

Standard Instruments

Battery Charge Gauge

The battery charge gauge measures the level of battery power. A warning lamp illuminates when battery power is low. See Fig. 18.8 .

If a Low Voltage message appears in the instrument panel driver display screen, the driver should immediately shut down all auxiliary components including all heaters, air conditioner, and body fans. Move the vehicle to a safe location off of the road until the message clears or proper troubleshooting is completed. If these steps are not followed and voltage continues to drop, the electric vehicle may experience a loss of propulsion, possibly resulting in an unsafe stop.

1. Low Battery Warning Lamp

Fig. 18.8, Battery Charge Gauge

Battery Temperature Gauge

During normal operation, the battery temperature should register approximately in the middle of the gauge. See Fig. 18.9 . A warning lamp activates when battery temperature is above 120°F (49°C). The warning lamp deactivates when battery temperature is below 113°F (45°C).

1. Battery Temperature Warning Lamp

Fig. 18.9, Battery Temperature Gauge

Motor Temperature Gauge

NOTE: The motor icon under the gauge will never activate. Other motor warnings, such as the motor failure indicator, will activate in the instrument panel if a temperature issue causes motor failure.

During normal operation, the motor temperature should register approximately in the middle of the gauge. If the gauge registers high (H) and the motor failure indicator activates, the driver should safely pull off to the side of the road. See Fig. 18.10 .

Fig. 18.10, Motor Temperature Gauge

Primary and Secondary Air Pressure Gauges

If air pressure falls below minimum pressure, the braking ability of the vehicle will be limited. Slow the vehicle down and bring it to a gradual stop. Do not attempt to move the vehicle until air pressure has risen above the minimum level. Moving a vehicle without adequate braking power could cause an accident resulting in property damage, personal injury, or death.

Air pressure gauges register the pressure in the primary and secondary air systems. Normal pressure with the motor running is 100 to 120 psi (690 to 827 kPa) in both systems. See Fig. 18.11 .

1. Low Primary Air Pressure Warning Lamp
2. Low Secondary Air Pressure Warning Lamp

Fig. 18.11, Air Pressure Gauges

Air pressure gauges are required on all vehicles with air brakes. A low-air-pressure warning lamp and buzzer, connected to both the primary and secondary systems, activate when air pressure in either system drops below a minimum pressure of 65 to 75 psi (448 to 517 kPa).

When the motor is started, the warning lamp and buzzer remain on until air pressure in both systems exceeds minimum pressure.

Speedometer

Three kinds of speedometer faces are available. The U.S. version of the speedometer registers speed in both miles per hour (mph) and kilometers per hour (km/h), with mph in larger numbers. See Fig. 18.12 , item 2.

The NAFTA version (not shown) of the speedometer face reverses this arrangement, with km/h in larger numbers. The metric-only version (not shown) shows km/h exclusively.

Ametek Instrument Panel

The following information describes the various warning and indicator lamps found in the Ametek instrument panel. See Fig. 18.12 for an example of the gauges and Fig. 18.13 for an example of the warning and indicator lamps. See Chapter 5 for additional information and instructions regarding the Ametek instrument panel. Some instrument panel menus and sub-menus are not available on the electric vehicle.

1. Battery Charge Gauge
2. Speedometer
3. Battery Temperature Gauge
4. Primary Air Pressure Gauge
5. Secondary Air Pressure Gauge
6. Motor Temperature Gauge
7. Driver Display Screen
8. Toggle Button, Down
9. Toggle Button, Right

Fig. 18.12, Ametek Instrument Panel, Electric Vehicle (gauges)

1. Maintenance Warning Lamp
2. Left-Turn Indicator
3. Charger Connected Indicator
4. Motor Warning Lamp
5. Motor Failure Indicator
6. Performance Derate Indicator
7. Motion Enabled Indicator
8. Battery Warning Lamp
9. ABS Warning
10. Tire Pressure Monitoring System Indicator
11. High Voltage Interlock Loop Indicator
12. Right-Turn Indicator
13. Battery Failure Lamp
14. Low Air Brake Pressure Warning
15. Traction Control Indicator
16. Fasten Seat Belt Warning
17. Headlight High-Beam Indicator
18. Parking Brake On Warning
19. Low State of Charge Indicator
20. Cruise Control Indicator

Fig. 18.13, Ametek Instrument Panel, Electric Vehicle (warning lamps)

The instrument cluster has an emergency buzzer that sounds when serious conditions that require immediate attention occur.

A description of the standard warning and indicator lamps are listed below alphabetically.

ABS Warning

The ABS indicator illuminates when there is a malfunction in the vehicle antilock brake system (ABS).

NOTE: For more information about this lamp and the ABS system, see Chapter 12 .

Battery Failure Lamp

The battery failure lamp illuminates when the battery pack and/or the charging/discharging management system has a failure and needs immediate attention. Vehicle motor derate will occur.

Battery Warning Lamp

The battery warning lamp notifies the driver that there is an issue with diagnostics.

Charger Connected Indicator

The charger connected indicator notifies the driver that the vehicle batteries are being charged.

Cruise Control Indicator

The cruise control indicator illuminates when the cruise control is activated.

Emergency Buzzer

The emergency buzzer sounds during the ignition sequence and whenever one of the following conditions exists:

The air pressure falls below the preset level, which is 65 psi (448 kPa).

The parking brake is set with the vehicle moving at a speed greater than 2 mph (3 km/h).

Fasten Seat Belt Warning

The fasten seat belt warning indicator (seat belt icon) illuminates for 3 seconds after the ignition switch is turned on.

When the motor is operating, if the driver's seat belt is unfastened and the park brake is not set, the seat belt warning indicator illuminates and a warning chime activates. The warning chime will remain active for 10 seconds. The warning indicator remains illuminated until the driver's seat belt is fastened.

Headlight High-Beam Indicator

The high-beam indicator (sideways beam icon) illuminates when the headlight high beams are on.

High Voltage Interlock Loop Indicator

The high voltage interlock loop indicator illuminates when an open circuit (when a high voltage cable is disconnected from its component, or a high voltage component enclosure is open) is detected on the high voltage interlock loop. Take the vehicle to an authorized Freightliner dealer for service.

Left-Turn Indicator

The left-turn indicator flashes on and off when the left-turn signal lights are flashing.

Both turn signal indicators flash when the hazard warning flasher is turned on.

Low Air Brake Pressure Warning

The low air brake pressure warning indicator and emergency buzzer activate when the motor is turned on if air pressure in the primary or secondary air reservoir is below 65 to 75 psi (448 to 517 kPa), and remain on until air pressure rises above that level in both reservoirs.

Low Coolant Warning

NOTICE

The electric vehicle does not have a low coolant warning indicator. If the coolant level becomes low, a Check Primary Coolant Level or Check Secondary Coolant Level message appears in the instrument panel driver display screen. To avoid damaging vehicle components, the driver should immediately find a safe place to park the vehicle and call for assistance.

Low State of Charge Indicator

The low state of charge indicator notifies the driver that the vehicle batteries need to be charged.

Maintenance Warning Lamp

When the maintenance warning lamp illuminates, the message display center will alert the driver as follows:

Air Filter Reminder—the air filter requires checking or replacement.

Motion Enabled Indicator

The motion enabled indicator blinks when the vehicle is started. When the vehicle is ready to drive, the indicator stops blinking and remains solid.

Motor Failure Indicator

The motor failure indicator notifies the driver when the motor and/or powertrain management system has failed and needs immediate attention. Vehicle motor derate will occur. Take the vehicle to an authorized Freightliner dealer immediately for service.

Motor Warning Lamp

The motor warning lamp notifies the driver that there is an issue with diagnostics. The vehicle will need service soon.

Parking Brake On Warning

The parking brake on indicator activates when the parking brake is engaged.

If the vehicle is moving at a speed of 2 mph (3 km/h) or more, the emergency buzzer will sound until the parking brake is released.

Performance Derate Indicator

The performance derate indicator notifies the driver of a regenerative braking derate or a powertrain motor derate. If the indicator activates, the driver should safely pull off to the side of the road and have the vehicle serviced as soon as possible.

Right-Turn Indicator

The right-turn indicator flashes on and off when the right-turn signal lights are flashing.

Both turn signal indicators flash when the hazard warning flasher is turned on.

Tire Pressure Monitoring System Indicator

The tire pressure monitoring system indicator illuminates when the system detects an issue with one or more tires such as under or over pressure or over temperature. A warning message also appears in the driver display screen.

Traction Control Indicator

The traction control indicator illuminates when the wheels lose traction.

Towing

NOTICE

When towing or pushing the vehicle, regardless of the distance or speed traveled, either disconnect the driveshaft at the rear axle and support it as necessary, or remove the axle shafts. Failure to do this when towing the vehicle with the rear wheels on the ground could result in damage to the transmission and other components.

For towing instructions, see 'Towing' in Chapter 16 .

Jumpstarting

Jumpstarting electric vehicles is identical to diesel vehicles, which use the vehicle 12-volt battery system. See Chapter 16 for jumpstarting instructions.

High Voltage Battery Recycling and Disposal

The high voltage batteries used in this vehicle are eligible and recommended for recycling. Contact your local Thomas Built Buses dealer for high voltage battery recycling information. To find an authorized Thomas Built Buses dealer, refer tohttps://thomasbuiltbuses.com/bus-sales-and-support/find-a-dealer/.