Tesla Model S 70D technology transplanted into the DeLorean DMC-12

Moving technology from one car to another is challenging enough, but moving technology from a 2015 electric drive car to a 1981 car is really challenging. Thankfully some things are consistent, such as the use of 12 volts for ancillary electronics (non-traction), and the use of hydraulic pressure to apply the brakes.

Table of Contents

System Description Gallery
Drive Unit

The Tesla drive unit is comprised of an electric motor, a "transmission", and a motor controller/inverter. The drive unit (using the inverter) converts DC power from the battery pack to AC power for the motor. The unit communicates with and takes instruction from the Model S through CANbus.Electric motors do not have a narrow 'torque band' like a combustion engine, so the transmission requires only one gear. Reverse is achieved by reversing the spin direction of the motor.The Model S70D rear motor weighs approximately 210 lbs and measures roughly 22 in wide (motor to inverter), trans final gear housing is 8" wide (shaft port to port), 13in tall, 25in front to back including the unit mount on front and back.

The TesLorean will be using a drive unit control module from HSR Motors (Jason Hughes).  This controls the drive unit as if it were located inside the original model S.

An alternative motor controller is available from Damien Maguire (EVBMW.com) that replaces the driveunits stock controller and permits direct control.

Tesla 259HP Drive Unit
iBooster Brake Master

The iBooster made by Bosch is a vacuum-less brake assist. The iBooster assists the driver pressing the brake pedal with an electric motor as there is no combustion engine to provide vacuum. The power transfer from the master brake cylinder to the wheels uses hydraulic fluid, consistent with non-EV cars. The iBooster is used on autopilot Model S cars, as the unit can be instructed, via CANbus, to press the brake independently of the driver.The iBooster only consumes power when braking is required. Prior EV conversions would use an electric vacuum pump and a vacuum reservoir to provide a standard brake booster with a vacuum supply. Vacuum pumps can make noise or cause a start-up delay while sufficient vacuum pressure is supplied.

Bosch Ibooster
Electric AC Compressor

The Tesla AC compressor is fully electric, integrating both an efficient scroll compressor and and an electric motor. Other AC compressors require to be belt driven from the motor or engine. This compressor takes electric power from the battery pack. The unit does not require a clutch, as the electric motor can be switched on and off as desired.

Note: I've switched to the AC compressor out of the 2014 Tesla Model S so that it can be easily controlled. The 2015 compressor is controlled with CANbus code and currently the control codes are unavailable. The 2014 compressor is controlled using PWM.

Tesla AC Compressor
DC-DC Converter

The DC-DC converter takes in 400v battery pack power and provides as output 12v (or other voltage level as desired) to powercommon automotive devices.

The DC-DC converter would recharger the 12v lead-acid battery when the charger is charging the main 400v battery.  The 12v lead-acid battery acts as a buffer when the car is operatiing, or as a backup power source when the DCDC converter is not enabled.

DC-DC Converter
Coolant Heater

The coolant heater uses high voltage power from the battery pack to raise the coolant temperature.  The heating level is set with a PWM signal to the Front HVJB.  The Front HVJB manages the power distribution to the heater unit to control heating levels.

Note: The cabin is not heated by 'hot coolant' (as in a ICE).  Instead the Tesla uses an electric heater called a PTC.

Electric Heater
Coolant Chiller

The coolant chiller is a heat exchanger between the AC R-134a system and the coolant system. The AC compressor provides compresser R-134a refrigerant to the unit, it goes through an expansion valve to lower the pressure and produce a cooling effect. The coolant loops also run through the chiller and thus the unit reduces the temperature of the coolant. I will need to add a solenoid valve to the coolant line to be able to activate and deactivate the chiller as necessary.

Coolant Chiller
Coolant Pumps and Valves

The coolant pumps and valves are used by the computer to manage the temparture of the main components of the car (drive unit, inverter, dc-dc converter, charger, battery). The computer manages the heating/cooling to keep the operating conditions of the components as close to their optimal temperature as possible.

There are two types of valves in the Tesla model S, a diverter and a 4-way.  The diverter can switch flow from one output to another.  The 4-way can route coolant to an inner or outer loop. The 4-way is critical to the Tesla thermal management goal of keeping the battery at a desired temperature.

Diverter Valve
Steering Wheel and Column

The steering wheel and column provide the standard driving signals (indicators, wipers, lights) and also steering wheel adjustment. Additionally the steering wheel has computer controls on the left and right hand sides. These buttons and scroll wheels allow the driver to interface with the computer while maintaining a hold on the steering wheel. The controls also include the PNDR selector stalk - which the DeLorean does not have as it has a manual transmission.

The buttons/scrollers on the steering wheel communicate with the Model S systems using LIN network protocol.  The TesLorean build will not use the Tesla steering wheel initially, pending further tests with physical interfaces, specifically a clock spring.

Tesla Steering Column and Wheel
High Voltage Distribution Box

The Front high voltage distribution box distributes battery voltage to the high voltage devices, i.e. AC compressor, cabin heater, coolant heater, DC-DC converter.

The coolant heater is controlled via PWM provided to the Front HVJB (to be fully tested).  The DCDC converter is controlled by CAN instructions directly to the unit. The 2015 AC compressor is CAN controlled, but the 2014 compressor is PWM.

While the unit routes a HVIL line through all the connectors, the unit itself does not stop functioning if the HVIL is unused.

High Voltage Distribution Box
High Voltage Junction Box

The high voltage junction box (HVJB) sits under the back seat of the Tesla Model S and pairs up with the charger (or chargers if dual chargers). It moderates the flow of power to and from the battery and charger, and from the charging and supercharging port.

The AC port inputs (from external power source) are connected by default to the 6 paired lines running to the charger.  When DC direct charging (super-charging) two contactors connect the DC input directly to the battery.

The HVJB connects to 1) AC or DC input, 2) Charger, 3) Front HVJB, 4) Drive Unit(s), 5) Battery.

The box shown is configured for US power (240vac single phase).  The European version takes three phase power, and thus has additional contactors. The 6 pairs of lines running to the charger carry the 3 phases of power. 

High Voltage Juction Box
PTC Cabin Heater

The Tesla model S cabin is heated using a PTC element that takes 400v directly from the battery.  The unit is controlled using CAN instructions.

The Positive Temperature Coefficient (PTC) heater is a resistor that increases its resistance as it heats up. This limits the current it can pull and regulates heat production.

The 2015 PTC heater appears to be CANbus controlled. As yet I have not decoded or gained access to the control codes.

PTC Heater Model S
10kW Charger

The Tesla 10kW Charger converts 240vac to 400+vdc.  The input power is provided by a wall unit providing up to 45amps (US single phase). The charger is connected to the HVJB (as per stock model S).  The charger controller has been replaced by a controller module engineered by Damien Maguire and programmed by Tom Debree.  Further programming is necessary to have the charger interface fully with the rest of the TesLorean control modules.

Damien Maguire (EVBMW.com) created replacement controller hardware and Tom Debree has made significant updates to controller software.  In the TesLorean this allows the Chevy Spark EV 2014 A123 battery modules to be charged from a J1772 wall unit. 

Tesla 10kW Gen2 Charger