How We Do It
ENGINEERING AND DESIGN
The first step of this build was to evaluate the existing vehicle performance to determine which motor & battery configuration would provide the desired performance and range expectations. The engineering of a vehicle’s new drive line is especially complicated due to several significant design variables which vary per vehicle geometry and driver expectations. Specifically, weight and drag coefficient of vehicle, desired performance, required range, usable space for motor, battery and components.
ENGINEERING PROCESS: EARLY CONFIGURATION
At NomXd Motors, we start by selecting a motor which will match (or slightly exceed) the original gas engine’s output torque. On this build it was determined that that the Netgain Hyper 9 motor paired to the original transmission provides about a 48% increase in torque compared to the original gas engine. The calculations used to size the battery bank reveal that six Tesla S 18650 battery modules will provide the system voltage required and offer a range of about 100 miles.
Since the customer wanted to keep power brakes, a vacuum pump was added to provide vacuum to the brake booster. A vacuum storage canister and pressure switch was also installed so vacuum pump won’t run continuously. In order to provide heat and defrosting, a 1500 watt heater element was installed in place of the original heater core inside the heater box. The electric heater element is powered off the traction battery pack.
DESIGN VALIDATION / PROTYPING
With the internal combustion engine, fuel tank, exhaust system, cooling system, etc. removed, a mock-up of the Netgain motor with transmission adapter plate was done. The mock-up revealed that a battery box under the hood would not fit without significant modification (or eliminating the power brake booster) so it was decided to locate both battery boxes in the trunk directly behind the rear seat. The mock-up also provided an opportunity to position and mount the additional components required for the conversion. To expedite the prototype process, mock-up parts were 3d printed, rapid prototyped or made of sheet-metal, plywood and foam.
CUSTOM PARTS DESIGN AND ASSEMBLY
Upon completion of the mock-up, the custom parts are finalized in CAD and sent out for fabrication. CAD software was used to perform structural analysis on load bearing parts to make sure they will perform under expected conditions for the vehicle. At the same time as the CAD work is completed, the wire schematics are created for the HV and low voltage systems.
