Don't be scared of hybrid repair

Open your workshop doors to hybrid and electric vehicle servicing

Published:  15 January, 2015

By Nicola St Clair

I recently sat in on a training seminar hosted by Michael Parker of Autodata who was hoping to dispel any concerns independent workshops may have when it comes to servicing hybrid and electric vehicles (EVs). Although there are some important safety issues to be aware of, much of the servicing and maintenance remains the same so it is an opportunity to grasp now, as these energy efficient vehicles are already rising in popularity.

All hybrids and EVs have a motor to power the wheels and this also acts as a generator to re-charge the batteries. In many, this starts the engine, providing a seamless start-stop. Using an electric motor to get a vehicle to move is highly efficient, providing significantly more torque compared to the low RPM torque output of a combustion engine. In addition, 'regenerative braking' recoups the energy usually wasted in traditional braking systems. Hybrids still use conventional brake pads to stop the wheels at higher speed but as the driver depresses the brake pedal at slower speeds, the electric motors reverse direction and this torque counteracts the forward momentum and stops the car. When in reverse, this motor becomes an electric generator, feeding energy into a hybrid battery pack which is very heavy and packed with 1.2V cells that make up between 100V and 300V.

The Series hybrid is popular and utilises an internal combustion engine (ICE) and a motor/generator which drives the wheels and feeds the battery kinetic energy. At low speed/load, the engine can run intermittently to feed the electric motor or recharge the battery, at higher speed/load the ICE will run continuously to do this.

Parallel hybrid

Series Parallel

Plug-in Hybrid Electric Vehicles

Electric Vehicles

Service and maintenance There is nothing special in a hybrid service schedule, replacing brake pads and discs is the same. In all types of vehicle make sure systems are shut down in case a keyless ignition system kicks in! It is only when working on the well-protected high voltage system that is covered in orange trunking that specialist training is vital. The most important thing to remember is if you do need to work on the high voltage (HV) system, you MUST disconnect the HV battery.

The HV battery has a service life of seven to 10 years and some VMs lease them on attractive terms. The vehicles still have a 12V battery for lights and enabling the HV one to work, so they can be jump started.

The heating/aircon system uses a conventional liquid heater radiator and a normal AC refrigerated circuit but uses an electric compressor. It does not use PAG oil but a special polyolester (POE) oil which has a high insulation value. Using PAG oils around an electric compressor could be dangerous should an internal short occurs.

Mild Hybrid

Parallel Hybrid

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