Hybrid vehicles bring with them new dangers to the technicians who have to work on them. While hybrid vehicle manufacturers designed these vehicles with an eye on fuel efficiency, Peter Zaidel, product manager, KPA, notes that the manufacturers also focused on the safety of service technicians.
KPA (www.kpaonline.com) is a nationwide leader in environmental and safety compliance programs for vehicle and equipment dealers.
He recommends sharing these fundamental safety basics for serving hybrids with service technicians:
1. How to identify a vehicle as a hybrid.
Almost all hybrids share three common identifiers, says Zaidel. They are:
- Hybrid badging on the body of the vehicle, typically the rear right section and under-hood identifiers, including the extra motor and the inverter.
- The “Ready” indicator inside the vehicle in the ignition area.
- Orange high-voltage power cables.
2. How to determine if the hybrid vehicle is really turned off.
“This may be the single most important safety factor for service technicians working in a shop where there are hybrid vehicles, because the hybrid system is silent when running on battery,” Zaidel points out. “Hybrid systems can automatically turn themselves off and on, switching between the high-voltage battery and the gasoline engine, so it is easy for the technician to be unpleasantly surprised that a vehicle thought to be ‘off’ is in fact ‘on.’”
He advises that technicians should observe the following service protocols. However, “since each hybrid vehicle and model is different, always follow the manufacturer recommended service safety procedures.”
- A hybrid is not necessarily powered off until it is verified that the vehicle is powered down.
- Keep vehicle keys a safe distance from the hybrid - more than 20' - as many hybrids have a keyless ignition, with on/off sensitivity up to 20' away from the vehicle.
- Always check the vehicle dashboard hybrid indicator to ensure the vehicle is truly “off” before any kind of work is performed on it.
3. How to protect one's self from high voltage.
While the amount of voltage and amperage in hybrid vehicles is enough to be fatal if a technician comes in contact with the high-voltage circuits, the high-voltage system does not ground to the body or the chassis, but rather is isolated from the vehicle body completely, says Zaidel. A technician would have to touch pole-to-pole or become part of the circuit for an injury to occur.
As a highly visible safety warning, all high-voltage circuits are encased and heavily insulated, and normally identified by the SAE standard color-coding of bright orange.
Never cut into, touch, mangle or otherwise disturb the big orange cables that carry the high voltage from the batteries (in the back) to the controller (in the front), he warns. Always wear Class O heavy duty gloves (lineman's gloves) rated to withstand 1,000V when disconnecting high-voltage components, such as the battery.
These gloves should be maintained in excellent condition and checked prior to each use to ensure there are no leaks, Zaidel emphasizes. Even a small opening can draw current that is seeking a ground.
Always disconnect the high-voltage hybrid battery before doing any major repair work or electrical work, he adds.
Most manufacturers also advise waiting at least 10 minutes before working on the vehicle after the battery has been isolated or disconnected. The high-voltage capacitors need time to discharge so there is no residual voltage to pose a shock hazard.
DIFFERENCES
“Hybrid vehicles may seem similar to gasoline-powered engine vehicles, and indeed there is much in common,” concludes Zaidel. “But the differences are important ones from a safety perspective, bringing risks of injury and even death to the untrained or careless service technician.
“Proper training, adherence to a company's service operations protocols and constant vigilance around these 'silent while on' vehicles will ensure a safe environment.”
David A. Kolman is editor of Fleet Maintenance, the only publication that provides a wide-ranging curriculum and best practices to enable readers to keep vehicles operating with greatest efficiency and maximum uptime, and improve their personal performance. An award-winning journalist, he has been actively involved in the North American transportation industry for more than 30 years.
