Hybrid Collision Repair: Safety First

Thanks to climbing gas prices, new tax deductions and growing environmental awareness, hybrid vehicles are flying off the lots almost as soon as they arrive. The more hybrids on the road, the sooner one will show up at your shop, especially since these more expensive vehicles are less likely to be considered totaled. Are you up to the challenge?

"Read, read, read," advises Mike Schoonover of Schoonover Bodyworks Inc. in St. Paul, Minn. "Read anything and everything you can to learn more about the vehicle."

Schoonover's shop has repaired more than a dozen hybrids. "All of our techs attended the I-CAR hybrid class, which was very informative," he said. "We purchased the necessary tools and safety equipment and bought a toolbox that is strictly used for hybrid repairs." The toolbox contained electrical lineman's gloves, which Schoonover identified as the most important item (see "Hybrid Safety Tips").

Education is essential to safely and successfully repairing a hybrid car. Technicians must be able to identify a hybrid's key electrical components, which generally include a high-voltage, nickel metal hydride (NiMH) battery pack; a 12-volt auxiliary battery; high-voltage cables wrapped in orange insulation; a power control device or inverter and a service disconnect. Always consult the manufacturer's service manual when repairing a hybrid vehicle, as each model is slightly different.

A proper repair also requires an accurate assessment of the damage. "We recommend checking the hybrid system for proper operation before repairing the body damage if at all possible," said Craig Totten, instructional designer for the Inter-Industry Conference on Auto Collision Repair (I-CAR). Severe damage to the expensive hybrid system could lead the insurance company to deem the car totaled.

It is important to keep the key off, out of the ignition switvh, and in a highly visible location such as on top of the dash board when a hybrid is in the shop.

All authorities agree: the most important thing to know is how to disable the high-voltage (HV) system. "This must be done before doing any work to the vehicles," stressed Totten. "It's like taking the bullet out of the gun."

Once the HV power has been isolated to the battery pack, techs can either avoid the battery during repairs or remove it after disconnecting the HV cables. When working on his first hybrid, Schoonover took no chances. "We had a technician from the Toyota dealership we work with come over to assist us with pulling the battery from the vehicle, which was a Prius."

Orange cables indicate high voltage. On this 2004 Toyota Prius, the protective sheath is shown.

Once the HV system has been disabled and/or removed, repairing a hybrid is, for the most part, business as usual. A few special considerations must be given, however.

First, take care not to subject hybrids to high temperatures. "Turn down the heat of your spray booth, as NiMH batteries don't like heat," advised Craig Van Batenburg, AAM, owner of the Automotive Career Development Center. While technically, normal bake temperatures can be used with proper monitoring, Van Batenburg recommends keeping the temperature well under 140 degrees Fahrenheit. He also suggests painting all hybrids at the end of the day and allowing them to dry overnight.

Totten noted that techs should use common sense when performing tasks like welding. "Don't apply heat right next to the battery pack without removing it first," he said.

A technician checks for the presence of voltage at the junction board terminals to the high-voltage battery after disabling the high-voltage system on a 2001 Honda Insight.

Low temperatures can also be problematic. Schoonover Bodyworks found this out during their first hybrid repair. "One of the things we learned was that the Prius cannot sit for two weeks or more in below freezing temperatures without the 12-volt battery going dead," said Schoonover.

Hybrids can be jump-started according to manufacturer instructions. A dead high-voltage battery, however, is another story entirely.

"[NiMH batteries] have a very high self-discharge rate, as much as 30 percent per month. Meaning if they are left sitting for a period of two to three months, they will go completely dead," Totten explained. "Running the gasoline engine on the vehicles is typically the only way to recharge them, so it is recommended to start a hybrid that is sitting every two to three weeks and let it run for 20 to 30 minutes to keep the batteries charged, as long as the damage does not make it impossible to do so."

A technician disables the high-volyage system in a 2004 Toyota Prius by pulling the service plug from the high-voltage battery. Notice he is wearing the high-voltage lineman's gloves while performing this important function.

Keeping the HV battery charged should be a top priority, as chargers for models like the Prius are rare and battery replacement is expensive. According to Totten, this problem is avoided in Honda models. "Hondas have an auxiliary 12-volt starter that can start the gas engine when the high-voltage battery is too low. Then the vehicle can be driven to recharge the high-voltage battery." HV cables may need to be replaced in a damaged hybrid. "Because of the high voltage carried, any damage to the insulation of the cables - even a pinhole - can result in a potential short," said Totten. Before handling any cables, techs should test them with a DVOM to make sure no voltage is present. Always keeping safety in mind, techs should also inspect their work afterward. "Ensure that the cables are properly routed and in the protective sheaths underneath the vehicle, and that all connections are torqued to specification before enabling the high voltage system," Totten advised.

Anyone who has worked on a Honda Insight knows that it differs from other hybrids in one important respect: its body panels are aluminum. More and more automakers are using aluminum and other lightweight material like plastic and laminated steel to improve fuel efficiency. While the Insight is the only aluminum-intensive hybrid currently on the market, aluminum is showing up in hoods, decklids, suspension parts and subframes everywhere.

Because of its unique properties, repairing this metal requires special techniques and equipment, such as a stud welder and an aluminum MIG welder. The equipment investment runs around $7,000 or $8,000, according to Mike West, collision chairman for ASA-Washington and owner of Southtowne Auto Rebuild Inc. in Tukwila, Wash. Which shops should learn to repair aluminum? Some say it's a question of cost/benefit, but West disagrees. "Everyone should know how to repair aluminum," he said. "Because Ford, Buick, Lincoln, Toyota, Honda all [use] some aluminum.

Schoonover emphasized the importance of gathering information about any hybrid vehicle that arrives at the shop. "We download the most current hybrid information from I-CAR and the OEM Web sites," he said. "We also utilize data from trade Web sites and magazines.

"As you do when working with airbags, always treat these systems with the respect they deserve," said Totten. "Once a technician understands these systems and knows the proper procedures to follow, the fear factor associated with them goes away."

Hybrid Safety Tips

Follow manufacturer instructions for moving a hybrid. Always tow with the drive wheels off the ground. Pushing a hybrid can generate electricity, so using wheel jacks is often recommended for moving the car around the shop.

Collision
These technicians have the tires on dollies to avoid charging up the condensers in the inverter by pushing the vehicle with the drive wheels on the ground. This is especially important if towing the vehicle with another vehicle and a towrope.

Always wear the proper safety gear, including electrical lineman's gloves. Following manufacturer instructions, disable the high-voltage system, test for any stray current with a CAT III certified digital volt ohm meter (DVOM) and avoid or remove the nickel metal hydride (NiMH) battery pack.
Make certain the system has been properly disabled before using welding tools, which can act as electromagnets and send power through the system.

A technician rolls up the rubber-insulated lineman's gloves to ensure there are no pinholes in them before use.
Use extra caution if you suspect the collision may have damaged the HV battery pack. Wear rubber gloves and safety goggles, as NiMH batteries contain a potassium hydroxide (KOH), a highly alkaline solution that damages human tissue. Potassium hydroxide also produces hydrogen gas, which is flammable when it contacts certain metals.
Neutralize a battery leak by spraying it with a diluted boric acid solution or vinegar. Use litmus paper to test for alkalinity. When the red paper remains red, the solution has been neutralized.
Talk with first responders in your area to verify they are prepared to assist in an emergency. Water can be used to extinguish a fire, even one involving the NiMH batteries, without the risk of shock or electrocution. However, hydrogen gas may result, as may a host of other poisonous gases in the case of a battery fire. Make sure your fire department knows how to handle a fire involving a hybrid.

- A.B.M.

Andrea Betts Menendez is a freelance writer based in Dallas. She can be reached at betts_menendez@hotmail.com.