Nearly 50 of Metro’s newest hybrid buses must be overhauled as part of a national recall because of a problem with the battery system, the transit agency said Wednesday.
The manufacturer of the buses, New Flyer, notified the National Highway Traffic Safety Administration on Friday that a problem in the lithium-ion battery energy storage system on its Xcelsior buses could cause an electrical short that is a potential fire hazard.
Over the past three years, 10 incidents have occurred on 2,200 of the buses used by transit agencies around the United States and Canada, the manufacturers told Metro. No one was hurt. And none occurred on the Metrobus hybrids, which are less than a year old, Metro spokesman Dan Stessel said.
The problem is not severe enough to pull the 47 buses from the road, he said. The manufacturers have certified that the buses are safe for use during repairs. Metro also plans to perform enhanced inspections during the work as an added safety measure.
New Flyer and the part’s maker, BAE Systems, will retrofit the buses, Stessel said, which means Metro will not have to pay for any of the parts or labor. The transit agency expects all 47 buses will be fixed in May.
The buses were part of an order of 152 hybrids that started to arrive last spring. One hundred of them do not have the same manufacturer for the battery parts, though. The remaining five have yet to arrive at Metro, Stessel said, but the parts will be replaced before they are delivered.
The recall is the latest flaw with the agency’s hybrid buses, which make up 27 percent of the nearly 1,500-Metrobus fleet.
In 2008, the agency had a problem with the first 50 hybrids it ordered. A microcomputer inside their Cummins engines was not properly sealed, so moisture seeped in, causing the engine to cut off while the buses were running.
Last year, a “fleet defect” affected 351 of the 401 hybrid buses it had at the time. The agency had trouble with roof-mounted cooling fans, the fuel injection and calibration on engines, and problems with the exhaust systems.
Stessel said those problems affected only the reliability of the buses and were not related to the current recall’s battery issue.
“Those were not safety concerns,” Stessel said.
Despite the problems, the hybrid buses have been the agency’s most reliable buses. Altogether Metrobuses averaged a distance of 7,275 miles between failures in 2011. But the hybrids run far longer before breaking down than the clean diesel, compressed natural gas or other types of buses in Metro’s fleet, with breakdowns coming on average after 9,718 miles last year.
