There was a long and interesting story over the weekend in the Los Angeles Times about Honda Civic hybrids, their degrading batteries, a software fix, and its acceptability to the different interested parties involved.
Apparently, some of the batteries in second generation Honda Civic hybrids, which went into production 5 years ago, are failing prematurely. To extend the life of the batteries, Honda has developed a free software fix for the 2006 - 2008 Civic hybrids affected which Honda told the Times is designed to improve the car's performance.
The software fix, the Times says, ".. tunes the Honda hybrid system, known as Integrated Motor Assist, to limit cycling the battery, which means the electric motor often won't kick in to give an added power boost when accelerating. It also curtails how often the gasoline engine will shut down when the car is at rest, such as at a red light, a key fuel-saving feature in hybrids."
However, some Honda Civic hybrid owners are complaining that the software update may be indeed extending the life of their car's battery, but at the cost of poor gas mileage and sluggish car performance. One owner said his mileage had dropped from 45 miles per gallon to only 33, which the Times notes, is scarcely better than a conventional Civic costing thousands less. Other Civic owners, however, say they haven't noticed any problems after receiving the fix.
By providing the software fix, the Times story indicates that Honda has been able to avoid replacing the failing batteries, which are still under warranty. In California, there is a 10-year,150,000-mile warranty requirement on the components of the hybrid system. Honda's policy is not to replace hybrid batteries until they are completely dead.
Honda disputes that saving itself money was the reason for the fix. A Honda spokesperson was quoted by the Times as saying:
"This is certainly not a financial decision... This is not just to prolong the life of the battery, it also helps improve the [car's] performance."
The battery degradation issue has now caught the notice of both California and federal regulators because of potential environmental and safety issues. The Times story says that Honda has "swapped out more than 4% of the batteries in the 2006-08 Civic hybrids in California," which has exceeded the California Air Resources Board's "threshold for acceptable failure." The decrease in gas mileage in some of the Civic hybrids may violate state air pollution requirements as well.
The US National Highway Traffic Safety Administration (NHTSA) has become involved because of Civic hybrid owner complaints of a loss of power. Honda, the Times reported, believes battery degradation is not a safety issue, since the primary source of power in a Civic hybrid is its internal combustion engine.
The Times story notes that some Honda Civic hybrid customers are preferring not to get the software update after hearing about the possible performance problems. Some owners seem intent on replacing the 158-volt nickel-metal hydride battery themselves (estimated base retail price is $2,100, excluding shipping and installation) or are going to try and drive their cars until the battery completely dies, which will then have to be replaced under warranty.
It is an interesting engineering question whether the proposed software fix can really extend a Civic hybrid's deteriorating battery, by say an additional 5 to 7-plus years.
Any battery engineers out there who care to shed some light on the myriad of issues involved and the likelihood that the fix will indeed prolong an "abnormally" degraded Honda Civic hybrid battery's life through its remaining warranty period? For example, what is the "expected degradation" in a 158-volt nickel-metal hydride battery after 5 and 10-years, and what is the battery degradation level where the software fix is probably fruitless?
And are there any 2006 - 2008 Honda Civic hybrid owners who have received the software fix, and have experienced problems (or not?)