Honda is extending its warranty on the Insight battery
Honda is worried about the battery found in the Honda Insight (2000 - 2004) and is volunteering to extend on the warranty for up to 10 years...

The batteries have had a "higher than expected" failure rate in some areas with higher than normal temperatures or in mountainous regions. The batteries tend to get overcharged during long descents.
In a service campaign, Insight owners in California, Arizona, Colorado, Florida, Hawaii, Nevada and Texas will be notified to get some parts changed at a local dealer.
Honda extends warranty on problematic battery of Insight hybrid