Recently put in an EU complaint form against Honda for using a small 12 volt battery in their Hybrid vehicles, specifically the 2009 Insight, that discharges after not being used for a few days. Dealer admitted that even their show room cars have to be jumped started after a few days of not being used and recommended either carrying a portable battery in the car, or disconnecting one of the battery terminals when the car is not used. Battery was tested by Honda (no problems) and they also checked for any electrical problem that could drain the battery; again, no problems were found. If car is used daily, no problem is noted. Is anyone else having this problem?

 

Honda didn't make a 2009 Insight.

I bought a 2010 Insight in April 2009 and have had no problems with the 12V battery even after the car has sat idle for 7-10 days.

 

Make sure none of the lights are on such as the one near the trunk lid. You must have a small drain somewhere. You can get a voltage indicator at you local autoparts store which plugs into your auxilliary power outlet to watch your voltage changes.