I had my IMA replaced under the extended warranty in Feb 2013. The battery is usually at 4 or 5 bars. When I go down a really long hill it charges and is at 8 bars at the bottom. Then after a few minutes, and assists, it's back to 5 bars. Frequently it goes from several bars of assist to being charged while going up a hill even with 4 bars of charge. Also sometimes to autostop works and sometimes it doesn't. Sometimes the engine autostops at 4 bars and sometimes it doesn't at 6 bars. Yesterday while accelerating all warning lights came on, this is not fun at night, and the IMA went off line. I pulled over and turned the engine off. When I re-started it only the check engine light was on. I took it to the dealer but before I got there the check engine light was out. I haven't heard from the dealer yet. Any ideas? Has anyone with a new IMA battery had this issue?

 

Curious if you know what % battery capacity you were down to before you got the IMA battery replaced under warranty? Hopefully Honda wasn't trying to tell you that the State of Charge % was the same as the % of battery capacity. Honda America told me the IMA light does not come on now until 10% remaining battery capacity - at which point the car is probably performing constant recalibrations per trip. Maybe your problem is New Old Stock (the battery has been sitting on the shelf a long time), or a refurbished battery, with a bad cell causing recalibrations. If you completely discharge the IMA battery and then trickle charge it back up to full, and it then performs normally, that would be your answer.

 

When the first battery was replaced it's capacity was at 17%. It was recalibrating several times per trip. Now the battery is OK again. According to Honda; they did a whole bunch of diagnostics free of charge; the problem could be a boost servo, or several other components. They basically have no idea and basically told me to bring it in when it happens again.