I would like to share my story in the hopes that it will be useful to someone and also in the hopes that someone can contribute more useful information. I own a 2006 HCHII that I bought in June 2011 at 79K miles in Houston, TX. The IMA battery was mostly bad when I purchased the vehicle and as time progressed it became ridiculously bad with multiple recals occurring in the course of my 17 mile commute to work. No warning lights ever came on. I took the car to a local dealership before it reached 80K miles (still within the original warranty) to have the DC-to-DC converter replaced under a recall notice and at that time I complained about the recals and asked the service rep to record my complaint in his notes. No warning lights were on, but I was persistent and talked with the service manager about my battery problems. The dealership had almost zero experience working with hybrids, so I was basically teaching them about the HCHII using information gleaned from online forums (not a good sign). The service manager asked one of his techs do a quick diagnostic on my IMA system and battery. It showed that it had 18% charge capacity. The manager told me to just keep driving it and as it got worse the light should come on then bring it in. Well, over the course of the next five months the frequency of the battery recals increased, but no light would come on. It was obvious that the battery was deteriorating, so I took the car in every month to have another diagnostic done (happily they didn’t charge me for any of the diagnostics) and have a tech look at the charge capacity of the battery, but the results were always the same. It would show 18%, which I knew was wrong, because the recals were getting worse. Side note: I would love to know the standards of deviations or error limits for the internal diagnostic system on the HCHII, because I believe they are quite large. I think that the software of the internal diagnostics is only reporting results based off of the most favorable assumptions. I am an experimental physicist and know that with any complex system involving electronics, mechanical components, software, etc. there are always assumptions and approximations. The manager told me that the capacity would have to fall below 15% before he could talk with the regional Honda rep about replacing the battery, which by then was outside the warranty. He told me that even though the problems started while it was under warranty I would have to pay for the battery out-of-pocket, but he would try to goodwill as much as possible. Finally, in mid-November 2011 when I took the car in for a diagnostic it briefly showed a charge capacity of 13%. Just one minute later the tech ran the IMA diagnostic again and low-and-behold it showed 18%. Crappy diagnostics! Luckily he had saved the data from his first diagnostic and we used that to convince the regional Honda rep that the battery needed to be replaced. They good willed 75% of the cost of replacement, but that still left me $680 out-of-pocket. The old NiMH battery was replaced with a lithium battery on 17Nov2011 at 88K miles. I was very happy that they installed a newer lithium battery instead of the old heavy NiMH version. I walked away happy to have resolved the problem, or so I thought. The car and the IMA system were working great for about four months then the recals started again. I have recorded every instance that I’ve noticed, which doesn’t account for the times it has probably recaled while my wife was driving (she drives our HCHII about 30% of the time). Battery Recalibrations - 12Mar2012 --- 9am, about 65 degrees, AC off - 22Mar2012 --- 6pm, 73 degrees, AC off - 4Apr2012 --- 6:30pm, 72 degrees, AC off - 12Apr2012 --- 6:30pm, 75 degrees, AC off - 13Apr2012 --- 1pm, 78 degrees, AC on - 14Apr2012 --- 2:30pm, 77 degrees, AC on - 16Apr2012 --- 9am, 65 degrees, AC off I averaged around 42 MpG with the old bad NiMH battery and around 48 with the new lithium battery, but this has been falling as the recals occur more often. Now I’m concerned that I’m going to have to battle with Honda and the dealership all over again to get the new battery replaced, which obviously has problems. They will probably say something like no warning lights are on and your battery has 50% of charge capacity, so we won’t replace it. If that happens, my response will be IT’S A NEW BATTERY! It’s not even six months old and already showing advanced deterioration. I’m willing to fight hard to get this fixed. I dropped the car off at the dealership this morning so that they could examine it and perform another diagnostic. We’ll see what they say. Second side note: The class action lawsuit extended the warranty by 12K miles, so happily just a few weeks ago I received my $680 back. But unhappily, my car is now at 95K miles and I was told by a Honda customer service rep over the phone that because I am now out of the new 92K mile warranty that the battery is no longer covered. So even though the battery isn’t yet six months old and only has 7K miles under its belt it is out of warranty and I am potentially liable for any repair costs.