I’m happy to report that I had a much better experience at the other dealership. The mechanic that examined my car was 10 times better than the previous mechanic and a really nice guy. He was able to tell me a few things about the IMA battery that I didn’t know and I was able to tell him a lot about the battery that he didn’t know. He let me ride around in my car with him while the diagnostic tool was hooked up. Then we took a 2012 Civic hybrid for a ride with the diagnostic tool (yes I know that it has a Lithium battery and not a very good comparison, but it’s still potentially useful).
Concerning whether or not the battery is refurbished or new old stock (meaning it sat on a shelf in a warehouse for an extended period of time), the mechanic contacted a friend in Honda parts who told him that the NiMH IMA battery packs Honda installs are refurbished, but all of the NiMH batteries that compose the IMA battery are replaced and possibly the accompanying circuit boards. In other words the parts guy said that Honda is not selectively replacing bad batteries within the IMA pack. This information seems to contradict what the Honda Corp. customer service rep told me over the phone.
The first time I spoke with the rep I asked him whether or not the batteries were new or refurbished. At that time he said he didn’t know, but would try to find out. A few days later I spoke with him again, and he told me that the IMA battery I received was new. This might be what he was told to say by his superiors or legal department. If something surrounding this ever went to court they could conceivably claim that the rep meant the batteries were new, even if the overall pack was refurbished. It could be that they’re both wrong and Honda really is just selectively replacing bad batteries within the pack.
On a slightly separate note, my Panasonic contact told me that Honda hasn’t bought any NiMH batteries from them for a couple of years (I think he said 2009), so Honda is getting batteries for their refurbished packs from another supplier. I learned that Panasonic and Toyota formed a joint venture, called Primearth EV Energy Co that made the NiMH battery packs for Toyota vehicles and then later began to sell them to Honda (http://en.wikipedia.org/wiki/Primearth_EV_Energy_Co
A hugely important point is the charge capacity, or as Honda calls it in their diagnostic software, “IMA Battery Usable Capacity.” The foolish mechanic at the first dealership I took my car to told me that I had 75% charge capacity, but he was erroneously labeling the SOC as charge capacity. While riding with the mechanic at the new dealership I was able to see that the diagnostic tool reads my battery as only having 33% charge capacity.
My first thought was, well here’s the problem, but then when we got into the brand new 2012 Civic Hybrid and the diagnostic tool showed that IMA battery as only having 49% charge capacity. The car only had 270 miles. This baffled both me and the mechanic. I really don’t understand what is up with these numbers. We wanted to look at another new 2012 Civic hybrid just to make sure that we didn’t stumble upon a 2012 with a mostly bad battery, but there were none available. Anybody have any thoughts about this? Honda Corp. policy currently is to not replace an IMA battery until its charge capacity reads 15% or less. Why would a new hybrid start out at 49%? Has anyone ever taken their new hybrid into a dealership and recorded the charge capacity of their IMA battery? I realize that probably no one has, because you’re not going to care when your battery is functioning properly.
The mechanic allowed me to take pictures of the diagnostic screen with my phone and I will try to post them up later tonight, but I need to remove the VIN from each picture first. I only took pictures of the diagnostic screen connected to my 2006 Civic hybrid. This is really interesting to me, because it shows what kinds of information Honda can get out of my car. Among interesting things of note from the diagnostic info, I believe that Mike from 99mpg.com mentions on his website that he has found 12 points in the HCH-II battery pack that are used for checking voltage, but the diagnostic screen only shows 11. I was speculating that the IMA system had been performing recalibrations because one of the voltage check points fell below a certain preset limit, thus preventing any of the 132 batteries from dropping too low in voltage and experiencing polarity reversal. I watched for this during the test, but we couldn’t get the car to perform a recal. We even tried deeply discharging the battery by stepping hard on the gas and then putting it in neutral while braking to prevent it from recharging the battery. We were able to discharge the battery down to one SOC bar on the dash (I didn’t record the percentage from the diagnostic tool, but I believe it was something like 22%), but the car stubbornly refused to perform a recal and once you get to a certain voltage limit it won’t give you any IMA assist, effectively preventing us from really deeply discharging the battery. The voltage at all 11 points stayed close to each other with only a few of them at times showing a 0.1V difference. Perhaps we weren’t able to deeply enough discharge the battery pack to see any of the batteries between the check points have a sudden drop in voltage. Mike from 99mpg.com demonstrates this on his website here, http://99mpg.com/Projectcars/understandingthech/
(Hit Cntrl+F and then type Civic to skip to the part where Mike specifically mentions the Civic), but it’s not entirely clear what he’s doing nor when he’s writing about Prius, Insight, or Civic battery packs. Information and graphs for all three battery systems seem to be mixed together. According to Mike’s data he had cells suddenly dropping in voltage when his overall pack was down to around 137V. I am not entirely certain, but if my memory is correct then the lowest voltage point we reached in our driving test was around 145V.
I will take the car back in about one month to perform another diagnostic with the same mechanic and then I will definitely record the lowest voltage point. We were able to take the SOC bars on the dash down to just one and it went into forced regeneration mode, but I’m pretty sure there wasn’t an accompanying recalibration. There were no sudden drops or jumps in the SOC bars and the SOC bars never reached the top. All of the recalibrations that I have experienced went like this: SOC bars at four, step on gas, receive momentary assist then assist stops, SOC bars suddenly drop to two, forced charge regeneration up to around 6 bars, then SOC jump up to the top. Anybody have any thoughts about why we couldn’t force the IMA system into recalibration, by discharging it in the manner I described above during our test drive?
Wow, that’s a mouthful! I am done for writing now.