New NiMH IMA Battery in 2006 HCHII Experiencing Problems

Discussion in 'Honda Hybrids' started by Mic123, Apr 17, 2012.

  1. Mic123

    Mic123 Active Member


    Good information! I hope your new battery works well for you, but if your experience is similar to mine then you might begin seeing recalls at the five month mark. Please keep us informed. When was your battery replaced? How do you plan on killing your battery if it starts recalls? I definitely plan on purchasing a Grid Charger for my 2006 Civic hybrid from Mike at but they're too expensive for me right now.

  2. Mic123

    Mic123 Active Member

    Just in case you're interested, here is my list of recals. I always round to the nearest half an hour.

    Battery Recalibrations
    1. 12Mar2012 --- 9am, 65°F, AC off
    2. 22Mar2012 --- 6pm, 73°F, AC off
    3. 4Apr2012 --- 6:30pm, 72°F, AC off
    4. 12Apr2012 --- 6:30pm, 75°F, AC off
    5. 13Apr2012 --- 1pm, 78°F, AC on
    6. 14Apr2012 --- 2:30pm, 77°F, AC on
    7. 16Apr2012 --- 9am, 65°F, AC off
    8. 18Apr2012 --- 2pm, 74°F, AC off
    9. 23Apr2012 --- 10am, 63°F, AC off
    10. 25Apr2012 --- 2pm, 80°F, AC off
    11. 30Apr2012 --- 11am, 78°F, AC on
    12. 5May2012 --- 3pm, 88°F, AC on
    13. 9May2012 --- 6:30pm, 80°F, AC off
    14. 10May2012 --- 1pm, 78°F, AC off
    15. 17May2012 --- 6pm, 79°F, AC off
    16. 18May2012 --- 6:30pm, 78°, AC off
    17. 19May2012 --- 1pm, 86°, AC on
    18. 23May2012 --- 6pm, 79°, AC off
    19. 24May2012 --- 1pm, 82°, AC off
    20. 25May2012 --- 6pm, 79°, AC off
    This doesn’t account for the times that it has recalibrated while my wife was driving and she drives it about 25% of the time.
  3. Jess

    Jess Well-Known Member

    That actually doesn't look too bad, Mic. I get at least two or three, sometimes four every single day. I keep a running log too. And if I don't drive it for a day, the next time it starts it will be with the coventional starter. I have about 70k miles on it and am just waiting for it to throw the IMA light before the warranty is up.

  4. Mic123

    Mic123 Active Member

    Dude, you do realize that you're comparing a six month old battery with only about 9K miles on it to yours that is ?4-6? years old and has over 70K miles?
  5. Bennett

    Bennett Well-Known Member

    Are these the 1-2 minute recals or the 10 minute full forced regens...?
  6. Jess

    Jess Well-Known Member

    Mic123, good point I don't know how I missed that. What truly blows me away about your situation is how Honda is saying that even though they just put the battery pack in, they are saying that because your car is past warranty, then so is the battery pack. That makes no sense to me. The pack didn't just morph into the rest of the car. It is a thing unto itself which is why they have a separate warranty for it.

  7. Mendel Leisk

    Mendel Leisk 2010 Prius (CAN Touring) Staff Member

  8. Spock

    Spock Active Member

    IMA replaced on 4/30. I guess maybe killing the battery sounds like I have a little more agency than how I actually expect the process to go: the only way I can think of to accelerate the rate of IMA deterioration short of actively sabotaging the battery (which however frustrating I may find the situation I can't recommend) would be to just abuse EV glide like crazy. If each pack has a limited number of cycles to its lifespan, then draining and filling the pack rapidly THEORETICALLY should help usher it out, plus at least your FE during glide is helping offset the increased recals. This tactic is probably best on the highway during light traffic where your variable speed isn't going to flummox other drivers and the recals aren't going to destroy your FE like in city driving.

    Having said that, I made no special effort to usher out my last battery: if anything I was driving to avoid recals as aggressively as possible, save when it made sense to help make the inevitably recalibration occur a might bit sooner, so as to not have it happen when least convenient.

    This is all kind of new territory and we're all sort of in no man's land until Honda makes a satisfactory solution to this problem, IE retro-fitting their lithium-ions for previous HCH models or the like assuming the new batteries are any better. I don't know what I'd be doing in your situation but I would DEFINITELY get the new flash if you haven't done it already. That is my personal recommendation and please decline if it makes you squirm. My personal experience is that for hypermilers this update does not significantly detract from fuel economy - personally I believe it is a modest improvement for most driving conditions (AGAIN, assuming you are hypermiling). You will get worse fuel economy accelerating up to speed in city driving - enough to make me understand why "normal" drivers have vilified the update so much - but everything else about it seems better. Either Herm or Harold mentioned that the update significantly improves SoC management as well and this has also been my experience. As I have said before, I also believe the flash is what actually finally caused my IMA light to come on.

    If you are not comfortable getting the flash, I would try nuking the pack through EV abuse on the highway and see what it does to your FE. If it only minimally affects it or it stays the same I would just keep nuking it every time you take a highway trip. Obviously I'm not an expert and that strategy is totally on you and at your own risk if you decide to do it - but it's probably what I would do in your situation while I was again, calmly, courteously, and persistently trying to get Honda to fix my battery.

    If we had MIMA you could not only destroy the battery faster, you could also try to bring some new life into it with a pack whack...but MIMA for the HCH-II doesn't seem to be a likely possibility.

  9. Spock

    Spock Active Member

  10. Mic123

    Mic123 Active Member

    I love the Pet Shop Skit!
  11. Harold

    Harold Well-Known Member

    It is very similar Mendel<grin> H
  12. Mic123

    Mic123 Active Member

    The Pet Shop Skit. Funny cause it's true.

    I had a second diagnostic performed on my HCH-II again this morning. Here are links to screen shots of the diagnostic window:

    Interesting to note that even though the calibrations have increased since the first diagnostic was performed one month ago the stupid internal diagnostic system reported the "IMA Battery Usable Capacity" at 35%. Last month the diagnostic reported 33%. I had a somewhat similar experience with getting my original battery replaced. The battery recalibrations were increasing dramatically, but every month for five months the diagnostic system would report that the usable capacity was 18%. Finally in November it briefly showed 13% and the technician got a screen shot, then it jumped back up to 18%. Ridiculous!!!

    I also talked with the mechanic about what he thought "IMA Battery Usable Capacity" meant and in the end we both came away uncertain. He did say that he asked the Honda Tech line about that very thing and the guy had tried to explain to the mechanic that it was the percentage left of the window that Honda allows the car battery to work within. (This is hard to put into words) In other words, a new HCH-II battery starts out at 5.5A·hr capacity and if Honda only allows the battery to be work within a range of 40%-80% (2.2A·hr-4.4A·hr) of full charge then this window represents the 100% of usable capacity. As that window decreases so does the usable capacity. I could accept this, but what about the new 2012 hybrid that we hooked the diagnostic tool up to and it showed a usable capacity of 49%. The new hybrid had a lithium battery, so the battery management system is drastically different, but I would expect the definition for usable capacity to be the same.

    My personal guess at what the numbers mean is that the usable capacity represents the estimated percentage of Amp Hour capacity left in the battery and the SOC represents the percentage of charge within the then present capacity. In other words, if my 5.5A·hr capacity battery is only at 35%, then I only have 1.925 A·hr available. And an SOC of 80% would be 1.54A·hr of charge capacity within the battery.

    By either definition a usable capacity of 35% is bad and that is reinforced/evidenced by my personal experience with the car. Crazy that Honda has set their definition of a bad battery at 15%.

    What are your thoughts? I'm curious what MSantos thinks about this. He seems to have a lot of insider knowledge, but I don't know how to get him to read this and chime in.
  13. Mic123

    Mic123 Active Member


    I'm not certain what the 1-2 minute recals might be that you are referring to. The recals that I experience take approximately 10 minutes to complete.
  14. Bennett

    Bennett Well-Known Member

    When I first got my HCH II it would go through several short recals a day, typically after "draining" the battery going up a long, steep hill or in prolonged stop-go city driving.

    The SoC would get to about 5 bars then drop precipitously down to 2 bars and enter a forced regen mode, charging up to 4 bars. Once it reached 4 bars a small amount of regen more and it would quickly tick up to 5, 6, 7, 8 bars in a few seconds and carry on as if nothing had happened. I could complete one of these by getting all the energy back on the downhill side usually.

    I think that's a recalibration rather than a true forced regen. I only experienced the 10 minute regens after Wifey and I took it on several hundred miles of highway driving, which seemed to truly max out the SoC. Those full regens are very unusual and require me to fully discharge the battery under conditions when I can't regen normally. I can only really remember one...I may have had another but can't recall when. I get almost no recal events now, but more 'normal' regen under steady driving and occasional 1-2bar regen with prolonged city driving, but the SoC remains at 4 bars while its doing this. The 1-2bar regen prevents the full 10 minute regen event.

    To summarize, the regens I currently experience are:

    • Hidden regen while driving. Randomly I acquire a bar of SoC without any obvious regen occurring.
    • 1-2bar forced regen when it gets to 4 bars SoC, taking it usually up to 6 bars. Autostop seems to still work fine in this mode. Regen only occurs when under power.
    • 1-2 minute recal events - drops quickly from 5 down to 2 bars, then forced regen losing autostop and regenning when stopped with 3-5 green bars of regen occurring. Once SoC reaches 4 bars it immediately recovers to 8 bars.
    • 10 minutes full regen events - drop to 2 bars once SoC is exhausted, forced regen losing autostop and regenning at idle. SoC seems to take forever to recover. No rapid tick-up.

    This is in a 2008 HCH, bought reconditioned (no idea what flashes it has - but it appears to be acting as if it's UTD).

    When I was getting all the recals I wished it would do SOME kind of minor forced regen. This behavior appeared once we made the long runs. I imagine we did something similar to what an overnight trickle charge would have done...:confused:
  15. Mic123

    Mic123 Active Member

    Sean (AKA Right Lane Cruiser),

    I was just rereading your first post to my thread and a few things popped out to me.

    If your information is correct, then on my test drives with the mechanic we never hit that sweet spot of low voltage and high temperature from any of the five-cell battery sticks to trigger a recalibration event. Also, how quickly the voltage drops while providing assistance might be another factor in triggering a recalibration. It would that all of the factors that lead to a recalibration event are not yet publicly known. Am I wrong in this thinking? It would appear from looking through my diagnostic screens that the battery temperature is monitored in only three locations and the voltage is monitored at only 11 locations and not at every five-cell battery stick. You were right, this truly is a simplistic monitoring system.

    Side question: Where did you learn all of this information about how the IMA system monitors and maintains the battery pack?

    Even though I said this in an earlier post, I feel it bears repeating. During my test drives I watched the 11 voltage check points closely and all of the values stayed close together (i.e. within 0.1 volts of deviation from each other). I had expected to see more variation in voltage amongst the 11 check points. We never experienced a recalibration during the test drive, so maybe a recalibration will only occur when one of the check points deviates strongly from the rest. Just thinking out loud.

    Also, if I understand you properly then you seem to be stating that the car's computer derives the value for IMA Battery Useable Capacity as seen on the diagnostic screen from its most recent recalibration event. Exactly how it is computing that value is still a complete mystery and a rather annoying one.

    Concerning the “New Old Stock,” according to the Honda customer service rep I spoke with Honda is definitely refurbishing the old battery backs. According to the Honda Mechanic’s friend in Honda’s parts division all of the five-cell battery sticks are new and I believe him. I doubt it would be cost effective to take time to check each of the old cells out and find which of them were reusable. I don’t know if Honda is replacing all of the electronics in the pack when it is refurbished. Sadly the refurbished battery packs must sit for long extended periods of time before they are ever sent to a customer, just as you wrote.

    Best Regards,

  16. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    Hi, Michael -- there are a number of known factors leading to a recalibration event but the precise ratios of each one in a given situation required to produce that result are not all known because the software hasn't been decoded. It is a complex multivariable equation and such a thing can be difficult to derive without massive amounts of data (which is rather difficult to collect in this case).

    As for where the information came from, I'm a voracious reader and much of this has been determined in a collection of threads over at InsightCentral. ;)

    Well matched cells will provide more capacity than cells which deviate by a good margin simply because the low voltage trigger point will be reached later. A recalibration event will occur any time the system discovers that its concept of the battery pack capacity is different than what measurements indicate when one or the other of the voltage extremes is reached. The computers keep track of remaining charge by counting amps into and out of the pack -- if it thinks there is more to go but suddenly finds the low voltage trigger is tripped it will go into a recalibration to both protect the pack (from cell reversal and permanent damage) and also to readjust its concept of actual capacity (or state of charge).

    There is also a high voltage trigger point but this measurement is largely used when the set point is reached when the pack is resting. For example, if you detached the 12V battery for long enough that the capacitor backups for onboard computers discharged, the car would forget what state of charge it had. If the resting voltage is high enough the car will do an almost immediate positive recal to read full. Most often though, the "top" of the pack capacity is determined by pushing charge into the pack until the voltage remains steady for some set period of time (dependent upon firmware version to some extent).

    Since the car is always counting amps in and out of the pack it can determine the capacity with known "empty" (low voltage trigger) and known "full" (voltage doesn't rise if more charging is performed) measurements.

    I don't have a definitive answer for you on the junction board (electronics) in the pack, but I believe that is also replaced when the pack is refurbished.
  17. philmcneal

    philmcneal Has it been 10 years? Wow

    sheesh it seems i cannot determine the life of the battery if I was buying a used hch II and the test drive was only 5 mins! It seems one needs a day with it to see how many recals it does before knowing the state of the pack :(
  18. herm

    herm Well-Known Member

    Who would buy a used HCH without budgeting for a new battery?
  19. all_about_the_glide

    all_about_the_glide Well-Known Member

    Exactly Herm,

    Best case scenario is that it is replaced under warranty, but the buyer should look at that event as a windfall, same as the rare event that the battery lasts the life of the car or lasts as long as it belongs to the buyer. Mine was priced more than a battery pack less than the Prii I considered to be equivalents.
  20. Mic123

    Mic123 Active Member

    It's been a while since I posted any updates.

    I took my HCH-II to the dealership again on 4Aug2012 to do another diagnostic. The car performed a recalibration while the mechanic was driving it and the “IMA Battery Usable Capacity” jumped back and forth between 33% and 35%. My car typically performs 2 recalibrations a day now, which I’ve kept a personal record of. In spite of all of this, at the end of the drive the mechanic said that it’s performing within spec and nothing was wrong with my IMA battery. Sometimes I wonder if these guys are really ignorant, or if they are just really good at parroting a memorized line while simultaneously turning off the ethical parts of their brains. How could he possibly say that my less than one year old new (newly refurbished) battery is performing within spec when it is recalibrating twice daily? That kind of behavior is hardly something to expect from an eight month old battery.

    I took screen shots of the computer diagnostic screen, but they don’t provide anything significantly more important than the last set of screen shots I posted, so I won’t bother posting them. I even filmed a movie (blurry because I used my cell phone) of the diagnostic screen while the car completed its recalibration, so you can see the SOC jump from 58% to 75%.

    I came across another class action lawsuit that seems to more closely fit my situation and argument (Jon Rego, et al. v. American Honda Motor Co., Inc., Case No. 12-cv-1193, U.S. District Court, Central District of California, filed on 10Feb2012, with Honda than the well-publicized one ( that is getting dragged out by the appeal. I really hope that the Rego V. Honda lawsuit gets some traction. Has anyone heard any updates on the appeal of the HCHsettlement lawsuit? The website hasn’t been updated since 21May2012.

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