HCHII IMA Battery Recalibration

Discussion in 'Honda Hybrids' started by Mr. Kite, Aug 3, 2008.


How often do you experience battery recalibrations in your HCHII?

  1. never

  2. up to a few times a year

    0 vote(s)
  3. up to once a month

  4. more than once a month

  1. msantos

    msantos Eco Accelerometrist

    Hi Eric;

    Something we recommend to folks once in a while especially those who report behaviors similar to yours is to perform a power reset. Have you done that yet?

    To perform a power reset you basically follow this routine:
    1. Disconnect the 12V battery for a good 10-20 minutes.
    2. Then reconnect it and go for a short and leisurely drive around the neighborhood (for 10 minutes or so). You should drive until the SoC is fully maxed out at 8 bars. If it takes longer then that could be an issue for concerns. After this short drive park the car for the night and next morning look at the SoC. If it is still at 8 bars then all is OK up to this point.
    3. For the period of a few days, drive the car as gently as possible. This means keeping the RPMS as low as possible preferably 2000 RPM. The longer you can drive like this (a week or more) the better it is since this will impact the adaptive nature of the active algorithms.
    Let us know how it works out for you if you decide to do this. This has worked for many folks and may be of help to you too. Once in a while a power reset is a VERY good thing for every HCH-II.


  2. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    Too bad it can't be performed without a FE hit, but once used for prevention is preferable to large numbers of forced recals.
  3. MarcD

    MarcD New Member

    We're getting these about 1x a month - I'll start logging them against temperature (it's been a warm summer, but we live near the beach where it's foggy). We've also had a crash in gas mileage - from 38 - 40 indicated to 30 - 31. I'm trying to dig into what to ask the dealer to check out to diagnose that...any tips/links/suggestions much appreciated.
  4. ShormanM

    ShormanM New Member

    Hi everybody! this is my first post.
    How is everybody's battery doing these days? any update?
    I was reading your experience with the frequent recals and you were talking exactly about the issues I am having.
    My driving is mostly in these conditions:
    My car is HCHII 2006 with 125k miles on it.
    -60F outside temp.
    -the car is garaged.
    -AC off but the fan is on all the time. i usually close the windows an use the AC fan to vent the car to keep the dust out.
    -urban driving with some short steep hills.
    -I get a recal almost every day.
    The SoC drops suddenly from 4 bars or so to 1 and kicks the recal process.

    Your updates guys about how your stories with the battery issues ended might be of a great help to me.

    Thank you!
  5. Jess

    Jess Well-Known Member

    Hi ShormanM,

    I still continue to have recals once or twice a week. I do what I can to maintain my SoC to avoid them, but sometimes there is nothing that can be done. The best thing I have done to my 2006 was to have it updated with the latest software update. This allowed more energy to be squeezed out of the IMA pack. I can now drive around on 4 bars SoC instead of 5 which gives me more opportunities to get it back up to 5 or 6 bars.

    I also try to keep assist to as few bars as possible.

    btw: welcome to cleanmpg!

  6. hunter44102

    hunter44102 Well-Known Member

    I have eliminated re-cals almost completely on my 06 HCHII which had them consistently

    The solution is to drive in 'S' until the car is warmed up, which means around 6-7 little bars on the temp gauge. (However if you are entering the highway, you would switch to D right after reaching about 45mph on the ramp - the key is to avoid as much assist as possible until the car is warmed up)

    I believe that using 'Assist' too much without 'Regen' caused my re-cals. I believe the IMA battery needs to warm up with some re-gens prior to a lot of assist. Driving in 'S' allows some regen to occur immediately, warming up the IMA battery.

    I have been driving about 35 days now with no re-cals
  7. Mr. Kite

    Mr. Kite Well-Known Member

    I am getting recalibrations on an almost daily basis--through various different types of weather. I performed the power reset cycle several weeks ago. Everything seemed fine with that. The recalibrations picked up right where they left off. I have not ever had the check engine light or the IMA light come on during driving. Also, I still have the original software; I have had no updates yet.
  8. Mr. Kite

    Mr. Kite Well-Known Member

    I did mention it to the dealer over the phone, but I'm really in no hurry to take it in. They don't seem to have a solution anyway. The FE is still doing just fine. My lifetime FE is 55.7mpg over almost 46K miles. It has come down, but that is also due to us moving to a new location and having some shorter commutes.
  9. Jess

    Jess Well-Known Member


    Do you really drive up to 45mph in S? I didn't think that was possible. I avoid S because I don't like the way the rpms jump up.

  10. kristian

    kristian Well-Known Member

    I've only had 3 or 4 recalibrations during the last month. I'm now running studded winter tires which have almost completely stopped me from gliding on my short 5 mile commute. The car is having to work a lot harder too (MPG is down to 37-40 range).

    Mr. Kite, do you still FAS whenever possible? I have a 2 mile steady downhill where my car is still cold and tried FASing on it. Both times, my battery crashed that afternoon on the way home so I stopped doing it. I'm not sure if the FAS caused the crashes or not, but I wasn't crashing daily before the FAS, and I haven't been crashing daily since.

    Edit: Jess, I've had it in "S" and "L" up over 60mph--think of the "gears" as software versions for the transmission instead of actual gears like in an automatic tranny.
  11. Jess

    Jess Well-Known Member

    Huh, interesting. I may have to try that in the morning.


  12. hunter44102

    hunter44102 Well-Known Member

    In my case, the power reset (and new 12v battery) didn't fix the re-cals either, but it was a good test, since I wasn't the original owner

    I have gotten really used to driving in S for warm up. It not only keeps the recals from occuring, it keeps the IMA battery at a higher charge because of the re-gens.

    I also recommend driving in S in heavy stop and go traffic. Driving in 'D' in heavy traffic seems to be the fastest way to drain the battery!

    I will be installing block heater this weekend so I won't have to stay in "S' as long and hopefully get a small boost in mileage also
  13. kristian

    kristian Well-Known Member

    Are you doing it yourself or having it installed? I have one on the MMH and have not found it worth the expense. If I plug the car in with a 3-4 hour warm up time, the cold weather mileage improved about 10%. However, when I factor the cost of the heater, the install cost, and the cost of the electricity, and the fact that it is a "one way device" (since I can't plug it in while out--only when at home), I will never come close to breaking even on it. I haven't even had the opportunity to tell any unsuspecting rubes that "this is where I plug in my electric car" like I was hoping.

    Also, I'm guessing the battery is on a different thermostat than the engine. The heater will help you get into auto stop and glide more quickly, but I doubt it will have an impact on cold weather charge/discharge behavior. Too bad there isn't an option for a plug in electric battery heater like on the pre-'08 FEH (something my 08 MMH doesn't have).

    If $$ isn't an object and you want to improve your FE, a heater is going to help but do it for environmental reasons, not financial reasons.
  14. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    It should also help the longevity of the engine slightly.
  15. ShormanM

    ShormanM New Member

    I finally got the IMA check engine light after all of this ReCals.
    I have to repair/replace the battery soon.
    Wish me luck!
  16. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    Good luck! I hope it is as painless as my battery replacement earlier this year.

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