Latest batch of software updates for the HCH-II (June 2010)

Discussion in 'Honda Hybrids' started by msantos, Jun 21, 2010.

  1. greenrider

    greenrider Well-Known Member


    So, is regularly charging the IMA battery to full a good idea then, say daily or several times a week for awhile? Would the fuel wasted be worthwhile in terms of savings from improved battery performance and longetivity? I could use at least a couple more years on it, without major IMA repair costs, until more PHEV options are available.
  2. msantos

    msantos Eco Accelerometrist


    The perennial enemy of these batteries has been, and will always be: The frequency and amplitude of the discharge/charge cycles.
    Keeping both of these down or to a good practical minimum is the absolute key to a longer lived battery pack... and also the key to good fuel economy in the long run. In fact, if done right the hit on MPG does not have to be that high at all. ;)

    To give you an idea:
    - My urban low speed commutes are no longer than 12 miles long each way and in the mornings I arrive to my downtown office parking ramp with 65-73 MPG. On my return trip later in the afternoon my MPG is lower (colder engine) but I still manage to hit 58-64 MPG. All this while keeping my SoC at a good healthy level.

    To achieve this, I use minimal electric assist which helps keep my need to regen to a minimum as well. However, if and when I must regen, I always pick the lowest cost regen possible and that means coercing the car into a hidden regen and keeping it there for as long as I require to ensure a good SoC of 6-7 bars. After all, the biggest MPG penalty is always incurred when a forced regen sneaks up on you, so whatever you do to avoid it can only help your MPG and your battery pack. ;)

    What I humbly suggest to anyone who got these updates especially after experiencing SoC crashes is to give the car and the software update a bit of a helping hand. For some folks this may not be an attractive option or even possible, but for others it will definitely help improve things. This "recovery process" can a bit slow but it is real and well worth whatever diligence and patience we can use on a daily basis.

    Lastly, we have to remember that as packs age, there will be a cell or two that will exhibit a lower capacity and if the combined SoC drops to too low a level these weaker cells have a chance of being permanently damaged!!! When this type of damage occurs, the pack is pretty much dead unless the modules that contain the offending cells are replaced. To avoid this situation we will want to keep the SoC as healthy as possible and for as long as possible. ;)


  3. greenrider

    greenrider Well-Known Member

    I've been charging the ima battery to full for several days now every day when I return home. That, combined with greater adherence to efficient driving techniques, even after long 14 hour days at work:rolleyes:, has helped my SoC to remain higher overall. MPG is up though I can't draw conclusions yet b/c of the varied driving style from norm lately (part of a road trip on the current tank) and favorable weather. I'm optimistic about "rehabbing" the IMA and I'd still like to use a grid charger/balancer at some point (anyone gave one for sale or loan in the Chicago/southern WI area?).

  4. ematzen

    ematzen Well-Known Member

    This all seems very reasonable, except that when I park my car the SOC is usually relatively full, and when I start it, it drops to 2 bars and causes a force regen. I imagine that isn't good for the car. Is there anything I can do to protect the IMA battery given this situation?

  5. jmelson

    jmelson Well-Known Member

    Well, I took my 2009 HCH-II in today, and they said there were no updates for this model. I did get an update applied in Dec 2009, and they said that had brought it up to date. This is in the US, I don't know if that makes any difference.

    Anybody know?

    I did get a block heater installed, we will see what that does.

  6. Harold

    Harold Well-Known Member

    I never see this kind of drop happening with my 2006 HCH. SOC only drops when it is being used. The IMA is not nearly as aggressive as it was before the up-dates. The car performs as well now as ever. :) H
  7. Mendel Leisk

    Mendel Leisk 2010 Prius (CAN Touring) Staff Member

    Jon, not sure, but: I think the updates are 2006-2008 only, and 2009 already has the newer software.
  8. msantos

    msantos Eco Accelerometrist

    Hi Mendel & All;

    Actually, the "newest" software especially the baseline announced in this thread is NOT present in any factory baselined 2009 models. It is also not present in earlier productions of the 2010 models either.

    Still, this has been a huge source of confusion made worse by conflicting reports from some in the media who were clearly deriving conclusions from the "damage control" PR choreography without being supported by a few of the underlying technical facts. Obviously, the public at large naturally builds on top of it and the rest is what we see.

    In any case, while this software update was developed to primarily address the "aging" issues of the earlier model years - in particular those that had been rarely updated and were sporting the original and extremely liberal BMP -, it has also been installed (under explicit guidance from Honda) on newer model years - especially on some 2009 models that have needed the correction.

    Lastly, I quoted the word "newest" in the first paragraph because in reality there's a good chance that it will no longer be the newest software for very long. If all goes OK, we will be announcing another software update soon enough. ;)


  9. Mendel Leisk

    Mendel Leisk 2010 Prius (CAN Touring) Staff Member

    This is somewhat disquieting: we continue to be guinea pigs in Honda's experiment, on our nickel. I'm beginning to accept that they will never get it right.

    I also wonder if 4.5 years with the "wrong" software has done irreversable damage. We're rolling along, post-update, with frequent recalibrations, state of charge that struggles up to 4 bars, then suddenly and miraculously shoots up to "full".

    Speaking of "we" (as in "we will be announcing"), are you connecting more closely with Honda again?
  10. dlister70

    dlister70 Active Member

    I hope that you are right.. the last one sure didn't do the trick.

    It's been a couple months now I think.. I am having recals two or three times per day, and my fuel economy is dropping all the time. I park it with a full charge, and the next morning it only takes driving a couple blocks to drop it down to 2 bars. Then it recharges to 4 and shoots up to full (sounds like what Mendel described too).

    Last week, I drove back and forth to the store a three times due to problems getting a prescription filled. It's about 1.5 miles away of in town driving, but only three stop signs between here and there. I had a full charge when I left the first time, and got a recal before I was even out of my subdivision. I got it back up to full charge on the way back from the store on the first trip, and got a recal again on the 3rd trip. I was not using much assistance, but it doesn't seem to matter.

    It's such a shame.. this car drives so great when the battery is charged. If they get the software to manage the battery better, it would be the perfect vehicle. :(
  11. OldMan58

    OldMan58 Member

    As a owner of a HCH II 2007 and a hypermiler, I used to get 60+ MPG in the summer and 50+ MPG in the winter (Vancouver Canada - hilly terrain). The overall average mileage for 3 years (~30000 miles, mostly on a 35 miles daily commute) was 55 MPG (with a 72 MPG high and a 50 MPG low) - excellent for the driving conditions in Vancouver. I was a very happy HCH owner... until the June/July 2010 firmware update.

    Now I get 45 MPG in the summer and below 40 MPG in the winter. There are some other reasons for the drop: a lot of construction and road improvements in Vancouver this year that make the traffic hectic. But I always plan my drives carefully avoiding the rush hours and using the side roads to avoid the construction areas.

    I know, some people will say 40+ MPG is still a good number. No! It is not. My average summer commute this year, after the upgrade, was ~50 MPG compared with ~60 MPG for the same period last year.

    What is worse is the loss of power -- the engine feels so underpowered now. I consider this firmware upgrade a serious safety issue. If my life would depend on this engine delivering in a dangerous situation, I would likely get injured or even worse...

    I've got almost stuck several times trying to go uphill from stop lights in intersections and I've got honked by other drivers who could not understand what the heck is going wrong with me or my car. Pushing the pedal to the floor without any visible effect on a 10% slope (uphill) can be scary sometimes, especially in a crowded area like downtown Vancouver where the traffic lights operate in short cycles without giving you much time to take off. The feeling is like the car is pulled by a long rubber band that is not under your immediate control. When it comes to traffic lights, Vancouver is particularly bad -- very few areas have them properly synchronized; keeping your momentum is a real challenge and anticipating the traffic light changes is even more so.

    I am convinced more than ever that the battery pack has issues and Honda is fully aware of them. The firmware upgrade has changed the battery management significantly. The “fix” extends the life of the battery by reducing the electrical motor ability to "assist" when needed. By doing this Honda hopes to avoid replacing the batteries dying prematurely on their cost before the warranty expires. I am very disappointed and I feel betrayed.

    I never heard of Prius having such problems despite of all the negatives Toyota has been going through this year.

    Honda screwed us big time with this one...
    Last edited: Nov 18, 2010
  12. msantos

    msantos Eco Accelerometrist

    Hi OldMan58;

    Have you communicated your observations to your local dealer? And if so, what was their response and what happened since at least on that front?

    The drop in FE you are reporting is quite substantial and it is quite evident you are not alone in making such claims. Keep touching base with your dealer and maybe you'll have some positive action coming your way sooner rather than later.

    As to whether this is update is a generally bad thing... well that is hard to tell since there are folks (myself definitely included) that are doing quite well with nothing detrimental to report or complain about.
    The "loss" of power is also something I sadly cannot relate to either and I suspect, there maybe something more that just what the updates (if properly applied) at work.


  13. Harold

    Harold Well-Known Member


    Something is not correct. I notice no loss of power in my 06 HCH2 since these up-date's. The IMA is manage different now but it is not effecting the power. Is it possible your CVT is not allowing lower ratio? H
  14. hunter44102

    hunter44102 Well-Known Member

    I will be putting the battery / update issue to rest next week.

    My 2006 is at 80K now (past warranty), and I will be installing a 2008 battery pack that I bought pretty cheap ($300). It had only 20k Miles on it and the guy kept it charged

    I conditioned(and re-balanced) the new battery pack, so it should be almost new.

    Hopefully I can boost my 45 hwy mpg mileage back above 50+, and get rid of the constant drops from 4 bars to 2, and continous recharging. I'm guessing my pack is deteriorated or has bad cells.
  15. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    What equipment did you use to condition and rebalance the new pack?

    Are you going to do the same to your original battery pack?

    Do you have any pictures? :D
  16. hunter44102

    hunter44102 Well-Known Member

    RLC - I used a BIO-RAD Power Pac 200 (200V adjustable DC supply with adjustable current limit and a timer)

    for now I just did a 're-balance' on this 'new' pack by applying a small current until the voltage won't go up any more. I watched it go up from the 167 volts and settle around 179. the voltage varies with temperature. Doing this should theoretically push the weak cells up while the good ones just disperse heat. They will effectively be the same and should prevent re-cals.

    for the old pack, I will see how many AH are remaining, and try to discharge/charge to improve it. If that doesn't work I would need to take the cells apart and try to do them individually, and possibly replace bad ones. Or I may just sell off the good ones and keep one pack.

    Pic of newer pack with charger applied:
  17. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    Nice!! Thanks for the picture. :)

    Is it hard to get at the pack in the HCH-II?
  18. OldMan58

    OldMan58 Member

    Hi MSantos,

    At the dealer I just found out that everything is fine and... in parameters! Hard to argue that everything is due to a firmware upgrade...

    If the battery management algorithm has changed, I admit that the driving pattern may need to adapt as well. On flat terrain and long drives I've been able to get reasonable numbers (between 52 and 56 MPG in the summer); but my daily commute is 65% up and down + a lot of road construction this year. This may explain in part my drop in FE to 45 MPG.

    But it is obvious that the electrical motor assist has diminished quite a bit and the time interval from start to full IMA assist is much longer. In addition, while driving uphill the battery gets depleted more rapidly, with all my efforts to maintain the load constant (up to the point where others seem to get frustrated behind me). Believe me, I keep my eyes on the instruments (including my ScanGauge) to know that I'm not too subjective. The tires are properly inflated at about 44 PSI front and 42 PSI rear - I know that they are ok if I can slide in the morning from my garage (just in neutral), before ignition at the bottom of the street.

    Two days ago I switched to my winter tires - the additional drop in FE was expected and on top of what I just posted in my last post (~4...6 MPG). I have a set of Nokian WR G2 tires that are good for the mild winters we get here in Vancouver. They are rated 51 PSI max pressure but I keep them at 44 PSI. This morning I managed a 48 MPG - just being lucky that the traffic was surprisingly light (last year in similar conditions with the same winter tires I've got about 55 MPG); not so good when I returned from work - just 41 MPG. It seems that keeping the car in the garage overnight helps quite a bit compared with leaving the car parked under the sky along the day (one more reason to keep the garage clean of junk).

    The thing that worries me remains the power loss: the additional torque coming from the electrical motor helped quite a bit. Now that I lost it, I’m really careful where I stop, I’m ready to turn on my emergency lights, I do not pass (except when forced by circumstances), and I use all the momentum I can get on these hills - it would be so nice if I would be alone on the streets 

    If I cannot get an answer from the dealer (and from Honda) I’m tempted to trade-in the HCH for a Prius while I there is some warranty left for the battery.
  19. OldMan58

    OldMan58 Member


    I remember clearly shifting into S or even L to change the CVT ratio and get more torque transferred to the wheels. However, this works well after the car reaches about 10 MPH. Between 0 and 10 MPH is the problem - basically, the electrical motor contribution is reduced -- here is where you feel the “rubber band” effect when start moving uphill and pushing the pedal to the floor does not help (does not translate into an actual change in acceleration). The effect is more obvious if the slope in 8% or higher.

    It is also possible that my battery pack is getting weaker and the new firmware is actually able to estimate better the battery state then adjusting the management algorithms accordingly (trying to preserve the battery life). I would be curious to know if my HCH would get back to life just by replacing the battery pack.

    The problem is to convince the dealer to replace it -- I doubt that this will actually happen -- I have no way to prove that the battery is running out of juice after ~4 years and ~35000 miles. And I doubt that the dealers have the equipment to recondition the batteries -- despite the fact that this is actually possible.

    I know a bit about NiMH batteries and the way you can refresh them (if not seriously worn out or damaged): two to three deeper than usual discharge/charge cycles at lower currents (yes, it takes a while between 20 and 36 hours). This needs to be done at the cell level (individually) and not at the pack level. I experimented with 2.5 Ah NiMH cells and it works quite well. It is also possible to test each cell for internal resistance in order to identify which cell is close to the end of its life or damaged (this usually happens prematurely if the cell overheats often). I have a smart charger/analyzer that helped me to understand a lot about NiMH batteries. Unfortunately, I cannot touch my battery pack while in warranty.

    The re-balancing suggested by hunter44102 isn’t effective in the same degree as the individual refresh described above but helps as well. I’m really curious to know the design of the battery pack and the way the ECU monitors the health of the battery. A good design would give access to the individual cells for real-time monitoring without opening the case for offline measurements.
  20. hunter44102

    hunter44102 Well-Known Member

    I think it might be easier than the Insight (just based on forum readings). I bought all the service manuals so that helps. Its just the same security bit bolts throughout (to take the cover and everything off).

    Oldman - yes its a bummer that Honda didn't make the cells accessible, or modular where you could remove, test, and replace sticks without taking much apart.

    I'm curious how the HCHII or other Honda's would perform if they had the same NIMH technology as the new Prius's. From what I've read, Honda is using older technology (panasonic) that was used only in the first few years in the Prius

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