Arrgh! Summer Mileage

Discussion in 'Honda Hybrids' started by jmelson, Jun 23, 2009.

  1. psyshack

    psyshack He who posts articles

    No recals here that I know of.
  2. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    Are you sure it is a recal and not just a forced regen back to full?
  3. msantos

    msantos Eco Accelerometrist

    Hi kgenaidy

    Welcome to CleanMPG !!

    Yes, your experience is very familiar to us. For instance, just last evening we went out to eat with my wife's 07 and because it was pretty hot, the AC was on and conservatively set. Family was happy and car was doing good mileage wise.

    Everything was going fine until we encountered road construction and the traffic entered a stop and crawl. At that point when I looked ahead and saw the big lineup I knew an SoC crash was inevitable unless the traffic picked up some speed.
    Well, no more than 10 minutes later the SoC did crash to 1 bar and the ICE came on and stayed on until we arrived to our destination. Mileage? In the dumps.

    Such is life in the warmer weather with AC on and in Stop-n-crawl.


  4. kgenaidy

    kgenaidy Well-Known Member

    I'm not positive I am getting the term correct for what is going on ... but MSantos' description nails the behavior perfectly on the Soc and the re-charging.

    First couple of times this happened ... I thought something was "wrong" w/my vehicle. After reading articles on CleanMpg ... it helped me realize this is an expected and normal behavior.

    This board really helps a newbie like me understand and gain valuable insight into our vehicles.

    Thanks to all for the participation and information shared!
  5. psyshack

    psyshack He who posts articles

    I just spoke with the wife. She is very frustrated with the HCHII. She is on a trip from Okmulgee, Ok. to Stillwater, Ok. The car is showing 44.6 mpg on a fresh tank. She is driving the two lane hwy's keeping her speed between 55 and 60 mph. She does have the A/C on in auto mode set to 82f.

    She is not happy at all right now. Very pissed would be a understatement. She's said if this HCHII turns out to be a POS like the 06 Civic there will be no more Honda's at our house.
  6. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    Is she frustrated with the mileage or the handling?
  7. psyshack

    psyshack He who posts articles

    The mpg. The two lane roads shes on are not demanding at all. Some hills and over all straight. She is peddling the car and not using the CC. I checked the tires this am before I left for work in my always fun to drive MZ3. Heck I got 44 mpg out of the MZ3 this morning with a few high rpm stabs, A/C on some of the time running the psl. ( I was running late ) I did throw some fas'ing action in also.
  8. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    Okay. I can definitely understand her frustration but in the grand scheme of things, would she be even approaching that with her old car in these temps? Over all, I think her average fuel economy will more than justify the purchase and other than acceleration and "squishy" handling, it sounds like a very comfortable vehicle for her.
  9. psyshack

    psyshack He who posts articles

    She would only be getting 35 mpg in her Accord. But the fact remains. The HCHII has shown It will not get EPA at 65 and 70 mph with auto A/C use with CC. She is also finding out she has to work it to get EPA hwy at lower speeds with A/C. I have to work it to get 52 mpg this time of year hwy with auto A/C. While this good. It's still underwhelming considering the work needed.

    She could drive her Accord with out worry just keeping the speeds down and get or beat EPA city or hwy.


    She just called and reported back 45 mpg for the drive. She is at her destination and very frustrated with the mpg. She was expecting atleast high 40 mpg segment if not 50 mpg even.

    This is not close to what we expected. It's now looking like it might be hard to hold on to the expected lmpg of 50 mpg. I haven't posted the last tank yet. But at 51 mpg who's in a hurry. The heat is really hurting this car bad. Even with the A/C it's taken a nose dive. I will start looking into the intake air temps with my SG and see if a cool air intake mod is needed. Sure feels like it needs on something awful. It has got way gutless since the temps have went to the 100f mark. As of yet we have not seen a hard forced charge or a recal in the car. I left it for her after me driving it home yesterday with a full pack. First time I talked with her the pack was at 7 bars. Last time it was 6 bars. she said it never dropped below 5 bars for the trip that she saw.

    I know she is trying. This has her pissed!
  10. msantos

    msantos Eco Accelerometrist

    Hi Jeff;

    At 65-70 MPH? No way. Not likely you'll get EPA with the AC on, unless you set the AC to run on electric only and even then you're pushing it.

    It took me a good year or so to get my wife to nail the proper procedure on her HCH-II, but now she still gets good mileage without much of a miss when the temps are above 30C (86F). Stop and Craws are the worst, but steady highway speeds should not be.

    Still, your results appear consistent with the feedback from folks who drive the HCH-II at those speeds with the AC on, and that alone tells me it is "normal".

    Obviously if it still does not meet you expectations then perhaps that is enough to overshadow any of the other benefits the car has to offer.
    At least in that department, it appears our wives would have very different opinions and impressions the cars.

  11. hunter44102

    hunter44102 Well-Known Member

    Psyshack - also remember that MPG stated on the trip average display is usually understated on the HCHII. This means you could be getting better mileage than you think.

    So if your wife sees 44.6MPG, it could be 46 or 47MPG in reality. The only way to know is to divide mileage by a known tank (full would be best).

    On mine, if I get 50MPG average on the display, its almost always 52 or more based on real measurement.
  12. psyshack

    psyshack He who posts articles


    I realize that high mph will degrade mpg. I just would have thought the new EPA numbers reflected higher speeds and AC / acc. use. But when the wife struggles to get EPA hwy with the car well below psl with A/C set in auto mode at 82f. That isn't right. And I struggle with it to get 52 mpg the last week or better since 98f to 102f temps have set in. It makes one wonder what is going on here. I honestly think it's the intake air temps being high. The A/C is more than likely a 4 mpg hit right off the bat.

    I will try to infestigate the IAT when the wife gets home tomorrow with the SG1.

    A side note: I did get EPA hwy when I took the MZ3 out at lunch to run over to my daughters. Drove it slow, A/C full blast all city driving with no hypermiling except running under posted speed limits.
  13. psyshack

    psyshack He who posts articles

    The wifes car has been dead on at 52 mpg mark and under. Once it reports more than 52 mpg it then is off in mpg's favor. And I have seen it at 2 mpg or better. My MZ3 is always 1.5 to 2.0 mpg off in my favor,,,, like clock work. :)
  14. jmelson

    jmelson Well-Known Member

    How do you get the AC to run on electric power only? I'm not sure that would be an energy saver except in the case of a lot of down hills so you have regen to burn.
    But, I'd just like to know.

    I think I do get about EPA highway rating on the '09 HCH-II, but not much better. I am used to getting WAY better than EPA with most other cars, either city or hwy.

  15. msantos

    msantos Eco Accelerometrist

    The AC will run on electric only if the temperature differential between the ambient and the temperature setting of the climate control is low. To rephrase it, the electric half of the compressor will be used "exclusively" to perform small temperature corrections or simply maintain the existing temperature. The only thing we need to do is create the conditions for that to happen.
    The other time the electric compressor works is when it is being aided by the belt assisted half (to correct the biggest temp differentials).

    AC use is never a free deal as there's always loss to contend with. The question then becomes: How big is that loss and can we minimize it?

    Assuming that you will have at least a few unavoidable opportunities to regen and that you are able to manage your electric assists, then it is also possible to make use of what you put in the pack for AC use. The alternative to this is for the vehicle to fire up the ICE and keep it running at an idle consumption rate that is not very nice - especially when you are stopped.

    It is too bad we do not have an easy way of seeing when electric only AC is in use, but you can still tell it is working based on the absence of the usual/expected engine load and the difficulty to bump your SoC up.
    In the most extreme of cases (I really hate these), you'll actually see your SoC take a steep dive depending on whether we're able to keep the SoC in check or not.


  16. R.I.D.E.

    R.I.D.E. Well-Known Member

    My guess would be the EPA tests do not include temperatures as extreme as you are experiencing. Ac use is very mileage costly regardless of whether the compressor is engine driven or electric driven. Even with otherwise lost regen you still had to gain the inertia with battery or engine.

    Idle speed losses (non hybrid) double with AC use. The cost is probably in the range of .2 to .3 gph for AC use alone. That is going to nail your mileage regardless of the original power source.

  17. psyshack

    psyshack He who posts articles

    Lets remove the A/C and my observations of higher speed. Just remove it. I should have never brought it up. My bad!

    Remove those two factors and I'm still seeing lower mpg and a laboring engine with a full pack at higher temps. My gut is telling me it's the higher intake air temps.

    Take our daily grind drive into Tulsa. If there is no wind the trip home is almost always better than the drive in. Of late with the higher temps the drive home has been a real chore.

    Last week when the higher temps set in on us I had a real good run into work. 81f no wind with my normal 55 to 60 mph speeds. Windows down radio blaring away. That was good for 67 mpg. Not elite but very strong. We decided when we got to my office to really try for a good day no matter what the temps as long as the winds did not kick up. The winds did not come up. The wife did great on her leg of the day. Mixed city/hwy came in at 52 mpg. I was just amazed she pulled that off. My turn came to get us home. No wind and it was hotter than heck. We loaded up on water put the windows down. Both of us expected a record day. Didn't happen. All I could get out of the car was 57 mpg for the trip home. The pack was in good shape. We decided there would be no more of that foolishness. The heat really took it out of us by the time we got into the house. We both expected to see a 70 mpg run for the drive home.

    What I noticed was a much more sluggish drive in the heat. It's like cold corn syrup at best. :) It was harder to get into SAHM in areas of the drive that should be a no brainer. SAMBA was even harder to get and glides became very abrupt and control became overly sensitive. Fake shift was gone.

    One thing that has surprised me is its city / small town mpg. The wife has been very clear she will not drive for mpg at all on her weekends. She just want's to get in her car and go. And she does just that. I've seen her park it with Okmulgee segments in the high 20's to low 30's. I on the other hand have no problems with segments in the 70 to 80 mpg range around our small little town. And have had several that went 101 mpg to my best at 106 mpg. The day I got the 106 mpg segment she was in the car with me and uttered " your sick " :)

    Just have to figure out this low mpg issue when the heat pours on.
  18. Taliesin

    Taliesin Well-Known Member

    Could it be the battery efficiency is being inhibited by the high heat causing a constant charging action (beyond the AC use)?
  19. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    I'll be very interested to see your colder air intake effects in those conditions.

    Taliesin, in heat the battery tends to want to discharge as that will cool the chemistry. Charging causes it to warm up. You can see it in relative propensity for assist and regen in different temperatures. Below zero, my Insight will throw regen very easily. In hot weather, it wants to assist like crazy when accelerating.
  20. Taliesin

    Taliesin Well-Known Member

    I wasn't sure, but it was a thought. Could it be that it's becoming so assist happy that it's causing a charge/assist cycle?

    Just kinda brainstorming right now. I know that this heat we are experiencing down here right now isn't something you are used to.

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