True MPG of Clarity PHEV fully charged

Discussion in 'Clarity' started by geminiwave, Aug 7, 2018.

  1. insightman

    insightman Well-Known Member

    Yeah, what's up with that? The Clarity can certainly remember the battery's state of charge when you press the HV button. Why doesn't it use its regen and ICE resources to bring the state of charge back to that number after you delve into the battery's charge for passing or hill-climbing?
    Last edited: Oct 31, 2018
  2. RogerB

    RogerB Active Member

    Mine will generally rebound to the state of charge it had when I push HV. It swings around a fair bit, but will generally end up within a mile of EV range it had.
  3. Atkinson

    Atkinson Active Member

    Interesting side information on the HV button name:
    HV stands for High Voltage Battery "Keep" charge.
    HV Recharge, well, that one is obvious.

    The expectation is that the HV mode will retain battery level, but I think hills tend to consume more (or larger chunks) from the juice bank than HV would be efficient at putting back.
    Maybe Honda wanted to minimize energy transfer losses within the drive-train on bigger hills and just write it off the battery balance sheet.
  4. insightman

    insightman Well-Known Member

    I believe HV stands for Hybrid Vehicle because it switches the Clarity to operate like an i-MMD Accord Hybrid or 3rd-gen Insight (Honda's newest hybrid car).
  5. d99

    d99 New Member

    I've had my Honda Clarity PHEV for over a year. For many months, I reliably got 42 to 47 miles per charge. In early November, the dealer performed all the required recalls and I've never seen the same mileage since. I understand I will lose a few miles during the winter, but I live in California, not a winter climate. In December/January (when temps drop into the 40's during the day), the car was getting only 30-31 miles on a charge. Now that the weather is better, the car is getting 38-39 on a charge.
    The dealer tested the car last week and said there's nothing wrong with the battery. He was also in touch with Honda techs to troubleshoot. He also said that other Claritys the dealer is seeing after the recall are getting the same mileage I am.

    I'm not doing anything different -- driving the same speed, not using much a/c or heat.

    Besides the mileage loss, I have to listen to the very annoying loud motor when it's not running on electric.

  6. jdonalds

    jdonalds Well-Known Member

    This is pretty much my story. With 29K miles after 18 months I saw a drop for 48 to 38-43 or so more-or-less overnight in April. I think there is a problem. Honda does not. Sorry I don't have answers for you or for myself.
  7. thecompdude

    thecompdude Member

    Has the dealer done a battery capacity test for you? What is the score?

    Sent from my SM-N960U1 using Tapatalk
  8. d99

    d99 New Member

    THanks for the response. I will check with the dealer.
  9. d99

    d99 New Member

    The dealer response was that the battery is operating in "the normal range" and would throw a code (which would trigger a check engine warning) if otherwise.
  10. WindsorBoy

    WindsorBoy New Member

    I haven't noticed any difference using HV mode under this circumstance but, to be honest I seldom use it. Normally I just drive and if the battery runs down and switches to HV mode automatically I let it.

    On long (multi hour) highway trips I manually activate the internal charger to bring the battery back up to about 50% or more and then switch back to EV mode. This typically gives me an average of around 4.4 l per 100 km, or 53 mpg.

    My best consumption was over this last winter. I didn't mostly local trips and averaged .7 l per 100 km, or 330 mpg.
  11. KentuckyKen

    KentuckyKen Well-Known Member

    Your dealer is either ignorant or lying. The PDI specifically states that the battery will not throw a code if its capacity goes below the warranty threshold of 36.6 Ah.
    insightman likes this.
  12. MrFixit

    MrFixit Active Member

    I hate when you ask for a specific result like "What is the battery capacity", and you are told "It's OK". That is the classic non-answer. What you want is the numerical reading.

    Similarly, I bought the Clarity in November 2018. From this forum, I was aware of each of the relevant service bulletins, and I asked the service manager to demonstrate that these four service bulletins were installed... He looked up the VIN in his computer, and told me that "Everything was up to date". It was apparently not possible for him to obtain a list of what had been incorporated into the vehicle, just that "Everything" was OK !

    With respect to the battery capacity, don't settle for "it's OK". Insist on obtaining the numerical value. The number is especially important when you are experiencing anomalyous behavior. My dealer was able to produce the capacity number for me. If they don't know how to do it, the procedure is documented in the PDI list.
  13. 2002

    2002 Well-Known Member

    Nothing wrong with driving that way, but you will probably get somewhat better results not using charge mode on long trips. A better strategy for long highway trips is to start out with a full charge, but start in HV mode and stay in HV mode. On a long trip it will utilize the EV miles as needed even while in HV mode. Even though you are in HV mode you will probably see the EV range slowly go down on a long trip, but that's fine it is using the EV range judiciously when needed for efficiency. And it also allows you to drive in EV mode when you reach your destination if there is still some EV range left.
    David Towle, insightman and 228ra like this.
  14. WindsorBoy

    WindsorBoy New Member

    Last year I drove a few trips where I have was strictly in HV mode and compared this to similar trips where I used the existing RPM's to include running in charge mode. While there is definitely an increase in gas consumption while charging the ability to switch parts of the trip back to EV mode seems to more than make up for this and I honestly believe the net result is better gas consumption.

    Now, my experience may be unique. I find that if I've dropped down to zero bars (or the point where the HV automatically kicks in) and I activate charge mode I can get back to about 58% (or the point when it won't charger further) in about 70 to 90 minutes of highway driving. How long seems to depend on the terrain and driving conditions. I've found that a flat terrain with steady speeds works best.

    When I switch back I typically get 25 to 35 minutes of pure EV (again, this depends on the terrain) before the cycle begins again. So, I'm paying a bit more for gas during the charge cycle and getting some of that back during the EV only cycle.

    I'd be curious if others have tried this on a few long trips and what their experiences are like because I've heard a few people say that this is not a good strategy but my own experience is otherwise.
  15. 2002

    2002 Well-Known Member

    It's good that you are experimenting, that's the best way. Each drive (and driver) is different so it's best to find what works best for you. Some people use charge mode so that they will have more power on uphill segments, or at least so that they don't have to listen to a noisy engine going uphill with a low battery.

    On the trips where you used HV only, did you eventually switch to EV and use up the remaining charge before arriving home? If not that might partly explain why you did better starting out in EV. Also if you start your trips with a full battery but drive the entire trip in HV (except for the very end) did it maintain the EV range or did EV range eventually go to zero even though you were in HV and that is why you had to use charge mode? If so how many miles did it typically take to use up the EV range driving in HV mode?
  16. WindsorBoy

    WindsorBoy New Member

    On the HV only trips I drove on EV for the brief period that it took me to get to the highway (about 5 minutes) and switched to HV mode as soon as I was on driving on the highway. I didn't switch back to EV mode until I got to my destination. The trips were typically 3 to 4 hours each with a quick pee stop along the way.

    On the trips that I took where I toggled over to charge mode I have usually used up what charge I had before switching, however, the gas consumption estimates I gave were from some trips I took where the trips used only power generated by the engine.
    Last edited: Jun 4, 2019
  17. 2002

    2002 Well-Known Member

    It's a challenge to compare since we are mixing energy from two different sources. The best comparison is two identical trips where you start each trip with a full EV charge and a full tank of gas, and then end each trip with 0 EV charge as you arrive at the gas station to fill up, then compare the amount of gas used. The only difference between the two trips being whether you use the EV charge up immediately (and then use charge mode), or save most of your EV during the trip (thus avoiding charge mode) and then use up the remaining EV near the end of your trip before you fill up. For example if you are nearing the end of your trip and have 10 EV miles remaining, when the NAV says you are say 15 miles from the gas station where you will fill up then turn on EV and that will use the up remaining 10 EV miles before you arrive at the gas station.

    Really need to compare apples to apples, if you end one trip with some EV miles remaining and end another trip with 0 EV miles that's comparing apples to oranges. And I would ignore whatever the system is telling you about your energy use, just go by how much gas you had to pump, gas pumps don't lie. And since the total electricity used is the same if you use my method of going from 100% to 0% for each trip, you don't have to calculate the electricity used since it's the same. The only other variable is temperature (and rain, or traffic) so keep track of that in your log so that you can compare trips with similar conditions.
    Last edited: Jun 4, 2019
  18. Steve B.

    Steve B. New Member

    Our two kids live up near Los Angeles and my wife and I live in Orange County, and each of their respective apartments are just under 60 miles from us. So I've had several opportunities already to try a manual "HV Mode only" vs. an "EV Mode switched to HV Mode" and, like you just said, achieved in the low 50mpg range.

    I've read several posts and reviews, as well as watched half a dozen Clarity reviews. When MPG is discussed, several reviewers have attempted to 'beat' the on-board computer, seeking an answer to the question: "What is the real-world MPGe?"

    Bottom line? None of them could exceed what the on-board system could achieve. Turns out that's been my experience too as the on-board system usually "bests" me by 1-2MPGe and it's A LOT less futzing around while driving to just let the car do the work!
  19. 2002

    2002 Well-Known Member

    Just to confirm when you say "HV Mode only" I assume that you mean you start out in HV mode but at some point in the trip you switch to EV and use up all of the EV range before the trip is over. In other words when doing "HV Mode only" vs. an "EV Mode switched to HV Mode" comparisons, in both cases the trips end with EV range 0, correct?
  20. Steve B.

    Steve B. New Member

    Doh ... I wasn't clear. Yes, when I say "HV Mode only" I meant driving HV for the entire trip vs. "EV Mode switched to HV Mode" where *I* try to maximize my range by driving the entire way in HV Mode then switching to EV for the remaining miles until, like you say, being effectively at 0.

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