Clarity PHEV: real-world energy efficiency

Discussion in 'Clarity' started by Kieran973, Mar 12, 2018.

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  1. Kieran973

    Kieran973 New Member

    Hi everyone,

    This is my first post on this thread, but I've been reading it intensely for the last week or so and learning a lot.

    I was wondering whether anyone has any knowledge - either as data or anecdote - about the Clarity PHEV's energy efficiency in the real world. I read the entire thread about all-electric range, but what I'm specifically asking about here is efficiency - I'm particularly curious about speed vs. miles/Kwh (in EV mode) and/or speed vs. mpg (in HV mode). As an example of what I'm talking about in data form: Wayne Gerdes over at compiles some really awesome speed vs. energy efficiency graphs on all kinds of cars. Here are just a few, in case people haven't seen these elsewhere:

    Hyundai Ioniq HEV Blue:

    Hyundai Ioniq Electric:

    Toyota Prius Prime vs. Toyota Prius II Eco:

    Honda Civic:

    The reason I'm asking this question is that I'm thinking about buying a PHEV but I live in an area with high electricity rates. I'm also considering the Prius Prime and Ioniq PHEV, but for a number of reasons, the Clarity PHEV is at the top of my list. And so I'm trying to get a handle on what to expect in terms of average mpg in HV mode and average miles/kWh in EV mode. For example, if the Clarity PHEV averages 3.5 mile/kWH while the Prius Prime averages 5.5 miles/kWH, then at 20 cents/kWh, and driving 15,000 EV miles a year, the Prius Prime costs roughly $300 less per year to drive or $3,000 less over 10 years. Plus, it's still not clear to me how accurate the Clarity PHEV's 40 mpg EPA highway rating is. The latest generation Civic is also EPA rated at 40 mpg highway, but this is a drastic under-rating: I'm currently driving the latest Gen Civic, and in the summer, I can easily average 50+ mpg on a whole tank if I do mostly highway miles. In fact, yesterday, in 35 degree weather, I did a 250 mile highway trip with a lot of steep elevation changes and just by keeping the car between 55 and 65 mph, I averaged 47 mpg. The Civic is a fuel efficiency monster on the highway if you drive it right, but I'm worried that, given the Clarity PHEV's 4,000 lb curb weight, it's perhaps not very efficient at 50-65 mph, either in HV or EV mode.

    Anyway, any info people could share on this would be much appreciated. Thanks.

    [My apologies for double-posting this - the first time I posted, I meant to do so here in the Clarity sub-thread section, but I posted it in the general Honda section by accident]
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  3. jdonalds

    jdonalds Well-Known Member

    We have over 4,000 miles on our Clarity but truthfully the engine hasn't been on long, perhaps 4-5 hours max since we bought it Dec 5th. My best input to you is at 55-65 mph I'd be getting about the EPA estimate of 42 mpg.

    If you have high electricity rates would a solar system work for you? We installed solar in December just for the house, it wasn't sized to charge a car too. But after 2 months what we are seeing is our electricity bill is about 1/3 of what it was last year, and our car gas bill is nearly zero. We will be adding two more solar panels to even improve on that. By-the-way our local rate is $0.15/kWh 24/7.

    The other thing is if you take a lot of short drives during the day you may be able to recharge between drives. The car charges very quickly. Ours has never taken more than 2 hours and 5 minutes to charge from dead empty. Most of the time we don't burn through the whole battery and recharge happens in about 1 to 1 1/2 hours.
  4. loomis2

    loomis2 Well-Known Member

    I feel I should mention that jdonalds 2 hour charge time is with a level 2 charger. If you are commiting to an ev lifestyle I recommend going all in and getting one of those chargers installed. It seems like the 40-42mpg hv estimate is pretty spot on, though.
  5. ab13

    ab13 Active Member

    I would point out that lighter vehicles tend to be more efficient, but you have consider what it's like to drive and ride in different types of vehicles. If you do a lot of driving, especially on bad roads, a smooth quiet ride is much nicer than a noisy bumpy one.

    Just for basic comparison, the new 2018 Accord Hybrid is rated at 47 combined, which the Clarity is rated at 42 combined. The Accord is slightly larger, but considering about a 600-700 pound difference, this isn't too bad. The other issue is the weather and temperature conditions, this can highly affect the real electric range of the vehicle, you may find you don't have enough electric range in cold weather.
  6. KentuckyKen

    KentuckyKen Well-Known Member

    I don’t have a way to track kWh used but I can tell you that at 30-40F and with little non-motive drain on the battery I am getting over 50 miles per charge. I’ve only run the ICE in hybrid mode for one trip of about 120 miles but got 45mpg. So I’d say the EPA estimates are spot on.
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  8. Viking79

    Viking79 Well-Known Member

    The large advantage going for the Clarity is the size, if you need it. Some of the others might be a bit less costly to operate.

    However, at 75 mph we seem to get about 35 to 37 mpg in real world driving. I haven't driven enough highway to know for sure, or if you keep it at lower speeds what you will get for mpg.

    So far we have had a cold winter so I probably shouldn't comment on efficiency (it is much worse in winter), but my lifetime charging kwh (off no more than 5%, charged a few times at public chargers):
    Miles: 4774
    kwh: 1459 est $175
    Gal: 48 est $120
    cost per mile: 6 cents

    Again, this was very cold, in Dec/Jan we used 38 gallons, but in February it was much warmer and only used 6 gallons. So this is on the high side for cost per mile of what I expect to see from the car.

    PS I have reduced gas usage by about 230 gallons vs the van over the same mileage.
    Last edited: Mar 13, 2018
  9. bpratt

    bpratt Active Member

    I purchased my Clarity in late December and have only exceeded the battery once. I have a KWh meter installed in my charging circuit so I can get an accurate indication of KWh used. Here are some of my results:

    High temp in 20s 2.25 miles/KWh MPGe 75
    High temp in 30s 2.60 miles/KWh MPGe 78
    High temp in 40s 2.85 miles/KWh MPGe 85
    High temp in 50s 3.00 miles/KWh MPGe 90
    High temp in 60s 3.40 miles/KWh MPGe 102
    High temp in 70s 3.78 miles/KWh MPGe 127

    Until the high temperature reached 60s, I was using the electric heater.
  10. Kieran973

    Kieran973 New Member

    Thanks, everyone, for your responses so far.

    jdonalds, solar isn't an option for me right now because I rent my apartment. But I agree that would be objectively way better...

    bpratt, those are interesting results. Can I ask roughly how much of that is city driving vs. highway driving? And how hard were you trying (like were you hypermiling, just driving, somewhere in between?)

    I can't find it now, but I thought that someone else had posted on this thread that when they bought their Clarity, the dealer delivered it to them with an empty battery and they had a 100+ mile highway drive home in HV mode which resulted in low to mid 50's mpg. For a four thousand pound car, low-mid 50's mpg is an excellent result in my opinion. And I guess I would ask some similar questions: what temperature was it? how hard were you trying?

    KentuckyKen, 45 mpg on the highway in 30-40 degree weather is a solid result too. That means that in the summer you'd probably do at least 50 mpg on the same trip. Do you remember how fast you were going? Hypermiling vs. just driving?

    I'd be very curious to see what the results would be if you charged the battery to 100%, took the car onto a flat highway in 60 degree weather, set the cruise control to 50 mph, and drove until the battery was depleted (both in terms of the miles/kWh and EV range). The same MPG test in HV mode would be interesting too....
  11. PHEV Newbie

    PHEV Newbie Well-Known Member

    I never got the mid fifties but my best was 52 mpg. This was the average of two 200 mile loops here in PA. The weather was cloudy both days (mid 40's and 50ish) and the speeds were moderate (50-65 but mostly 50-55 mph). The car was in HV mode (Econ all the way) except for in town which was EV (subtracted all EV miles in my calculation). Passenger load about 270 lbs (I'll let you guess if that's 1 or 2 of us ;)). Cabin heater was off, seat heaters on part way. MPG based on actual fill-ups and odometer readings. I did a second click on the fill up to make sure tank was 100%. Important to note that the battery was at least 50% during HV mode.
    On a recent 1200 mile road trip with no plug-in top ups, I got 48 mpg between two of the fill-ups where I was down to about a gallon in the tank. It was warmer then (fifties all the way) but we did set the cabin heater to 62 degrees. Battery was around 50% during these two stretches and the system did maintain the battery level. I did not include our first stretch because I noticed that the battery depleted some, even in HV mode because I started with a nearly full battery (that stretch was well into the 50's mpg but used some of the battery and we were slowly descending in altitude). Another interesting thing I noticed is when we set the system to recharge mode on another stretch. It charged the battery from single digits to 28 mile range before it stopped. On that stretch, we got 38 mpg overall and it was not charging the whole time. So, although anecdotal, it seems that the miles you get from re-charge are much less efficient than staying in HV mode. That being said, I do believe that completely depleting the battery will give you less mpg than keeping a charge while in HV mode. During my HV drives, I noticed that the battery could drop by a good number of miles before they are restored by the system later. If you have a depleted battery and say you're going up a mountain, the ICE will rev like crazy to supply enough power. When I went up a significant grade, I noticed that the battery working together with the ICE to get me up the hill. After getting to the top, the battery lost a good number of miles but the ICE just hummed instead of screaming on the way up. Most of those miles were restored on system regeneration after. Again, all mpg calculations are based on odometer readings and actual fill ups (with the second click method). Econ mode (+/- HV) all the way. Speeds variable, between 50 - 70 mph.
    BTW, after the obsession with efficiency has just worn off, I noticed that making the cabin temperature comfortable has a major impact on efficiency (heating only, haven't needed AC yet). So I think the 42 mpg is accurate for fast freeway driving and HVAC on for comfort. From my experience it's not difficult to get 50 mpg if you drive like a grandmother and keep your coat on.
    iluvscuba likes this.
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  13. bpratt

    bpratt Active Member

    My driving is about 50% city and 50% highway driving. The speed limit on our freeways is 70 mph so the highway driving is all at that speed. I'm not trying to drive to conserve energy, just normal driving.
  14. Kieran973

    Kieran973 New Member

    This is all very interesting. It seems then that with a moderate amount of grandmotherish, coat-wearing effort, you could see "tank averages" in this car of 50 mpg on gas, 3.5+ miles/kWh on electricity. This is much better than I initially expected given how large this car is. Even though I've only ever owned Hondas - 3 Civics and 1 Accord - I was initially turned off when the Clarity's specs were released last year (18 inch wheels, 4,000 pounds, 102 mpge highway, etc), because this was a lot more car than I need and it seemed to indicate perhaps Toyota Avalon hybrid-level fuel economy (albeit, in PHEV form). Instead, for the last 6 months or so, the car I've been watching closely is the Ioniq PHEV. But at those efficiency levels in the Clarity, the slightly better efficiency of the Ioniq PHEV (or for that matter the Prius Prime), seems less significant: maybe $50-$100 more a year in energy costs for the Clarity, 250 more pounds of well-to-wheel CO2 from the Clarity over 15,000 miles (according to, the Clarity's well-to-wheel carbon emissions in my area are 160 g/mile as opposed to the Prime's and Ioniq PHEV's 150 g/mile). I still would like to know more, however, about how the Clarity does on the highway, particularly at low highway speeds. My work commute is 90% "highway" but at 45-50 mph, and 8-10 times a year, I make a 500-mile round-trip highway drive to see family, but always at 55-65 mph. It seems like the way to go on the highway is HV mode with a fully charged battery, then drop into EV mode the last 50 miles or so....
  15. jdonalds

    jdonalds Well-Known Member

    Estimates or reality on fuel cost, CO2, etc. all depend on your driving patterns. In our case we are pretty much driving free from our solar roof, and we rarely (and I do mean rarely) use any gas. The Clarity's 47 mile EV range is comfortable for us so the only time we have to use gas is when we leave town. So in our case a Prius Prime or Hyundai Ioniq PHEV (nice car) would actually cost more for fuel and would hit all those other spots like CO2 you mentioned. Our gas cost, for both the Clarity and our 4Runner (which we rarely drive) was $0 for January and February.

    I like the Ioniq; would have bought one had the Clarity not come along. But we would have used gas daily due to the shorter EV range.
  16. Pushmi-Pullyu

    Pushmi-Pullyu Well-Known Member

    Energy consumption (and thus kWh/mile) is highly dependent on speed. I really wish the EPA ratings would be a chart, showing consumption at 35, 45, 55, 65, 75, and perhaps 85 MPH. Using just a single number (or two, for city vs. highway driving) may be good for comparison purposes, but it's not very helpful when it comes to the energy consumption the average person can expect.

    Unless you really do normally drive 50 MPH on the freeway -- who does that? -- you'd be far better off doing your test by driving at your normal highway speed, to get a better estimate of what your personal highway kWh/mile rating would be.

    I gather from various comments you made that you are not adverse to using some hypermiling techniques, so your personal energy consumption when driving is likely lower than the average. (And congratulations on that! :) )
  17. Kieran973

    Kieran973 New Member

    Hi Pushmi-Pullyu,

    I agree that speed vs. energy consumption charts would be much better - this is in fact exactly what Wayne Gerdes does on He's done this for dozens of cars, but he's only one person and these tests are incredibly time-consuming and labor-intensive, so god bless him for even doing this much. He tends to focus on hybrids and more fuel-efficient ICE cars (as opposed to PHEV's and EV's), but here's the list of most of the cars he's tested so far:

    As for my own driving habits, I'm lucky in that all the "highways" in my area are state and county parkways with 50 MPH speed limits and just enough congestion that, when you drive at off-peak times, you can cruise along at 45-55 MPH without 1.) running into a traffic jam, or 2.) bothering people behind you who are trying to go faster. Of course, the flip side of this is that, when you do hit actual traffic (which in metropolitan areas you're bound to), the 2016 Civic's fuel economy suffers miserably. In general, the Civic's highway EPA number is drastically underrated, while it's city EPA number is over-rated. But you'd be amazed at what just driving the speed limit can do for your energy consumption, especially at low highway speeds without stop signs, traffic lights, or traffic jams - I recently clocked 64 mpg in the Civic on a 50-mile low-speed highway stretch, and I've even managed 60 mpg over 150 miles on a 55-65 MPH interstate during the summer. My lifetime tank average in the Civic right now is 25% better than EPA (45 vs. 36 mpg), and this is without any hybrid technology to help me with city driving, traffic jams, etc. So my hope for the Clarity is that, with the same driving habits, I could also average about 25% better than EPA - the Clarity does have that hybrid technology to defer the inefficiencies that the Civic would suffer in city-driving/traffic, but it's also 1300 pounds heavier than the Civic (4,000 lbs vs. the Civic's 2,700 pounds), which would drag some of the highway efficiency down. A 25% improvement on the Clarity's EPA rating would be 137.5 mpge or 4.08 miles/kWh - maybe this is overly optimistic, but even if you could do 3.5 miles/kWh, this would put the Clarity in the running to match or even beat the Ioniq PHEV and Prius Prime both in terms of energy costs and well-to-wheel C02 emissions, because the 47+ AER in the Clarity allows for many more EV miles in your total annual driving miles (at 15,000 miles a year, I could probably do 12,000 miles EV and 3,000 miles HV, whereas in the Ioniq or Prius Prime I could probably only do 9,000 miles EV and 6,000 miles HV).
  18. Kieran973

    Kieran973 New Member

    Hi jdonalds,

    I like the Ioniq too. However, what has brought me back around to the Clarity is 1.) I test drove the Ioniq and found the driver's seat to be Chevy-Bolt-level uncomfortable (really thin and firm with very little padding), 2.) according to KBB, the Clarity costs $3,000 less to own over 5 years than the Ioniq (this is due mostly to higher depreciation of the Hyundai brand vs. the Honda brand over 5 years), and 3.) while Hyundai has a better warranty than Honda on paper, my sense is that the Ioniq would be in the shop a lot more than the Clarity and you'd be constantly dealing with the Hyundai service department, not to mention having your car off the road for more stretches of time....
  19. Kieran973

    Kieran973 New Member

    On the other hand, just to be fair to the Ioniq, it's more efficient, it has the added utility of the hatch, I do think it looks better than the Clarity, and with the tax credits/rebates and dealer discounts, you can pick one up in many states for $18-19K even after tax....
  20. ResilientMtl

    ResilientMtl New Member

    Hello, I am Clarity owner and live in Quebec (cheap electricity, expensive gasoline). Hydro Quebec is owned by the government and they want to push electric vehicles. The government put together a brochure ( ) which outlines the various options. It is in French, but they list the vehicles at the end with pictograms and specifications in numbers. They list the Clarity electric efficiency at 18.7 kWh/100 km, the Volt at 19.9, the Prius Prime at 15.8 and the Ionique Electric at 15.5 kWh/100km and the Bolt at 17.6 kWh/100 km. Important to consider, the Clarity is BIG. It is roomier than any of the other cars listed. It has almost double the all electric range of the Prius Prime (more battery, heavier car). It has lots of trunk space and the interior is quiet and nice to be in. I can't charge the Clarity more than 15.4 kWh, so the car is holding 1.6 kWh in reserve. Based on the numbers listed, given the Prius Prime's battery size (8.8 kWh) and claimed range (40 km/25 miles) vs. the Clarity numbers (76km/47 miles) it looks like the Prius holds much more battery in reserve to help reduce the gasoline being burned in hybrid mode. On a long trip, with few charges, the Prius should burn less gas; but you can't carry as much cargo or people.
    The spread between electricity and gasoline in Quebec is huge. A 15 kWh charge is $1.35 CAD and 80 km of fuel at 5.3 L/100 km (103 kph /64 mph cruising) is $6.14 CAD ($1.45 CAD/liter). So you're saving around $4.79 per charge if you drive 80 km (draining the battery). If my Clarity was as efficient as a Prius Prime, I would get about 20% more range (and savings). But the Prius Prime doesn't have the range of the Clarity. So if you drive 80 km, the Clarity is more cost effective due to the size of the battery. If you just want a commuter car, and won't push the range then get an Ionique (200 km / 120 miles) which gives you efficiency and good range; but not the limitless gasoline range or the space of a Clarity. The best thing about the Clarity is that you don't have to compromise. 5 seats, lot's of cargo space, familiar interior, good electric range, good fuel efficiency. If you only have one car and a family of 5; it makes sense.
  21. Viking79

    Viking79 Well-Known Member

    The Ioniq PHEV looks like a great car, but I want to point out for those living in cold climates that Hyundai/Kia don't use electric heat with their PHEVs, they rely on gas heat, so even in mild temperatures they will start the engine if heat is required. That is like half the year where I live instead of the couple weeks the Clarity runs the engine for heat (mostly on sub 0 F days).
  22. Dreamgt

    Dreamgt New Member

    Hello everyone,

    Adding my .02 cents for "real-world driving efficiency": I just got my Clarity on Saturday June 2nd 2018 and have driven it every single day since then. I have put 584 mi. on the odometer and still have have 1/2 a talk of gas & 150 mi. range in HV mode. I charge it at home, overnight, and also at work on Level 2 ChargePoint's.

    • Distance between my home and job is about 60 miles. (120 mi. total round trip)
    • Work elevation is at 819.05 ft above sea level.
    • Home elevation is at 2724.8 ft above sea level.

    Driving to work is almost all down hill, with a difference of 1905.75 ft from the high desert to the valley, I can make it to work in 100% EV mode, ECO enabled. By the time I get to work I have traveled an average of 58 miles, but still have around 10 mi. of battery power, completely blowing the EPA estimate out of the water.

    Driving home is an uphill battle, but in traffic a lot of the times which improves the battery efficiency. I usually run out of battery power and enter HV mode during the last 12-15 miles of my commute, which closely reflects the EPA estimate for the battery power alone, even traveling on a highway, at variable highway speeds, with stop-n-go traffic, uphill (1905.75 ft).

    My commute is a mix of 40% back-roads, 40% freeway, and 20% city.

    So far I've saved around $80 that I would have easily spent this week in gas, and I think I'll be making it to the 800 mi - 900 mi range before having to fill up, saving me around $347 a month, which covers my lease payment and some insurance. The car, in less than a week is already showing me it pays for itself, and keeps money in my pocket; I really enjoy driving it too! Sport mode is punchy and fun, especially at the freeway entry ramp traffic lights (mini-drag race ramps), a lot of cars have trouble keeping up with the instant torque off the line. And all this is coming from a guy who usually commutes in a 2016, 330 HP Volkswagen GTI.

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