Longer Term Reliability?

[JeffJo]

Up until I bought my 67 hp (73 hp with IMA motor) 2000 Honda Insight the Society of Automotive Engineers (SAE) defined how to calculate horsepower.

You really are determined to not understand this, aren't you?

"Horsepower" is a defined unit in Physics. SAE has nothing to do with it, only James Watt.

SAE defines how to measure the horsepower of an engine. Not a car, an engine. Since both that 2000 Insight and the Clarity have a battery, their measurement is not the complete story.

Maybe because it was a parallel hybrid, Honda didn't need to come up with their own way to define total horsepower.

Didja notice that it was actually "67 SAE net HP" and "73 with IMA" ? The 73 is "their own way" that Honda came up with, although it was much easier.

So the Clarity PHEV could have produced more horsepower but Honda chose to limit the "output" to 212 hp?

You still don't get it? The choice was to put in a 181 HP traction motor. Then the designers had to power sources that were sufficient to supply it, and the rest of the car, with electricity. That's 181 plus something on the order of 31 HP. My point there was that WE DON'T KNOW EXACTLY HOW MUCH THAT IS. But Honda wants informed owners, so they publish a number that is most comparable with the SAE net published for other cars.

 

[insightman]

You really are determined to not understand this, aren't you?

"Horsepower" is a defined unit in Physics. SAE has nothing to do with it, only James Watt.

SAE defines how to measure the horsepower of an engine. Not a car, an engine. Since both that 2000 Insight and the Clarity have a battery, their measurement is not the complete story.


Didja notice that it was actually "67 SAE net HP" and "73 with IMA" ? The 73 is "their own way" that Honda came up with, although it was much easier.


You still don't get it? The choice was to put in a 181 HP traction motor. Then the designers had to power sources that were sufficient to supply it, and the rest of the car, with electricity. That's 181 plus something on the order of 31 HP. My point there was that WE DON'T KNOW EXACTLY HOW MUCH THAT IS. But Honda wants informed owners, so they publish a number that is most comparable with the SAE net published for other cars.

Thank you for your efforts. I am not trying to be confrontational. I realize you are trying to get through my thick skull, but it would be much easier for me if Honda had stuck with their original way of describing hybrid-car horsepower. However, I fully accept your last sentence explaining that Honda was trying to come up with a number comparable with the SAE net published for other [ICE, I assume] cars. I apologize for the exasperation and consternation I caused.

 

[Frankwell]

You really are determined to not understand this, aren't you?

You still don't get it?

They seem to have inadvertently created a bit of a dilemma for themselves with the traditional method. In the document that Ray B linked to in post #41 it says:

"The vehicle power rating has customarily been the same as the rated power of
the engine, as determined by an engine bench test. This is a convenient way
to assign a power rating to a vehicle, because the engine power rating may
then be applied to any vehicle that uses the same engine."

The key word being convenience. But convenient for whom? I'm sure engineers prefer the viewpoint of engine benchmark power rating. The consumer maybe not so much as they are mostly interested in what power is being delivered to the wheels. However in the past this was not really an issue since drivetrain losses will probably be similar between vehicles, so the horsepower rating provides a useful comparison. As pointed out in the document:

"As a measure of real-world vehicle performance, this traditional
measure is imperfect, since it does not account for the power lost in the
drivetrain between the engine and the road. However, it has become well
established and is generally accepted as a useful metric, in part because
conventional vehicles have only one engine, and its full rated power is
typically available"

But the usefulness of the traditional approach starts to diminish when two propulsion methods are involved.

"While it may seem that this would simply be the
sum of the rated power of each component, this is not necessarily valid in
practice. It will result in an overestimate if, for example, the electric machine
is limited by the available battery power, or if the control system limits or
reassigns some of the nominal capacity, such as to maintain traction or charge
the battery."

The ideal solution would be a changeover to a dynamometer system for all cars, basing the horsepower rating on the power output at the wheels since that is what most people actually care about. However they decided against this approach as this would essentially render as useless the previous ratings using the traditional method. So they apparently decided that:

"a power rating for electrified vehicles should be qualitatively and quantitatively
compatible with the traditional engine-based power ratings of conventional
vehicles. "

To do this for hybrids and electrics they use some complicated calculations and methods. In the end achieving the goal of being compatible with the traditional method, rather than accepting a change in scale as happened with for example tornado and earthquake ratings. I'm sure they had many valid reasons for not changing methods, as that would affect a wide range of regulatory and other processes. I'm not arguing against it, just pointing out that this seems to be what was decided and why.

In the end it's just one metric. After all what the consumer is really interested in is how "fast" the car will go, and horsepower alone doesn't tell that story. The same engine can be put in a car twice the weight as another, in which case it will not seem as powerful to the driver. That's why there are other measurements that people look at like 0-60 times.

 

[JeffJo]

Thank you for your efforts. I am not trying to be confrontational. I realize you are trying to get through my thick skull, but it would be much easier for me if Honda had stuck with their original way of describing hybrid-car horsepower.

It would be more helpful if you would accept that the 212 HP figure is "sticking with the original way." That way is now, and always has been, an incomplete description. It means the power that the car can extract from fuel and/or battery. The problem is that this is now, and (again) always has been, determined before that power is divided between various systems, and before it is subjected to various losses.

The 181 HP figure, which has nothing whatsoever to do with extracting power, is the more descriptive and useful figure. Because it describes only what can be applied to the road, after power is divided and after almost all of the possible losses. And it represents a quantity you have never been told about before; definitely not "the original way."

All the 85% estimation I've described is about, is Honda say "Yes, we can extract enough power to fully provide for this more useful number, in addition to those other sources and losses. But if you want a number that compares to 'the original way', it is 212 HP."

 

[Landshark]

I accept that the 181hp electric motor can produce 212hp for brief periods of time from the current, provided simultaneously, from both the battery and generator. This liberates me to waste my time on more important matters.

 

[JeffJo]

I accept that the 181hp electric motor can produce 212hp for brief periods of time from the current, provided simultaneously, from both the battery and generator. This liberates me to waste my time on more important matters.

No, the electric motor is rated at 181 HP, and that is hard limit. I don't know whether it is the maximum input, or the maximum output, but it never exceeds it.

I think I figured out what makes this hard to understand. The analogy for the electric motor is not the ICE in and ICEV. It is the transmission. An engine produces power from a stored source of energy. Both a transmission, and an electric motor, transform that power in some way and transmit it to another device.

So in an ICEV, the ICE produces power from gasoline, in the form of a rotating shaft at some RPM. It is the battery, and its controlling electronics, that "produce" the electricity in a BEV. The ICEV's transmission transforms the ICE's RPM into that of the wheels, and transmits most (but not all) of this power to them. In a BEV, the traction motor turns most of this power into mechanical power, and transmits it to the wheels. Here is a simplified diagram:


In the conventional car, the only power figure we know is the maximum output of the ICE. It is called SAE Net Horsepower. The estimates that I have seen say that 85% of that can reach the wheels, but that is only an estimate. In truth, we don't know what it is.

In the BEV, the only number I have seen published is the motor's rating. This is probably because the Battery Control and Power Control are really parts of the same overall device, so there really is no point where the amount of power tat is actually "produced" can be measured. So I'm treating it as analogous to the output of the motor here, mostly because it makes the three diagrams line up nicely.

In the Honda iMMD hybrid, we know the motor's rating the same way we know it for a BEV. But this is not power being produced, it is the portion of the power produced by the battery and the ICE that reaches the motor. And again, Battery Control and Power Control are the same device. So again, there is no point where this power can be can be measured. But, if the peripherals and losses are comparable to those in an ICEV, then we can estimate the maximum combined power we need by (Combined Power) = (Motor Rated Power)/0.85.

This does not mean the two sources are limited to this number, any more than a BEV's battery is limited to the power that its battery and peripherals can take. It means that the system is capable of that much. This is why the Accord and Clarity have the same combined power.

 

[Landshark]

No, the electric motor is rated at 181 HP, and that is hard limit. I don't know whether it is the maximum input, or the maximum output, but it never exceeds it.

How did you reach this conclusion?

So again, there is no point where this power can be can be measured. But, if the peripherals and losses are comparable to those in an ICEV, then we can estimate the maximum combined power we need by (Combined Power) = (Motor Rated Power)/0.85.

I’m sticking with my statement, as there’s less speculation involved than anything else that’s been presented.

 

[Frankwell]

I think I figured out what makes this hard to understand.

Comparisons between ICE, EV, and hybrid are inherently problematic and I don't think your definition settles the question, although it is an interesting viewpoint.

Both a transmission, and an electric motor, transform that power in some way and transmit it to another device.

I would say that I don't agree with comparing the traction motor with the transmission in an ICE vehicle. A transmission does not transform energy, a transmission transfers energy.

Fuel squirted into a cylinder contains chemical energy. The fuel is combusted, the resulting gas pressure accelerates the piston, with a resulting increase in the kinetic energy of the piston. Thus we can say that the chemical energy, or at least some of it, has been transformed into kinetic energy inside the cylinder. In an ICE car that kinetic energy is then transferred from one part to another, eventually ending up at the wheels. The kinetic energy of the piston is transferred first to the piston rods, then to the crankshaft, then to gears in the transmission, then to the driveshaft or transaxle, then to the wheels. The rotation of the wheels transfers the kinetic energy to the entire car causing it to accelerate.

Looking at it in reverse, the kinetic energy of the wheels can be traced directly back to the kinetic energy that was produced inside the cylinder, with no transformations in between, only transfers of existing kinetic energy. So we would say that the engine, specifically the piston inside of the cylinder, is where the power is produced. Although for convenience the power is usually measured at the crankshaft.

In an EV, chemical energy in the battery is transformed into electrical energy and sent to the traction motor where it is transformed into kinetic energy. This kinetic energy is then transferred from one part to another with no further transformations until it reaches the wheels. Obviously a smaller number of parts are involved compared to ICE, but the concept is similar, the kinetic energy of the wheels can be traced directly back to the kinetic energy that was produced inside the traction motor. Comparisons with an ICE vehicle are difficult however because although in this viewpoint we would say that the traction motor is where the power is produced, the more common viewpoint is that the battery is the source of the power, even though the kinetic energy cannot be traced directly back to the battery. And it would also not technically be the correct use of the word power as it is defined in physics, although in these type of discussions a more general use of the word power is usually accepted as a way to communicate the broader concepts.

In a series hybrid like the Clarity there is an additional energy transformation when ICE provides power to the wheels. I don't include direct drive mode because it is never used at maximum power, which is what power ratings are generally about. There is the initial transformation of chemical energy into kinetic energy inside the cylinder. The crankshaft spins the generator where the kinetic energy is transformed into electrical energy. This electrical energy is then sent to the traction motor where it is converted to kinetic energy, and then transferred via various parts to the wheels. Thus in HV mode we again have a difficult comparison, because you could say that the kinetic energy driving the wheels can be directly traced back to the traction motor, thus the traction motor is the source of power for the wheels. However again the more common viewpoint would be that the engine is the source of power.

When ICE and the battery both supply energy at the same time, we could say that the traction motor remains as the source of power for the wheels. However once again the common viewpoint would be that the engine and the battery are the sources of power. Complicating things even more is that the traction motor can be a limiter depending on its capability. If a powerful enough traction motor is used there would not be a limit, the maximum power to the wheels would be the combined maximum power of ICE and the battery. However when a less powerful electric motor is used then this reduces the total amount of power available to the wheels, in this case making the traction motor the definer of total power.

 

[JeffJo]

I’m sticking with my statement, as there’s less speculation involved than anything else that’s been presented.

????

That is complete speculation. There is absolutely no evidence that the motor can handle more than 181 P. But then, you probably have not seen the quote from Takeshi Wakamatsu, a head engineer at Honda and lead author of the paper "Development of 2.0 L Engine for the New Accord Hybrid." He said "only 181 HP can come from the traction motor." That seems pretty definitive.

Comparisons between ICE, EV, and hybrid are inherently problematic.

That's why I said the diagrams were simplified, and made it clear which numbers were estimates.

I would say that I don't agree with comparing the traction motor with the transmission in an ICE vehicle. A transmission does not transform energy, a transmission transfers energy.

It transforms, say, 100 lb-ft at 5000 rpm to 500 lb-ft at 1000 rpm. But the point is that neither the transmission, not the traction motor, is "producing" power. Both require an input source of power, which becomes output with some kind of a difference in form.

Here's a step-by-step, generic description:

1. The car has reservoir, where a substance with chemical, potential energy is stored.
2. There is a device that I'll call the power plant that releases this energy, and creates a flow of energy that is called power.
   1. Some gets used for purposes other than propulsion.
3. There is a second device that I'll call the transformer that alters the leftover power into the form used by the wheels; that is, a torque at the RPM of the wheels.

The "power produced" is the power created in step #2. The "propulsion power" is taken from step #3, RPM*Torque*conversion_factor.

• In an ICEV, the maximum "power produced" is measureable quantity, called SAE Net Horsepower. Maximum "propulsion power" is not known, because it depends on the efficiency of the transformer and parasitic draws for peripherals.
• In an EV, the maximum "propulsion power" (or something very close to it) is determined by the rating of the motor. There is no evidence that this rating is exceeded.
  • In a BEV, one would expect that the battery system is capable of providing this power, plus whatever is needed for peripherals, and any losses.
  • In a serial HEV, it is the generator and battery combined.

 

[Frankwell]

There is a second device that I'll call the transformer that alters the leftover power into the form used by the wheels; that is, a torque at the RPM of the wheels.

I'm guessing that you are talking about the transmission again? If so I would not say that the transmission alters the power into the form used by the wheels. However next to it are some parts that do, the piston rods and the crankshaft. They convert the pistons' linear kinetic energy, which is unusable by the wheels, into the rotational kinetic energy that the wheels need. The car would be undriveable without this alteration of the power by the piston rods and crankshaft.

Yes the transmission alters the power also, by altering the gear ratio within a range of high power/low speed to low power/high speed. However this is more about efficiency and drivability, as an ICE vehicle can in theory operate with just one gear ratio, although it would not be very efficient or enjoyable to drive. So by all means the transmission is important, but if we are going to pick one section of the drivetrain as being the place where the power is altered into the form used by the wheels, I nominate the piston rods and crankshaft.

In the case of an EV or serial hybrid, the kinetic energy produced by the traction motor is already rotational, so it doesn't need to be altered. In fact it also doesn't need any alterations to the gear ratio to be efficient or drivable, which is why EV's don't have a transmission in the traditional sense, not even a CVT. Honda calls the Clarity "transmission" an eCVT, which is a name apparently designed to sound somewhat familiar to the typical car buyer, even if technically the name doesn't really make any sense.

Some exceptions - the Porsche Taycan has a two-speed gearbox for increased acceleration and higher top end speed. And interestingly Kia and Hyundai PHEV's run all of the power through a six-speed automatic transmission even while driving in EV mode.

 

[JeffJo]

I'm guessing that you are talking about the transmission again? If so I would not say that the transmission alters the power into the form used by the wheels.

This is just a matter of semantics, and you seem to be taking a far-too argumentative stance about it. I choose to call a change from 200 lb-ft at 1000 rpm, to 100 lb-ft at 2000 rpm, an alteration of the form of power. I choose to do so only to create a placeholder in the analogy, for something that does exist in the EV. Even though it is not necessary for the analogy.

You don't choose to do so. That's fine. The traction motor in an EV still fulfills the same primary function as the transmission in an ICEV. Neither "produces" power. They take, as an input, the power that is produced (A) by another device (B) from stored chemical energy (not power), (C) massage it into the correct form power as it can be used by the wheels, and (D) pass it along the the wheels.

The point being that the capabilities of neither the transmission, nor the traction motor, have anything directly to do with the power that a car can "produce." But they have everything to do with what power can be passed to the wheels.

In an ICEV, it is the engine that "produces" power from gasoline. This power stream gets split, so that some can be used by peripherals. What's left becomes the input to the transmission, where the rpm of the engine is to be changed to the rpm of the wheels (with P_OUT=EFF*P_IN). The maximum power that can reach the wheels is, simplistically, the power produced by the engine, minus the power pulled off for peripherals, minus the losses in the propulsion path.

The issue here is that only the engine's power is published. All the other numbers are estimates. One I have seen used is (Max Propulsion Power)=0.85*(Max Produced Power).​

In a BEV, it is the battery (and controlling electronics) that "produces" power from lithium ions. This power stream gets split, so that some can be used by peripherals. What's left becomes the input to the traction motor, where the electric power is changed into (torque)*(rpm of the wheels). The maximum power that can reach the wheels is, simplistically, the power rating of the traction motor. But to get that, it needs the battery (and controlling electronics) to produce this power, plus the losses in the propulsion path, plus what gets pulled off for peripherals.

The issue here is that (AFAIK) only the motor's rating is published. Any other numbers would be estimates.​

ICEVs publish only the power that the ICE can produce, because they can't know the missing details. A Tesla Model 3, single motor, is rated at 211 kW. That's the motor's rating. I don't know if they publish the battery's capability. You might be able to find it, but it would be unethical to publish it as a rating for the car, since the car can't use it all at a time. But to use that motor to its full capability, the battery needs to be capable of producing something like 250 kW, so that 39 can be budgeted for peripherals and losses. That's probably a little pessimistic. But you know what? I don't care. This is only a mental exercise. And I'm sure that a Tesla's battery can produce much more if they are taken out of the car. But in the car, they will only produce what the car can use.

Honda publishes both numbers for iMMD hybrids. The 181 HP is the Accord's and Clarity's traction motor's rating, and it is not ever exceeded. In order for the battery+generator to be able to supply that 181 HP, it needs to produce a little bit more so that some can be pulled off for peripherals, and to account for losses. It isn't an exact number, but the spec is 212 HP since that uses the same estimated numbers that an ICEV uses. But this is a spec - the system needs to be able to produce that much. Honda publishes it only because it provides the best comparison to the power of an ICEV.

 

[Frankwell]

This is just a matter of semantics, and you seem to be taking a far-too argumentative stance about it.

Perhaps you think that I am arguing that my viewpoint is the correct way to compare ICE to hybrid power production. My actual argument was made in post #68 when I said:

"Comparisons between ICE, EV, and hybrid are inherently problematic."

In that statement and several others in my posts I have attempted to demonstrate that the differences between ICE and hybrid power production are so fundamentally different, that comparisons will inevitably be incomplete because of the lack of common ground. Commonality can be demonstrated in one frame of reference, but is then lost when viewing the situation from a different angle. You seem to believe that it is possible to come up with a "grand unifying theory" (as they call it in particle physics) to unite ICE and hybrid conceptually. Whereas in my opinion ICE and hybrid are the classic example of apples to oranges.

Even a simpler comparison of ICE to EV is difficult. On the surface they seem similar, after all we put "fuel" into each vehicle, and power is produced from that fuel to move the car. In that viewpoint the fuel tank and the battery are equivalent, these are the places where chemical energy is stored. The gas engine and the electric motor are where the power is produced. But in a more detailed look at the transformation and transfers of energy that take place in each type of vehicle, it is not quite as clear. For example we normally see a battery as having a more involved role in the production of power than a gas tank does. Meanwhile hybrids take the complexity to yet another level with their multiple interacting transformations and transfers of chemical, electric, and kinetic energy.

You also seem to have the opinion that applying classic SAE horsepower calculations to a total hybrid system is quite sensible. I think your opinion is a valid one in some ways, but there are other valid viewpoints on that topic. But you were quite hard on someone who didn't agree with your viewpoint, to the point of making several insulting statements questioning their capability for comprehension if they didn't see things your way.

The one detailed sub-topic that I have argued about is the role of the transmission in the apples to oranges comparison. I attempted to lay it out using the more traditional definitions for energy transfer and transformation than you are using. Not as a way to argue semantics, but again as a way to demonstrate that there is more than one valid viewpoint on this topic.

 

[Landshark]

That is complete speculation. There is absolutely no evidence that the motor can handle more than 181 P. But then, you probably have not seen the quote from Takeshi Wakamatsu, a head engineer at Honda and lead author of the paper "Development of 2.0 L Engine for the New Accord Hybrid." He said "only 181 HP can come from the traction motor." That seems pretty definitive.

The 181hp rating is for continuous duty. An electric motor can “handle” an additional ~15% for brief periods of time. Add 15% to 181.

The engineers statement seems definitive, yet he’s offers no explanation. Your explanations are littered with too many ifs and buts. That’s speculation in my book.

 

[JeffJo]

Perhaps you think that I am arguing that my viewpoint is the correct way to compare ICE to hybrid power production. My actual argument was made in post #68 when I said:

"Comparisons between ICE, EV, and hybrid are inherently problematic."

Yet you keep proffering other arguments.

Mine is that:

1. The 181 HP number is the rating of the traction motor.
2. The 212 HP number means the maximum combined electrical horsepower of the ICE-driven generator, and the battery.
3. The reason for the 212 HP number is not because they can't produce more - we don't know. It is not an estimate of what the motor might be able to do if over-driven. It is because that is the best possible estimate that compares to the HP rating of a gas car, given the problematic nature of comparing different kinds of systems.

I recognize that this comparison is incomplete. One of the ways you didn't mention, that seems more important to me, is this: A gas car's HP rating can only ever apply at one RPM, and that RPM depends on car speed and transmission setting. So in practice it will very seldom, if ever, be achievable. The 181 HP of the traction motor (or whatever over-driven limit you think applies) - can be achieved anytime the electric motor exceeds about 4100 RPM (or whatever you think HP_MAX*5252/TORQUE_MAX is). For as long as the system can supply that much.

You also seem to have the opinion that applying classic SAE horsepower calculations to a total hybrid system is quite sensible.

Where did I say anything like that? I only said that, in this analogy - which is problematic but seems to be what Honda engineers use - the 212 combined power fills the same niche that SAE Net horsepower does for pure ICE cars. The maximum rate at which energy can be extracted from stored form, for the use of everything in the car that needs it.

 

[Frankwell]

I only said that, in this analogy - which is problematic but seems to be what Honda engineers use - the 212 combined power fills the same niche that SAE Net horsepower does for pure ICE cars.

I somewhat agree with what they did with the HP rating, or at least I can understand the reasons why as they had limited choices. Unless they were willing to upend the whole process which was probably not realistic, at least not now, maybe in a few years when nearly all new vehicles are either EV or hybrid.

It does fill the niche in some ways, but will inevitably create some confusion. With ICE cars there was just the one number which is the HP rating, and it was pretty clear to most people what it represented. Even if someone didn't understand that the full amount of horsepower would not be going to the wheels, it's still a fairly accurate comparison of different engine power between vehicles. If one car has an engine that is rated at 25% more horsepower than another car, then roughly speaking that car will have approximately 25% more power available at the wheels, which is what people want to know.

The combined power rating for hybrids is also relatively useful as a way to compare vehicles, but the consumer is hit with several different numbers, engine HP, traction motor HP, and combined HP. The correlation between these is not obvious, leading to confusion about where the numbers are coming from. Some of this confusion is inevitable, but perhaps if the car makers gave some explanations about how the numbers are derived, i.e. answering some of the questions that we are discussing in this thread, that would help. Not that I really expect that to happen.

 

[David Towle]

I'm staying out of this discussion, but note the new Civic Hybrid to replace the Insight shows now 2 drive motors but still the same 181 hp, and the 2.0 liter engine like from the Accord Hybrid. I would guess the 1.5 liter was inadequate at times with the small battery reserve of the Insight. https://www.motor1.com/news/580067/honda-insight-dead-civic-hybrid/

 

[insightman]

I'm staying out of this discussion, but note the new Civic Hybrid to replace the Insight shows now 2 drive motors but still the same 181 hp, and the 2.0 liter engine like from the Accord Hybrid. I would guess the 1.5 liter was inadequate at times with the small battery reserve of the Insight. https://www.motor1.com/news/580067/honda-insight-dead-civic-hybrid/

Then, of course, following Honda's rule 181/212 rule, the new Civic i-MMD hybrid will be specified to have a total of 212 hp, regardless of engine horsepower. It will be interesting to see if it can match the gen-3 Insight's fuel economy.

 

[Frankwell]

Then, of course, following Honda's rule 181/212 rule, the new Civic i-MMD hybrid will be specified to have a total of 212 hp, regardless of engine horsepower.

I expect it probably will. In a previous thread jeffjo gave some examples:

2014-15 Accord PHEV.
166 HP traction motor, combined 196 HP

2017+ Accord Hybrid, CR-V Hybrid, Clarity
181 HP traction motor, combined 212 HP

2019+ Insight
129 HP traction motor, Combined 151 HP

In all of the above cases the traction motor is almost exactly 85% of the listed combined horsepower.

Myself and others have argued with jeffjo on other points, but this particular nugget that he shared in a previous thread brought a lot of insight, clarity, or whatever other pun someone wants to use into this subject.

 

[Casey Martin]

I haven't read this entire thread but I figured I would post my long term ownership results. I have a 2018 Clarity with over 82,000 miles now. The only real issues I have had were the Sirius XM tuner and the gas/fuel door. The Sirius XM tuner had a very strange issue since the car was new. I had posted about it here but long story short after replacing the Sirius XM tuner the 2nd time I had no more issues. It was a very frustrating and unusual issue but it was corrected. The fuel door, gas, randomly started popping open while driving for no apparent reason. I believe Honda replaced the gas door opener or latch to correct the issue. Not sure when that happened but it was after the 3 year/36,000 mile warranty had expired. I had purchased the Honda Care 6 yr/120,000 mile warranty when I got the car because I drive over 20k miles a year. Regardless what ever they replaced fixed the gas door issue.

I also had an issue with the front rotors warping. That is totally expected since I drive it hard and warping Honda brake rotors is fairly easy to do with spirited driving. I decided to replace the front rotors with an aftermarket set instead of cutting the stock ones. That corrected the issue and I reused the stock pads since there was plenty of meat left. I have not had an issue of warped rotors since I replaced them about 10k miles ago. I am sure I will warp them again but I expect that. I have worked for Honda for over 25 years and I have warped the rotors on every Honda I have ever owned. I take ownership in that since I do drive aggressively. If you drive conservatively this may not be an issue for you.
Besides that I have had zero issues with my Clarity. I have changed the transmission fluid a couple times already. I recommend doing that every 30k miles or so since it doesn't hold a lot of fluid. It is fairly easy to do yourself so do it. I have changed the cabin and engine air filters which obviously are easy to change.

My biggest complaint with the Clarity is the horrendous wipers and the lack luster performance in the winter. I live in RI and I install snow tires between November and April. The car can handle snow just fine with snow tires installed but the battery performance is terrible below freezing. I expected that and can live with it but the Clarity is really terrible for long commutes in below freezing temps. It is serviceable and gets me where I need to go but the performance is terrible compared to above freezing temps. I tell people I love the Clarity for 8 months of the year and I accept it the other 4.

I hope this helps someone. I will be sure to post my results as the mileage adds up. As of now I am planning on keeping it for the long haul. Time will tell.

 

[megreyhair]

I haven't read this entire thread but I figured I would post my long term ownership results. I have a 2018 Clarity with over 82,000 miles now. The only real issues I have had were the Sirius XM tuner and the gas/fuel door. The Sirius XM tuner had a very strange issue since the car was new. I had posted about it here but long story short after replacing the Sirius XM tuner the 2nd time I had no more issues. It was a very frustrating and unusual issue but it was corrected. The fuel door, gas, randomly started popping open while driving for no apparent reason. I believe Honda replaced the gas door opener or latch to correct the issue. Not sure when that happened but it was after the 3 year/36,000 mile warranty had expired. I had purchased the Honda Care 6 yr/120,000 mile warranty when I got the car because I drive over 20k miles a year. Regardless what ever they replaced fixed the gas door issue.

I also had an issue with the front rotors warping. That is totally expected since I drive it hard and warping Honda brake rotors is fairly easy to do with spirited driving. I decided to replace the front rotors with an aftermarket set instead of cutting the stock ones. That corrected the issue and I reused the stock pads since there was plenty of meat left. I have not had an issue of warped rotors since I replaced them about 10k miles ago. I am sure I will warp them again but I expect that. I have worked for Honda for over 25 years and I have warped the rotors on every Honda I have ever owned. I take ownership in that since I do drive aggressively. If you drive conservatively this may not be an issue for you.
Besides that I have had zero issues with my Clarity. I have changed the transmission fluid a couple times already. I recommend doing that every 30k miles or so since it doesn't hold a lot of fluid. It is fairly easy to do yourself so do it. I have changed the cabin and engine air filters which obviously are easy to change.

My biggest complaint with the Clarity is the horrendous wipers and the lack luster performance in the winter. I live in RI and I install snow tires between November and April. The car can handle snow just fine with snow tires installed but the battery performance is terrible below freezing. I expected that and can live with it but the Clarity is really terrible for long commutes in below freezing temps. It is serviceable and gets me where I need to go but the performance is terrible compared to above freezing temps. I tell people I love the Clarity for 8 months of the year and I accept it the other 4.

I hope this helps someone. I will be sure to post my results as the mileage adds up. As of now I am planning on keeping it for the long haul. Time will tell.

@Casey Martin , did you feel the brake pedal vibrating when you stepped on the brake? The reason I asked is because I don't think the pedal connects to the master brake cylinder like ICE cars do. So wondering how the pulsating effect get transferred to the pedal.