Wrong HV range

[vicw]

UPDATE - after a round trip to New Orleans (1629 miles) my HV range came down to 280 miles +/- 15 miles per fill up. That was after the first 2-3 refills, and I would guess 95% HV mode only. I did forget at least three times to set in HV mode and started off down the interstate at 75 mph just to look up in horror and see there was less than 10 miles EV range left - I think I could hear the electrons whistling out of the batteries at plus-70 mph - so then I'd run in HV Charge mode for an hour or more to get it back up to plus 20 miles EV range - not sure that is a good trade off frankly.

That is reassuring. Good to know that the reported HV range will probably go back down toward reality over time. I have a theory that Honda might be calculating HV mileage, based on the total miles driven, divided by the actual gas usage since the last fill up, and gets a bogus result until sufficient HV driving has been done to get a decent usage reading after the last fill up. Maybe that isn't exactly right, but something like that which skews the result way out of reality. I think it's incredible that with all of the technical engineering expertise that Honda has, they put out something as elegant as the Clarity with this basic and obvious flaw. Reminds me of the Hubble telescope lens that was discovered to be badly out of focus after launch and orbiting the earth, due to a small and obvious miscalculation.

I hope Honda gets it fixed, but actually, it has no real impact on my driving. I can get a pretty good idea of the remaining mileage from the segment display, which, as far as I can tell, is more or less realistic.

Regarding running the batteries completely dry - I believe that while I was driving in EV mode, it never went below about 10% (2 segments). It seemed to automatically switch to HV mode, and maintain that level. It was all very transparent, and good to know that I didn't have to worry about completely exhausting the battery.

 

[bobcubsfan]

Looking at the bars in the fuel gauge, how can one tell how much gas is left in the tank? HV range says it is 227. Started with 294, so went down 67 miles. That translates to 1.6 gallons at 42 mpg. Seems off HV bars are about 2 above middle.

 

[vicw]

Looking at the bars in the fuel gauge, how can one tell how much gas is left in the tank? HV range says it is 227. Started with 294, so went down 67 miles. That translates to 1.6 gallons at 42 mpg. Seems off HV bars are about 2 above middle.

I can't attest to the absolute level of accuracy of the bars, but as others and myself are reporting, the HV Range display can be grossly inaccurate. Mine has been showing 999 miles for the last few weeks, or so, since I added 2 gallons of gas to top off the tank.

Until Honda resolves that crazy HV Range problem, I have at least some faith that the bars are giving a more or less reasonable approximation of how much gas remains in the tank, and the reported EV Range is reasonably accurate. I try not to let the gas level get down much below 1/2 full (my wife won't let me.) I have the luxury of charging almost every night, and our normal daily driving is below 40 miles a day 99% of the time.

 

[dstrauss]

Looking at the bars in the fuel gauge, how can one tell how much gas is left in the tank? HV range says it is 227. Started with 294, so went down 67 miles. That translates to 1.6 gallons at 42 mpg. Seems off HV bars are about 2 above middle.

I have found the bars to be close to accurate - say within 10% +/-; a few times I've added 4 gallons at or slightly above half-full, which would give you pause. The best solution, for now, is set the trip odometer when you refill, and start looking for gas after 200 miles - on my lowest mpg that gave me about 40 miles range (35 mpg) and at the upper end maybe 80 miles range (at 41 mpg). Plus if you start out with a full battery you can probably get another 25-30 miles (+/-) at freeway speed on the battery.

That's why I feel the next model has to be pushing 70 miles on EV or stretch another 3 gallons into that tank.

 

[KentuckyKen]

I too have found the EV range to be very accurate. It always tracks with in a mile or two of the odometer reading. I’ll say one mile since odo doesn’t have tenths.

As everyone is reporting (or will after their first fill up), the HV range calculation is wildly inflated. The only instance where it returns to anything approaching normal seems to be when all or almost all of your recent trips are in HV mode. So I agree with the supposition that it may be calculating based on total mileage and doesn’t separate out the HV miles.

Another WAG would be that maybe they just ported over the same software calculation from the FC and BEV Claritys which only have one mode. In any case the engineer that let this car go into production with such a glaring (and easily remedied) software error was grossly overpaid.

 

[bobcubsfan]

I too have found the EV range to be very accurate. It always tracks with in a mile or two of the odometer reading. I’ll say one mile since odo doesn’t have tenths.

As everyone is reporting (or will after their first fill up), the HV range calculation is wildly inflated. The only instance where it returns to anything approaching normal seems to be when all or almost all of your recent trips are in HV mode. So I agree with the supposition that it may be calculating based on total mileage and doesn’t separate out the HV miles.

Another WAG would be that maybe they just ported over the same software calculation from the FC and BEV Claritys which only have one mode. In any case the engineer that let this car go into production with such a glaring (and easily remedied) software error was grossly overpaid.

The Honda app does not even report the odometer reading correctly. I have driven 1133 miles. App says 1073.


Sent from my iPhone using Inside EVs

 

[loomis2]

The Honda app does not even report the odometer reading correctly. I have driven 1133 miles. App says 1073.


Sent from my iPhone using Inside EVs

It does report it correctly, it just doesn't always update it. I'm sure the day the app read your odometer it was correct. My app went over a month without updating the odometer in the app. It also has a hard time updating the car's location in the app. It is very annoying to the point of being useless for those things.

 

[bobcubsfan]

Right. Probably not a good link to the "mothership."

 

[loomis2]

Also, I don't think car companies are known for making good apps. I can't think of one, anyway.

 

[bobcubsfan]

The Nissan Leaf app was pretty lame.

 

[S&E]

A very useful chat. For me, it shows that the range estimate "problem" is here to stay Below are thoughts of this dedicated Honda driver on the 1000 mi HV and fluctuating EV estimates.

The current hypothesis is as follows: the on-board computer takes the total miles driven (in HV + EV) and divides them by the gasoline used = to get MPG. You can look up your MPG directly under the second "info" icon, which looks like a large gas station. For the happy EV users, such "MPG" reaches very high numbers, however the displayed ratio is numerically limited to 199 miles per gallon. If we fill the tank under these conditions, the computer should arrive at 199 mpg x 7 gal = 1393 mi. This is further numerically limited by the maximal displayed HV range of 1000 mi, since there is another range display in the bottom right which can only accommodate three digits. The maximal "total range" is about to 1000 HV + 47 or so EV = 1047 or so miles.

Taking a long ICE trip will not immediately help to "resolve" this calculation. For that the total distance driven (since the "trip" estimate, see dstauss comment) has to bring the mpg numbers to reality first. If the above hypothesis is correct, the MPG estimate is useful for something rather different: if I take my total miles driven (~2800 mi) and divide them by this 199 mpg, I get the total number of gallons used since day 1, i.e about 14 gallons, and, voila, I have used not more than two tanks so far.

If the above is correct, it may take time for Honda to explain to the dealership technicians that the HV range measures the minimum of 1000 mi and available gasoline times the ratio of total miles driven over the total gas used The purely electric Clarity does not encounter this issue.

The related EV puzzle is less dramatic, but more confusing. For a fully charged battery, I have seen the EV range estimates anywhere from 37 to 59 mi, at times passing through the advertised 47 mi. The web wisdom is to associate this with the outside temperatures, personal driving style, etc. However, the EV range estimates exhibit trends: for example, they may go up for a couple of weeks and then down for another couple of weeks, then up again. (In the meantime, I modified my charging routine four times: by going to public J1772, to at-home level1, to public J1772, to at-home level2, only adding to the EV range confusion. Also, the place where I live has hills, and this doesn't help to understand what the on-board computer is doing.) The computer has to take into account the miles driven in the HV mode, when the electric motor is engaged, and when the ICE only charges the battery, and in the Sport mode when both motors are engaged. It is then supposed to pro-rate the miles based on used resources by each energy source. But alas, they use different resources. One of them uses kWh the other one uses gallons. It would be natural to assume that the total distance just driven = MPkWh*external kWh used + MPG*gallons used (regardless of the on-board charging). Then, we have only two unknowns (MPkWh and MPG). To get the two unknowns from this relation, we just add more historical data, and perform regression. As a result, if you use ICE, it will impact the MPkWh estimate. Suppose you use HV "gently". Then ICE mostly charges the battery, and we have two energy conversions: from gas to electricity to mechanical. This has to be different from the aggressive driving mode and from the mode where ICE is acting alone. And all this might only be the tip of the iceberg. Honda could have added a program for the on-board computer to further optimize the energy conversion on-the-go, for a given driving style.

 

[Johngalt6146]

Pardon me for being over simplistic: When the ICE is on (either charging the battery or also running the wheels) an MPG can be calculated. Most car computers do that. Why don't the just take that number and multiply by the fuel in the tank to get an ICE range, and display it. I know that there are inaccuracies in this, but it would be a lot better than what we have today. I do this mentally anyway. From experience I know that number to be 40 MPG. So my ICE range on a full tank is 280 miles.
P.S. - My EV meter yesterday read 65.2 miles at 85 Deg. on a full battery just charged.

 

[Rajiv Vaidyanathan]

A very useful chat. For me, it shows that the range estimate "problem" is here to stay Below are thoughts of this dedicated Honda driver on the 1000 mi HV and fluctuating EV estimates.

The related EV puzzle is less dramatic, but more confusing. For a fully charged battery, I have seen the EV range estimates anywhere from 37 to 59 mi, at times passing through the advertised 47 mi. The web wisdom is to associate this with the outside temperatures, personal driving style, etc. However, the EV range estimates exhibit trends:

This is absolutely fascinating. While there are too many variables (ambient temperature, driving style, etc.) to reach any concrete conclusions, I seem to notice that when I am regularly using Sport Mode (as I did for a few weeks, my EV range estimate hovered close to 60 mph. However, when I just switched back to my normal Econ Mode, my EV range estimate has moved closer to the 50 mile range. I wonder whether this is because of S&E's hypothesis on how this range is calculated.

 

[dstrauss]

Pardon me for being over simplistic: When the ICE is on (either charging the battery or also running the wheels) an MPG can be calculated. Most car computers do that. Why don't the just take that number and multiply by the fuel in the tank to get an ICE range, and display it. I know that there are inaccuracies in this, but it would be a lot better than what we have today. I do this mentally anyway. From experience I know that number to be 40 MPG. So my ICE range on a full tank is 280 miles.
P.S. - My EV meter yesterday read 65.2 miles at 85 Deg. on a full battery just charged.

This is actually the only solution we are likely to get if, and until, there is a true model upgrade for the Clarity series. Despite the fact the Clarity is the best and most refined vehicle I have owned, it is clearly a "work in progress" because it is a plethora of compromises foisted on the FCEV chassis of the hydrogen system. This gives us more trunk space but at the expense looking like a head down beetle:

Why omit cross and side-traffic alerts?

Why no lumbar supports?

Why any hump at all in the center rear seat position?

Why only a keyhole pass through instead of flat seats with full pass through?

Why not have a hatchback with the shape and design of the current system?

Why no volume or other controls on the infotainment system when you are doing it everywhere else in the lineup?

Why use in-wiper fluid delivery rather than sprayers?

Why limit HV Charge mode to 58% of capacity, when the system clearly trickle charges at higher constant speed driving?

Why no EV lock mode where it can't leave EV until battery level is too low?

This is in no way intended as a criticism of the car I love. I'm just trying to point out there are a lot of design and cost choices going on here, and many compromises by the fact it is staying in its own badge rather than being a part of the Accord line. These are still early times for long (50 mile +/-) EV range PHEV's, and you can see every manufacturer is struggling with design/function compromises (with so much temperature variation in EV estimates, why would anyone want a 25 mile or less EV mode PHEV).

 

[S&E]

This is for those who would like to see an example. Suppose, on day 1 you drove ~100 miles and used (external) 7 kWh and 1.5 gallons of gas. On day 2 you drove back and used 2 gallons of gas. What was your MPG? Day 2 gives 50 mpg, and with day 1, you find (100-1.5*50)/7 = 3.6 MPkWh. Simple? Except that on your next trip to the same place (on day 3) you forgot to press the HV button. You used 12 kWh and 1 gallon of gas. Now there are options. If you use day 3 and day 2 you get 4.2 MPKWh. If you use day 1 and day 3, you get 4.6 MPkWh and 46 MPG. With regression, you get 4.1 MPkWh and 49 MPG. Now the HV range estimate is anywhere from 318 to 350 mi, and the EV range is from 42 to 55 mi.

Why limit HV Charge mode to 58% of capacity, when the system clearly trickle charges at higher constant speed driving?

The limit is for ICE charging, not for deceleration charging. It is there because of the battery charging curve, and it will lower the gas efficiency if removed.

 

[Johngalt6146]

Good List - Thnaks. I hope that Honda reads it. Looking at my 280 mile simple ICE calculation, I'm reminded of my 1963 Tbird in the picture at the left. It had a 20 gal. tank and got 13 MPG, so it only went 260 miles on a tank - less than the Clarity! It actually went less, since at 35,000 miles or so, its mean time to the failure of some component seemed much less than its ICE range. Hah!

This is actually the only solution we are likely to get if, and until, there is a true model upgrade for the Clarity series. Despite the fact the Clarity is the best and most refined vehicle I have owned, it is clearly a "work in progress" because it is a plethora of compromises foisted on the FCEV chassis of the hydrogen system. This gives us more trunk space but at the expense looking like a head down beetle:

Why omit cross and side-traffic alerts?

Why no lumbar supports?

Why any hump at all in the center rear seat position?

Why only a keyhole pass through instead of flat seats with full pass through?

Why not have a hatchback with the shape and design of the current system?

Why no volume or other controls on the infotainment system when you are doing it everywhere else in the lineup?

Why use in-wiper fluid delivery rather than sprayers?

Why limit HV Charge mode to 58% of capacity, when the system clearly trickle charges at higher constant speed driving?

Why no EV lock mode where it can't leave EV until battery level is too low?

This is in no way intended as a criticism of the car I love. I'm just trying to point out there are a lot of design and cost choices going on here, and many compromises by the fact it is staying in its own badge rather than being a part of the Accord line. These are still early times for long (50 mile +/-) EV range PHEV's, and you can see every manufacturer is struggling with design/function compromises (with so much temperature variation in EV estimates, why would anyone want a 25 mile or less EV mode PHEV).

 

[bobcubsfan]

The Nissan Leaf has a hump in the rear as well. It serves no purpose. I actually heard a rumor that Honda is going to discontinue the Clarity. The fact that prices are plummeting might support that.

 

[leehinde]

Honda seems to like to modest social engineering with its range calculations. My previous car was a Civic Hybrid with a 13 gallon tank and it would show a zero range when I had 3 gallons left. So, I easily had 120 miles left. I'd have no bars left on the gas gauge and I don't think I ever put more than 11 gallons of gas in at one time. I took it to mean the nice engineers at Honda really didn't want me running out of gas.

 

[dstrauss]

The Nissan Leaf has a hump in the rear as well. It serves no purpose. I actually heard a rumor that Honda is going to discontinue the Clarity. The fact that prices are plummeting might support that.

Where'd you hear that Bob - what a downer?

 

[dstrauss]

Honda seems to like to modest social engineering with its range calculations. My previous car was a Civic Hybrid with a 13 gallon tank and it would show a zero range when I had 3 gallons left. So, I easily had 120 miles left. I'd have no bars left on the gas gauge and I don't think I ever put more than 11 gallons of gas in at one time. I took it to mean the nice engineers at Honda really didn't want me running out of gas.

As a former Prius owner, that is a good business practice, because if you run it out of gas on a hybrid you can get some serious potential damage issue to the traction battery, much like the bad old days (70's) of running a Volkswagen Rabbit diesel out of fuel.