Mountain Driving: HV or EV

insightman said:
I can't understand why you would feel sluggish response from HV unless you're really talking about HV CHARGE, which saps some of the ICE's power to charge the non-contributing battery.
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It is my understanding in HV mode there are conditions where it will also sap some power to send to the battery if the SOC falls too far below the HV mode set point.

I don’t have any real issues even with 0 EV range. The engine starts and runs as needed and higher revs do not scare me. I used to ride mini bike motorcycles so small engines working hard is not big deal to me. The car is smart enough to stay within limits. Granted my car is still low miles and hill climbs haven’t been super duper steep. My approach to zippy small Pocono mountain climbs (the Pocono Mountains are not really “mountains”) has been to let the car use whatever battery is left and encourage the engine to start through heavy accelerator application which is helped psychologically with Sport mode’s remapping of the pedal. Since this is outside my electric range anyway when I make those trips engine use is unavoidable so I might as well have it run when it is most useful. Almost forgot...cabin heat off during climb. AC doesn’t seem to have much impact.
 
DaleL said:
Although the engine on the Clarity can directly couple with the drive train between about 45 to 65 miles an hour, normally propulsion comes from the 181 hp traction motor. The battery can provide up to 121 hp and the engine generator provides up to 60 hp. In HV mode, the car attempts to maintain the battery charge, but will borrow as needed for acceleration and upgrades.

There seems to be a lot of variation in Claritys and how they behave (noise, sluggishness, etc.). On smooth pavement, my Clarity Touring is very quiet in HV mode at 75 mph. There is absolutely no wind noise and I cannot hear the engine. Course pavement results in the expected road noise. I find low speed driving in HV mode (battery depleted) to be far less refined. The engine revs are quite audible. As a result, I always switch to HV mode when driving at highway speeds to save the battery charge for low speed driving.

The longest drive that I have made was a trip from Florida to Ohio and back in 2018. The total trip distance was 2032.2 miles. I fueled a total of 8 times and used 45.8 gallons. Overall mileage was 44.4 mpg. If I subtract out the approximately 50 miles that were driven in EV mode, the gasoline mileage was still a very respectable 43.3 mpg, as calculated by actual miles driven and fuel used. The trip computer overestimated the fuel economy by nearly 10%. The drive included the WV turnpike through the Appalachian Mountains. During the drive I kept the battery charge at about 50%. I never felt any sluggishness.
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Douglas Firs said:
I've seen this topic come up in other threads, but I'm not sure the jury is out on this yet. Have you had a better experience driving through mountains in HV or EV?

I'm not interested in what's most efficient, but rather which you have found more powerful. My experience zipping through the hills outside of SF (with +1200ft elevation gain over 4 miles as the biggest climb; 45mph) is MUCH more enjoyable in EV. Car is very sluggish in HV. We're going to Tahoe in a few weeks and if we have electrons to spare when we hit the mountains, I'll be going into EV for some of it. Not sure how it will compare with driving through the gentler hills in the Bay Area.

Are there factors like speed, grade, distance, curves, etc that matter for either?
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Douglas Firs said:
I've seen this topic come up in other threads, but I'm not sure the jury is out on this yet. Have you had a better experience driving through mountains in HV or EV?

I'm not interested in what's most efficient, but rather which you have found more powerful. My experience zipping through the hills outside of SF (with +1200ft elevation gain over 4 miles as the biggest climb; 45mph) is MUCH more enjoyable in EV. Car is very sluggish in HV. We're going to Tahoe in a few weeks and if we have electrons to spare when we hit the mountains, I'll be going into EV for some of it. Not sure how it will compare with driving through the gentler hills in the Bay Area.

Are there factors like speed, grade, distance, curves, etc that matter for either?
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I live in Colorado and travel the mountains a lot. I put into sport HV from the time I leave home to the time I get into the city. No power problems and it runs 70 to 75 the entire route. I have tried it in EV and it just lasts a few miles and then switches over to HV without as much power because it can not use the EV with the gas at that point. ANY time I know my trip will be more than my EV range I use HV from the beginning.
 
insightman said:
The traction motor can produce 121 horsepower when operating on battery power alone. When the ICE is turning the starter motor/generator to supplement the battery power, the traction motor can produce 181 horsepower.
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Does anyone know how many horsepower the traction motor can produce if the battery isn't contributing at all? Normally it gets 121HP from the battery and the motor/generator can boost that to its full potential of 181HP ... but can the motor/generator provide more than 60HP if the battery isn't pulling its weight?
 
I did not know, I did not mean go find the answer, I was trying to remember where I saw some good info that might be interesting. But, here is a better thread: "driving on a depleted battery" https://insideevsforum.com/communit...riving-on-a-depleted-battery.3647/#post-35567

Mostly, it is best guesses, Honda does not publish much beyond those power curves in many of the posts. You can see there is a lot of well informed speculation, but no one (as of yet) seems to definitively "know" these answers. Anyway, sorry if I came across as snitty :)
 
MichiganClarity said:
Does anyone know how many horsepower the traction motor can produce if the battery isn't contributing at all? Normally it gets 121HP from the battery and the motor/generator can boost that to its full potential of 181HP ... but can the motor/generator provide more than 60HP if the battery isn't pulling its weight?
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Honda rates the ICE at 103 hp, but they have not revealed how much power the starter motor/generator can generate.

I started what turned into a looong thread in a quest to learn how the Clarity can achieve Honda's specified 212 hp. I didn't read any definitive answers to my question in that thread. If you simply add the 181-hp motor and the 103-hp ICE, you get 284 hp. Because Honda claims only 212 hp, not 284 hp, their method must take into account the fact that the power peaks don't match up to be simply additive. I doubt the discrepancy is due to losses in the system.

Some people speculated that the 181-hp can soar to 212-hp for a few seconds when maximum acceleration is demanded. This would argue for a starter motor/generator that CAN generate more than 60 hp. Honda remains mum.

The Clarity has 3 basic underlying drive modes: EV drive (battery only driving the traction motor), Hybrid drive (battery power + ICE-generated power driving the traction motor), and Engine drive (when the clutch engages to enable the ICE to drive the wheels through a 1-speed gearbox). As we can see on the dashboard, the battery can still contribute power in Engine drive mode. If the Clarity can achieve 121 hp in EV drive mode and 181 hp in Hybrid drive mode, is Honda's specified 212 hp achieved in Engine drive mode? If the 103-hp ICE can generate a maximum of 60 hp of electricity, can Engine drive mode send some of the 43 leftover horsepower through the clutch to the wheels? Does Engine drive mode send 31 hp to the wheels to make the total 212 hp?

Then there's real-world experience butting in. If you're driving your Clarity PHEV in Engine drive mode ("gear mode" some call it based on the gear icon that indicates Engine drive mode is in effect), the car feels anything but powerful because unless you're using the cruise control, you're carefully feathering the accelerator to stay within the narrow window of Engine-drive compliance.
If you then floor the accelerator, you don't shoot forward with the power of 212 horses. Instead, the Clarity drops Engine drive mode like a hot potato and accelerates in Hybrid drive mode, which supposedly provides a maximum if 181 horsepower.

Then there are people who say they don't feel a lack of power going up mountains with a depleted battery. That experience would argue for a starter motor/generator that can produce more than 60 hp worth of electricity to drive the traction motor. The mystery continues.
 
sniwallof said:
I did not know, I did not mean go find the answer, I was trying to remember where I saw some good info that might be interesting. But, here is a better thread: "driving on a depleted battery" https://insideevsforum.com/communit...riving-on-a-depleted-battery.3647/#post-35567

Mostly, it is best guesses, Honda does not publish much beyond those power curves in many of the posts. You can see there is a lot of well informed speculation, but no one (as of yet) seems to definitively "know" these answers. Anyway, sorry if I came across as snitty :)
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I did take it as snitty, but as is often the case, that was a reflection of my mood instead of your intention. Thank you for taking the time to reach back out and for the additional information. I apologize that I wasn’t more generous in my read of your initial response.
 
insightman said:
Honda rates the ICE at 103 hp, but they have not revealed how much power the starter motor/generator can generate.
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I guess that’s the million dollar question. I haven’t run into a situation yet where I don’t have the power I think I need, but the experience of others makes me nervous. Thanks for the information.
 
Could it be that there is more instant torque using EV (battery only power supply) vs. HV (battery + generator)? It sounds like from those other threads torque is more important for acceleration, at least at lower speeds. If EV does have more available torque in the 35-40mph range I've been driving on hills, that's why it's zippier. And/or maybe HV is capable of providing a similar amount of torque under those conditions, but only if you really gun it. So it *feels* like EV is zippier because you don't have to accelerate as hard. That would fit with the experience of Sport vs. non-sport modes, i.e. the trigger points for getting oomph are just altered. Food for thought.
 
Douglas Firs said:
Could it be that there is more instant torque using EV (battery only power supply) vs. HV (battery + generator)?
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When you consider that the same traction motor is driving the wheels in either situation, I don't see how the increased power added by the ICE-powered starter motor/generator could result in decreased performance.
 
insightman said:
When you consider that the same traction motor is driving the wheels in either situation, I don't see how the increased power added by the ICE-powered starter motor/generator could result in decreased performance.
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It's not the fact that the traction motor is driving in both scenarios. It's the fact that the energy sources are potentially different based on EV vs. HV. Ie. battery-only vs. battery + generator (which is fuel by ICE.), which could produce different horsepower/torque under the same circumstances. We don't know the algorithm (unless someone has a diagram I am missing...)
 
Kind of related, yesterday our mostly slumbering bees awoke with a vengeance.

The conditions were a bit extreme. We were climbing from Tellico Plains, TN (980’ msl) to the high point on the Cherohala Skyway in NC (about 5,330’ msl) in roughly 30 miles. I had gone to HV mode with 14 EV miles remaining. Anyway, the engine did race at times, a bit more than we’ve ever heard before. Not horrible, and turning up the radio a bit kinda put it in the background.

As an aside, the EV range dropped as low as 6 miles during the climb. In spite of turning the car off and back on a handful of times, back in Tellico Plains we had fully recovered the EV miles plus 1, showing 15 EV miles remaining.
 
Douglas Firs said:
It's not the fact that the traction motor is driving in both scenarios. It's the fact that the energy sources are potentially different based on EV vs. HV. Ie. battery-only vs. battery + generator (which is fuel by ICE.), which could produce different horsepower/torque under the same circumstances. We don't know the algorithm (unless someone has a diagram I am missing...)
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So do you think it's possible the battery provides less power when the ICE is also providing power?
 
I think the issue is that we don’t know how much total energy the algorithm is telling the car to draw when in HV mode and how that compares to what the algorithm tells the car to draw when in EV mode, at the same trigger point. There’s also a possibility that there is a slight lag in power, initially, with ICE during acceleration compared with EV. Like very very small lag (10ths of a second) that could still be perceptible as “sluggish” compared with EV under some circumstances. And/or my other theory which is that it’s all in my head.


Sent from my iPhone using Inside EVs
 
Fast Eddie B said:
Kind of related, yesterday our mostly slumbering bees awoke with a vengeance.

The conditions were a bit extreme. We were climbing from Tellico Plains, TN (980’ msl) to the high point on the Cherohala Skyway in NC (about 5,330’ msl) in roughly 30 miles. I had gone to HV mode with 14 EV miles remaining. Anyway, the engine did race at times, a bit more than we’ve ever heard before. Not horrible, and turning up the radio a bit kinda put it in the background.

As an aside, the EV range dropped as low as 6 miles during the climb. In spite of turning the car off and back on a handful of times, back in Tellico Plains we had fully recovered the EV miles plus 1, showing 15 EV miles remaining.
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"Turning the car off and back on a handful of times" - Does that mean you toggled the HV?

Did you use HV Charge mode to recover the EV plus 1?
 
insightman said:
So do you think it's possible the battery provides less power when the ICE is also providing power?
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insightman said:
When you consider that the same traction motor is driving the wheels in either situation, I don't see how the increased power added by the ICE-powered starter motor/generator could result in decreased performance.
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Or does it just FEEL like there's more torque because the EV alone is so quiet and seamless?
 
David Towle said:
Or does it just FEEL like there's more torque because the EV alone is so quiet and seamless?
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I just cannot imagine any reason Honda's engineers would not unleash all the power available when the accelerator is floored. That's what cars are supposed to do. "Your honor, my client could have gotten around that lowered gate and cleared the crossing before the train hit him if only his Clarity hadn't become sluggish as it was trying to manage the HV 'set-point' to maximize fuel efficiency."
 
insightman said:
Honda rates the ICE at 103 hp, but they have not revealed how much power the starter motor/generator can generate.

I started what turned into a looong thread in a quest to learn how the Clarity can achieve Honda's specified 212 hp. I didn't read any definitive answers to my question in that thread. If you simply add the 181-hp motor and the 103-hp ICE, you get 284 hp. Because Honda claims only 212 hp, not 284 hp, their method must take into account the fact that the power peaks don't match up to be simply additive. I doubt the discrepancy is due to losses in the system.

Some people speculated that the 181-hp can soar to 212-hp for a few seconds when maximum acceleration is demanded. This would argue for a starter motor/generator that CAN generate more than 60 hp. Honda remains mum.

The Clarity has 3 basic underlying drive modes: EV drive (battery only driving the traction motor), Hybrid drive (battery power + ICE-generated power driving the traction motor), and Engine drive (when the clutch engages to enable the ICE to drive the wheels through a 1-speed gearbox). As we can see on the dashboard, the battery can still contribute power in Engine drive mode. If the Clarity can achieve 121 hp in EV drive mode and 181 hp in Hybrid drive mode, is Honda's specified 212 hp achieved in Engine drive mode? If the 103-hp ICE can generate a maximum of 60 hp of electricity, can Engine drive mode send some of the 43 leftover horsepower through the clutch to the wheels? Does Engine drive mode send 31 hp to the wheels to make the total 212 hp?

Then there's real-world experience butting in. If you're driving your Clarity PHEV in Engine drive mode ("gear mode" some call it based on the gear icon that indicates Engine drive mode is in effect), the car feels anything but powerful because unless you're using the cruise control, you're carefully feathering the accelerator to stay within the narrow window of Engine-drive compliance.
If you then floor the accelerator, you don't shoot forward with the power of 212 horses. Instead, the Clarity drops Engine drive mode like a hot potato and accelerates in Hybrid drive mode, which supposedly provides a maximum if 181 horsepower.

Then there are people who say they don't feel a lack of power going up mountains with a depleted battery. That experience would argue for a starter motor/generator that can produce more than 60 hp worth of electricity to drive the traction motor. The mystery continues.
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The car is mysterious. I have noticed the gear engage after flooring it. I’m pretty sure that’s how you get to 212. It probably only happens during a certain speed range.
I have also noticed power loss but only with a Depleted battery and low temperatures at the end of an aggressive climb up a 4 mile hill at about 6% grade. There were no beeps or anything but I noticed the power meter going down when my foot wasn’t moving.
 
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