[obermd]

Anyone have any experience with the Clarity on the interstates through Pennsylvania? Will I need to keep the battery charged driving across the PA "mountains" at 65-70 MPH or is the ICE sufficient?

 

[ClarityDave]

Anyone have any experience with the Clarity on the interstates through Pennsylvania? Will I need to keep the battery charged driving across the PA "mountains" at 65-70 MPH or is the ICE sufficient?

If I hear you right, you’re basically asking whether the ICE alone has enough power to propel the Clarity at a speed of 70 mph up the steepest incline in PA. I see that you live in Denver. Is it possible that you could test this out on a fairly steep mountain road near you? I would imagine that if the engine can handle that load in Denver then it will be a piece of cake in PA where you’ll be at a lower altitude with denser air.

 

[Trolle]

I think obermd is used to the 7000 feet mountains near Denver.

Highest peak in PA is somewhere around 2500 feet.

I took a trip from upstate NY this spring going through PA on I 81 down through the West Virginia mountains to AL running ICE all the way with fairly decent climbs 70 - 80 mph, no issues.

Eastern mountains are molehills next to Colorado. I was in Estes Park this early fall, now there are some real mountains nearby.

 

[obermd]

If I hear you right, you’re basically asking whether the ICE alone has enough power to propel the Clarity at a speed of 70 mph up the steepest incline in PA. I see that you live in Denver. Is it possible that you could test this out on a fairly steep mountain road near you? I would imagine that if the engine can handle that load in Denver then it will be a piece of cake in PA where you’ll be at a lower altitude with denser air.

I can attest that the Clarity's ICE is insufficient to power the car up our high mountains. This is why I asked the question.

 

[ClarityDave]

I can attest that the Clarity's ICE is insufficient to power the car up our high mountains. This is why I asked the question.

That is very interesting. Have you found that it will climb certain inclines albeit at a lower speed like 50-60 mph? There is a general rule in aviation that I’m sure applies to any normally aspirated internal combustion engine, at 8,000 feet above sea level an engine can only make 75% of the power it does at sea level.

 

[ClarityDave]

I think obermd is used to the 7000 feet mountains near Denver.

Highest peak in PA is somewhere around 2500 feet.

I took a trip from upstate NY this spring going through PA on I 81 down through the West Virginia mountains to AL running ICE all the way with fairly decent climbs 70 - 80 mph, no issues.

Eastern mountains are molehills next to Colorado. I was in Estes Park this early fall, now there are some real mountains nearby.

Yeah, I’ve driven across PA on the turnpike from around Pittsburg all the way to Philly in our Chrysler Pacifica PHEV. It is a heavier vehicle with a bigger 6-cyl engine and it had no problem keeping up at 70 mph.

 

[Trolle]

"at 8,000 feet above sea level an engine can only make 75% of the power it does at sea level"

Very good point, that has to factor in.

 

[obermd]

That is very interesting. Have you found that it will climb certain inclines albeit at a lower speed like 50-60 mph? There is a general rule in aviation that I’m sure applies to any normally aspirated internal combustion engine, at 8,000 feet above sea level an engine can only make 75% of the power it does at sea level.

It struggled up the north side of Grand Mesa at 40 MPH. Grand Mesa tops out at 10,000 ft. and it's a 4,000 ft climb. Regen on the way down the south side was nice - almost half the battery was recovered. Later on the same trip I made sure I kept the car in HV mode and it had no problems getting over Red Mountain (11,018 ft) and several other passes of 10,000 ft or higher.

 

[obermd]

Yeah, I’ve driven across PA on the turnpike from around Pittsburg all the way to Philly in our Chrysler Pacifica PHEV. It is a heavier vehicle with a bigger 6-cyl engine and it had no problem keeping up at 70 mph.

My 2017 Volt is will very happily drive anywhere in the US with no battery reserves.

 

[2002]

My 2017 Volt is will very happily drive anywhere in the US with no battery reserves.

I wonder if some of that is due to the lighter weight of the Volt, even though it's not all that much lighter. That may also be why the Volt will let you stay in EV even with the accelerator pressed to the floor.

What I think really hampers the Clarity in these situations is its unwillingness to use battery power below the set point for extended periods of time. You could have 90% SOC but if you have reached the set point in HV mode then it refuses to use the battery and will even try and charge the battery if it drops below the set point. You can do HV reset (momentarily turn HV off then back on again) which sets it a little lower, but that only helps briefly and anyways you shouldn't have to do that. The fact that people are doing HV reset means the software is not doing what people want. There should be a mode (maybe called HV Power) that you can select where it is willing to use some battery power to supplement the engine for extended periods like during a hill climb. If the SOC starts getting too low then you can always switch it back to regular HV Mode. In fact this version of HV mode could also make life quieter on city streets, for those willing to give up some EV range it would keep the engine off as you accelerate from a stop and then only start using the engine when the acceleration is finished (or tapering off), at that point not as much power is needed from the engine plus wind and road noise will pretty much drown it out anyway.

 

[obermd]

NOTE: Unless otherwise specified, Volt refers to the 2nd Generation Volt (2016-2019).

I wonder if some of that is due to the lighter weight of the Volt, even though it's not all that much lighter. That may also be why the Volt will let you stay in EV even with the accelerator pressed to the floor.

The Volt was designed to be a BEV first and then a hybrid second. This translates into a much "purer" (whatever the heck that means) EV experience. The Clarity is a hybrid first - Honda missed the boat on this one because their FCEV and BEV versions have an electric motor more than powerful enough to not require ICE assistance. The Volt's lighter weight, combined with the 50 KW ICE power generator allows the 2nd Gen (2016-2019) Volt to handle the worst climbs using ICE only. The ICE in the earlier Volts wasn't powerful enough to do this.

What I think really hampers the Clarity in these situations is its unwillingness to use battery power below the set point for extended periods of time. You could have 90% SOC but if you have reached the set point in HV mode then it refuses to use the battery and will even try and charge the battery if it drops below the set point. You can do HV reset (momentarily turn HV off then back on again) which sets it a little lower, but that only helps briefly and anyways you shouldn't have to do that. The fact that people are doing HV reset means the software is not doing what people want. There should be a mode (maybe called HV Power) that you can select where it is willing to use some battery power to supplement the engine for extended periods like during a hill climb. If the SOC starts getting too low then you can always switch it back to regular HV Mode. In fact this version of HV mode could also make life quieter on city streets, for those willing to give up some EV range it would keep the engine off as you accelerate from a stop and then only start using the engine when the acceleration is finished (or tapering off), at that point not as much power is needed from the engine plus wind and road noise will pretty much drown it out anyway.

Hybrid (HV) hold mode is just that - keep the traction battery at the level it was at when the driver selected HV, which means going full electric after descents and recharging after climbs or other surge power requirements. The purpose of this is readily apparent in Europe where some of the major cities have instituted a BEV only requirement for inner city personal vehicles. HV mode allows the driver to get on the highway, switch to gas, and then switch back to EV for those areas. The 2011-2012? Volt didn't have this mode (which GM calls Hold Mode). What Volt owners were doing was putting their car into Mountain Mode, which preserves the battery at a low level and will recharge the car to that level from the gas engine, and then put the car back into normal EV mode for the city. GM responded in 2013 (year?) by adding Hold Mode to address this.

My Volt actually keeps a 400 W buffer at the bottom and taps it to use it's electric motors to accelerate under heavy load, even when the battery is depleted. The ICE will then rev up to recharge the battery, leading to a rubber band effect on the engine sounds. The Clarity appears to keep a smaller buffer for this purpose. Normally an empty battery shows two bars on the battery display but I've seen the car showing one bar. It's when the car is showing one bar that the ICE really gets a workout.

Where Honda missed the boat is by not giving the driver the ability to put the car into HV Charge (Volt Mountain) mode as soon as they leave their driveway, allowing the car to drive electric for a ways and then ensuring the battery is maintained at a factory preset level.

 

[ClarityDave]

My Volt actually keeps a 400 W buffer at the bottom and taps it to use it's electric motors to accelerate under heavy load, even when the battery is depleted. The ICE will then rev up to recharge the battery, leading to a rubber band effect on the engine sounds. The Clarity appears to keep a smaller buffer for this purpose. Normally an empty battery shows two bars on the battery display but I've seen the car showing one bar. It's when the car is showing one bar that the ICE really gets a workout.

Again, watts are a measure of rate not amount. So perhaps you meant to say that the Volt keeps a 400 Wh buffer...
Here is a good explanation of the difference between watts and watt-hours: https://www.greenlifestylechanges.com/making-sense-of-watts-and-watt-hours/

If you want to state how much power a battery can deliver at any one instant in time, then you can express that in watts. If you want to state how much energy a battery holds in total or in a buffer, then you would express that in watt-hours. You can charge a battery at a rate of a certain number of watts but to express how much energy you’ve put into a battery, how much you’ve drawn out, or how much is being held as a reserve or buffer, that is expressed in watt-hours.

Here’s another example to illustrate with volts. An A23 battery is a 12-volt battery. It’s smaller than your pinky finger. An automotive 27F battery is also a 12-volt battery but it is much larger and weighs on the order of 50 pounds. Even though both batteries are 12-volt batteries, the 27F has enough energy to crank an 8-cylinder engine for many minutes whereas an A23 battery would not even have enough energy to budge the crankshaft.

P.S. I’m not saying this to slam you or merely for the purpose of telling you that you’re wrong. I’m just trying to help you understand what a watt is and what a watt-hour is.

 

[obermd]

typo - sorry. 400 Wh buffer is what I thought I typed. Unfortunately I can't seem to edit the post anymore.

 

[semenzato]

Check out how I drive from 0 to 7000 ft here: https://www.clarityforum.com/forum/549-honda-clarity-plug-hybrid/1333-driving-mountains.html

 

[Greg L]

Clarity in PA

I drive my 2018 Clarity Touring on the highway in HV Sport mode with the regenerate paddles at full regeneration. In Sport HV Mode, the car has much more power and in Sport, tapping the left paddle 4 times puts it into the highest regeneration mode so any coasting or braking will regenerate quickly. Also, when the car needs to use EV along with HV in Sport for additional power, the ICE will rev higher at times to restore energy to the battery to keep it at a high level where it began. The car is quite nice to drive on the highway in this mode. To make it even better, engage the Lane Keep Assist System (LKAS) and the car will keep you safely in your lane!
The more I drive this car, the more I like it!

 

[claritypicker]

Switch to battery during steep incline

We have driven regularly through PA, while heading further north. We stay on HV most of the way, while keeping battery at atleast 50% level. If the incline is too steep, we switch to battery. Clarity makes an annoying buzzing bee sound and struggles to climb during steep inclines.