Top Wishes (to Honda) - Persistent Modes (or persistent HV), and Quieter Gas Only

Allow me to share the perspective of us flatlanders on this issue.

I had a friend who, when the phone companies were decommissioning the microwave links, bought some of their towers. He started a business renting antenna space for companies that needed radio communications. Our conversation went something like this:

Him: "I've got towers on all the mountains around here."
Me: "Mountains?"
Him: "Yeah, like this one is 300 feet above the average terrain elevation."

300 feet constitutes a mountain around here.

But I am very interested in these quirks of driving a PHEV. It's a whole new world to explore. Thanks to all of you for sharing.

 

Now that winter is reducing my EV mileage I started looking through these (very helpful) threads on the best way to drive the car. I try to stay in EV mode in the city and on the congested highway part of my commute. When traffic clears on the highway the HV goes on because at 23¢ per kWh gas is cheaper then electric. I think that because the car is so quiet in EV mode when the engine goes on I notice the noise more then I would in any gas car. I do wish there was some way to slow the engine because it just seems that it is working much harder then it needs to in maintaining highway speed - or it’s all in my head because the EV is so quiet and the HV might just be as loud as any gas car and I’m not used to it anymore. A tachometer might be interesting in the Clarity to show what that engine is really doing.

 

My thoughts exactly. I find the sound of the engine very annoying in stop-and-go driving, but I am not sure whether that's because it is loud or that I am spoiled by how smooth and quiet things are on EV.

 

Its quieter in gear mode on the highway. I am finding I can get it to stay in gear mode 90% of the time if I drive without using the cruise control. When I use the cruise it varies speed too much and is in gear mode only about 10% of the time.

 

This article has been referred to in previous threads, but I can't find them right now. So this is the free preview of the SAE article. The most interesting are Figure 5 and Figure 7 and 10. Figure 5 shows the EV range at a given mph.

https://www.sae.org/publications/technical-papers/content/2018-01-0415/preview/

 

Great info, thanks. Key points for me are maximum EV efficiency is at about 28 mph, and the engine is turning about 2500 rpm at 70 mph in gear mode. Confirms the best way to drive the car is EV off the highway, HV on the highway, unless you are lucky enough to have super cheap or free (work) electric rates.

 

That’s a great article and very much supports using HV at highway speeds. Also explains why the engine sounds so loud when exiting the highway. It’s the perfect storm of speeds dropping down from >60 through 50 & 40 - which looks like the speeds where the engine runs the fastest. I’m one of the lucky ones that gets free charging at work with a round trip commute of 35 miles so I almost never use the engine. Three months and 3300 miles using 9 gallons of gas.

 

This is great! The 2013 Accord Hybrid-specific paper "Efficiency Enhancement of a New Two-Motor Hybrid System" by Naritomo Higuchi and Hiroo Shimada was a good discussion of Honda's i-MMD system, but this one actually discusses the Clarity PHEV. Can't wait to see the full paper. Thank you very much.

 

Definitely an option, set with all the other options. I rather think that Honda designers felt that there were already too many options and were afraid that the driver population would be overwhelmed. I don't think they realize that we can simply take the default for the options we don't care about, and people who care about none of them can take all the defaults.

Personally, I would like to see an option to shift to HV after some period of highway driving, and back to EV when no longer at speed. I dislike remaining in HV mode as I drive through small towns, so I generally drop out of HV until I get established back on the highway. I'd like it if the car did that for me.

 

Dan, the only way to know the health of your battery is to have the dealer measure the Battery Capacity Signal with their HDS. It was supposed to be done at the PDI. It should read close to 55 Ah when new. Warranty replacement is at 36.6 Ah.
Since I bought mine in Feb and the new PDI came out in March, it was not done for me. My dealer ran it for me when they did the first update.
Ken

 

When someone obtains the full SAE paper, please post it here as a new thread under "Clarity SAE Paper" or such so that we can't miss it in the sea of threads. Thank you.

 

I think mine has.

Having mountains around, I tend to start on EV and go to HV at some predetermined point, such as 10 EV miles remaining, then hit HV. The EV miles remaining then hovers around 10 miles, but mostly on the low side. But pretty sure on downhills I’ve seen it go to back to 10+ for a while.

I’ll check for it tomorrow, when I have a longer mountain drive planned.

 

Mine went from 17 to 16 then back to 17 the other day, in HV mode. It was obviously hovering on the boundary, dropped, then it did not take much increase in charge to make it hop back. So, yes, I have seen it increase while in HV not-charge mode. I'm a flatlander, so no long hills to drive down while harvesting regen.

One of the questions I have is the scale on the power meter for the area marked "Charge". I sincerely hope that it's not the same as the big area that measures power used, since there's only a tiny area that measures charge when compared to the area that measures use. Given that we don't know the scale, it's not possible to understand how much energy we're actually capturing by using regenerative braking. My suspicion is that it's mostly a feel-good feature and makes no significant difference in EV range unless you're descending a long downhill.

 

The battery test was supposed to be done at the PDI per Sevice Bulletin 17-093. I have attached a copy. I showed it to my dealer and they ran the test for me since it had not been done.
Hope this helps.

 

People read the owner’s manual?


Sent from my iPhone using Tapatalk

 

The cars computer does not let the battery reach”empty”. That’s why you always see 2 bars remaining on the gauge. At that level, there is enough charge to support continued HV driving. Unless something happened to your car, your battery should be fine. EV range estimation varies greatly between users depending on climate and driving habits, apparently. I’d guess your dealer can test the battery for faults if it’s a concern.


Sent from my iPhone using Tapatalk

 

Your cars battery was damaged during shipping/delivery? Won’t Honda warranty that?


Sent from my iPhone using Tapatalk