I bought a 2018 Clarity in December with 6,000 miles on it. This weekend I had an opportunity to compare using the Hybrid mode on the highway, and EV mode in stop and go compared to using CHARGE Hybrid mode, and using EV mode in stop and go. I left home fully charged, with a full tank of gas, and let the EV run down until it automatically switched to Hybrid. I switched it into CHARGE mode and made it back to about 1/2 charged when I hit the dreaded Northern Virginia traffic on I-95 North around Fredericksburg. I switched back to EV (stop and go) and noticed the constant braking and creeping along kept the car charged to about the same level. Traffic would pick up a bit, but I left it in EV as long as I wasn't going above around 45. I got to Washington DC and parked it with maybe 15 miles of EV range remaining. Very little gas had been used. Day two I continued the same, EV in stop and go, CHARGE mode at highway speeds. Again, the traffic north of DC almost all the way to my destination was dreadful. It took three hours to get from D.C. to a town called North East, MD. That trip should have taken 90 minutes. After my event in Maryland, I headed south on Rt 40 to avoid another traffic snarl on I-95 south, and followed the same rule. I decided to go ahead and top off the gas tank, and I figured the miles per gallon. I completed my trip home using just the Hybrid mode, EV in traffic. I topped off the tank when I got home to see what the MPG in Hybrid mode had been. So here's the results. First method: I drove 237.7 miles, and put 4.382 gallons of gas in the car when I topped it off, so I got 54.2 MPG. Second method: I drove 195.4 miles and put in 3.780 gallons, getting 51.7 MPG On a side note, the last time I had put gas in the car was in January; I had driven over 2,000 miles on that tank and only had used 2 gallons when I filled it up for this trip.
Well, I think your scenario(s) were far too complicated to attempt drawing any meaningful conclusion. One thing I was pondering while reading your description was the "EV Range Remaining". You said it was 15 miles at the end of 'method 1'. What was it at the end of 'method 2'? You can easily be deceived by not accounting for how much energy is stored in the battery when comparing two scenarios. More fundamentally though, if you want to compare 2 'methods', everything needs to be as identical as possible (aside from the variable you want to test). Otherwise you can't know if any measured differences are due to the thing you are changing or other variables beyond your control. In this case, I think your result was dominated by variables that were beyond your control.
I periodically run EV miles down to zero, just curious about how far I can really go compared with the guess-o-meter’s prediction. I then HV CHARGE back to a cushion of 5-10 EV miles for the rest of the trip. But I think physics tells us that efficiency has to take a hit doing it that way, due to losses in the discharge/recharge cycle. It’s apparently only a small hit, but it has to be there. Better is to just switch to HV mode with your preferred reserve. Or, as I’ve said before, “Don’t fear the zero” and just let the car do its own thing. Works fine except in the mountains, where holding a reserve can help avoid the angry bees on steep grades.
EV range will be maximized in heavy stop and go traffic, urban driving, speeds below ~45mph, etc. I’ve exceeded 65 miles under such conditions. EV range will diminish rapidly at sustained high speeds, particularly if going uphill. I’ve depleted it in as little as 25 miles. There’s nothing wrong with using EV at high speed for drives of 40 miles or so. If the trip is longer, switch to HV and use EV where appropriate. HV Charge is a convenient feature. There are some pesky thermodynamic laws that indicate it is less efficient than using electrons. Some owners have opted to use it where gas is/was cheap and electricity is expensive. Either method will likely have a minimal impact on one’s retirement plans. The manual recommends using HV Charge at sustained high speeds. It is a common practice to take note of miles traveled between fuel stops. My best is ~3500 miles on ~6 gallons. I believe one or two owners have gone as far as 11,000 miles.
This isn't an academic journal and you aren't the peer review board. I welcome anyone who wants to participate here but I especially welcome anyone who takes the time to report their experience and numbers to explain it. TotalClarity, thanks for taking the time to participate.
I had a similar trip a few weeks back driving from central NJ to DC. I started with EV on local roads and switched to HV on highway. There are a few service area in Maryland (I think) that had free level2 chargers. I didn't charge though because I found out afterwards. Switch back to EV in DC until it ran out of charge and stayed in HV. It think I used like half a tank of gas. BTW, gas in Baltimore is cheap!
I think your comparison tests are very conclusive. The main difference being that you used hv charge to build up range on one trip and also had 15 miles of tange left at the end of that trip. You clearly stated that you started in ev mode and drove until depleted on both trips. Since you never used hv charge on the second trip we can safely assume you had little to no ev range remaining. It's really not rocket science that when in hv charge you can gain better overall efficiency on road trips. I recently did a hv charge test and at about 70 mph for 31 minutes and about 34 miles traveled i went from about almost zero ev range until max charge completed. While doing so i was getting 28mpg and gained 26 miles of ev range. So the 1.1 gallons of gas used in 34 miles traveled plus the 26 miles of ev range gained =54 to 55 mpg. Compared to about 40 mpg in hv mode. I do realize that hv charge efficiency varies depending on battery and ambient temps. The above test was done at 60 degrees f.
I was not my intention to discourage participation in any way... I always try to think about whether the data presented supports any conclusions drawn. Sorry, I can't help myself !
I concur. Complicated, incomplete data and random. It’s 2 completely different trips. Various amount of time, distance and speed, in different driving modes. Was the car fully charged after Day 1? i appreciate others sharing their experiences with the car. This just seems to be 2 separate trips that yielded an almost insignificant difference of 2.5mpg in fuel economy.
