Charge Loss in HV Mode

I find the battery level will be maintained unless the engine can't supply enough power so the battery will be called in to help. For example accelerating or climbing hills. Steady driving on flat roads is best.

We can drive 200 miles without the battery level dropping on flat straight HW5 in California.

 

Agree with the statement above. EV range can also be impacted by HVAC usage.

I took a 2000 mile road trip last year driving an average of 3 to 400 miles a day and I would generally run it down to about 70% battery and it would remain roughly at that level or maybe down to 50% driving 70 to 75 on on the highway until I got closer to my destination and switched to EV. Steep inclines certainly make a noticeable dip

 

I have taken a few trips with my 2018 Clarity without charging the battery. I found the battery would lose charge until about 2/3 remained then it would maintain that level of charge unless I was driving 80 (a lot of speed limits in Utah are 80 mph) or climbing a hill. On one 800 mile trip which was all highway and 80% or more was at 80 mph, I left home with a full charge and returned home with 3 bars.

 

Being in LA, where we lived for 30 years, the traffic would possibly be an issue.

If you're in stop and go traffic you are accelerating often which will draw down on the battery. If you watch the EV indicator on the dash, even in HV mode, you'll see the car is often in pure EV mode. The gas engine can't really help until you are over about 60 mph.

At highway speeds the same rule applies. Steady driving at a constant speed is the solution. Watch for the gear icon which means the gas engine is providing all of the power to the wheels. If the gear icon is off you can be using both the gas engine and the electric motor. Best performance here is steady driving between 65 and 75 mph.

In our own case we regularly drive 25 miles round trip using Econ/EV mode for the whole trip. We charge at home. Our trips are to take our son to school and pick him up. 25 miles to drop him off, charge mid-day at home (we're retired), then 25 miles to pick him up. If your trip is 30 miles each way and you can charge at work you too could do the whole 60 miles in electric only and save the gas like we do.

A PHEV isn't the best choice for everybody. A Model 3 could be a better option for those with longer daily trips. It seems to me in your case a PHEV is still a good choice.

 

I have never experienced a scenario where HV did not hold the charge level.
Stop and go is not an issue because for every acceleration there is a corresponding regeneration.
The only case I can imagine where HV would not hold the charge would be a very long steep drive (up a mountain pass) for instance. We don't have that kind of mountain here.

 

Why aren’t you utilizing most or all of your EV range on the 60 mile commute? I’ve been doing a variety commutes in LA, mostly from low 40’s to mid 50’s. When HV is necessary, usually due to higher speeds for the entire trip, I’ll engage HV for 8-10 miles on the second leg and then finish on EV. It’s a bit less expensive to run on electricity than gas.

To address the rate of EV range (SOC) loss that you are experiencing, it doesn’t seem right. When you engage HV it will take a few minutes for the engine to warm up. During that time EV range will decline. Give it 5-10 miles and EV range should return to the set point. It will fluctuate, even on flat roads, perhaps by 3-4 miles. Up a significant climb it will drop much more. Again, give it time and it will return to the set point.

I’ve driven 700 miles from S Cal to S Oregon in 10 hours. Left it in HV, of course resetting it to HV after each fuel stop, and arrived having lost only 2-3 bars. On a trip like that, there is a chance of losing some EV range if a fuel stop is made before the EV range has returned to the set point. To elaborate, if you engage HV with 40 miles of range and pull in to a rest stop and turn the car off with 37 miles of range, it will restart with 37 miles of range. Now stop for gas with 35 miles of range showing, same thing happens. The another rest stop at 32, etc. etc.

You say that you spend “most” of the time in HV on 2, 60 mile commutes and the battery goes down to 2 bars after traveling those 120 miles. How many miles is “most”? It could take only 40 miles in EV to deplete the battery.

 

Correct. Given sufficient time, the SOC will return to the set point even after a long climb. And it doesn’t matter if the vehicle is in Engine Drive Mode, which is still a mode within the scope of HV Mode, or HV Mode. HV Mode should maintain SOC in a properly functioning vehicle. Understanding, of course, the situations where SOC will temporarily decline and how to allow SOC to return to the set point.

 

It is very simple... If your trip is longer than your EV range, drive in HV all the way. It will keep you close to the EV all day long. The only problem I had was I stopped for a rest break and FORGOT to put it back in HV when I started the car again. Ran the total EV out in 30 miles of steep passes. IF your car will NOT keep the EV at close to the starting EV range while in HV - there is something wrong with your car. I drove 80-85 for almost 1,000 miles and still had 3/4 of EV left.

 

I would try going to HV Charge mode, and see if it will bring the charge back up to 55%.

On another note, I find that it maintains that charge after the engine has gotten to operating temperature... Slight difference, but another issue.

Also, going in and out of HV mode will 'reset' the charge set point to the new level.

 

I know you said you have had the car for 'about a month'. Is it new, or did you purchase it used? What year is it?
There seems to be nothing unusual about your ~120 mile daily trip. It sure seems like something is wrong at this point,

I would offer one final thing you could try if you are willing. We have found that there is an occasional problem that can be 'cleared' with a hard reset. By hard reset, I mean disconnecting the negative terminal of the 12V battery for a few minutes, then reconnecting. This will cause the vehicle to report a number of ominous sounding errors, but these errors will clear after driving for a few minutes.

Keep in mind that when you do this, your driving history resets and the EV range estimates (Guess-O-Meter) will take a few trips before converging on reality again. There is a chance that this could correct whatever it is that is affecting HV mode. After doing this, you should verify your tire pressures and run a TPMS calibration. The manual describes how to calibrate the TPMS.

 

It does sound like your Clarity has an issue.

That said, on a long trip exclusively in HV, I’ve found the EV range will gradually increment downwards. This, from a trip N GA to S FL a while back:



On that trip the loss on most legs - almost all highway - averaged out to just a few miles. Regardless, my true mpg of 42.6 mpg is still pretty impressive for a car this size, even considering the “half tank” of electricity consumed enroute.

Also of note: the car’s calculation of mpg was consistently optimistic by about 12%. Consistent enough that I still think it’s intentional.

 

That is how the vehicle been operated, 110-115 miles out of 120 are reportedly driven in HV. Yet the battery is being depleted to 2 bars over 2 days and 2, 60 mile round trips.

The car is being driven in S Cal, where it is likely that operating on electricity is less costly that operating on gas. I’d suggest the 60 mile commute be made in such a way as to use as much EV range as possible.

A question to the OP. Have you tried driving in EV Mode, using a relatively light throttle foot to avoid triggering the ICE? If so, what sort of range are you getting in EV?

A couple of possibilities could be:
1) HV Mode is not actually engaging
2) The traction battery has become defective and will not hold a charge or for some reason is rapidly discharging.
3) The generator is not charging the battery while in HV Mode.
4) ?

I’d get the car to a dealer.

 

That’s a neat chart. I may borrow all or part of it. If repeatable, it would indicate that the SOC is allowed to decline to 80-85% on the first leg. Perhaps in the first 20-30 miles. That would allow the battery to accept full regen.

The rest, mostly falls into what would be expected, losing a couple of miles with each off/on cycle. The 2, 5 mile drops are toward the high end but not completely unexpected.

 

That is not my experience. When I've driven in HV mode the car can do a fine job of keeping the EV Range at the set point. But with hills, accelerating at speeds below 60 mph, where the EV Range drops significantly it will not recover back to the set point even after hundreds of miles.

 

Not a counterpoint, as much as an observation and data point.

One of our 100 mile drives involves a long climb south out of Tellico Plains, TN. We most often have switched to HV @ 10 EV miles remaining. During that climb, the EV miles drop to around 6.x miles remaining. And the bees start stirring near the top of the climb.

But coming down the other side, EV miles do inch back up to 10, or even 11 or more, and hover around 10 or so for the rest of the trip home.

As an aside, it’s fun going down that same grade the other way - if we’re @ 10 EV miles at the summit, we’re @ 14 or 15 at the bottom. I usually go back to EV for awhile at that point until it’s back at 10.

Probably not a factor, but all this is in SPORT mode with 4 chevrons of REGEN. The one exception is backing off a bit on the REGEN to keep speed up on the long descent.

 

Picture being 1,000 words and all that, the climb I just referred to:



We do live in a beautiful corner of the world. And not by accident - I moved up here from Florida mainly for the wonderful motorcycling roads.