Clarity performance when battery is depleted

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ProspectiveBuyer

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I've been driving my Clarity for close to 3000 miles and have managed to avoid using gas for most of that time. I still have a nearly full tank from when I purchased the car. And for the brief period I needed to use the gas engine on a previous occasion, the car handled reasonably well. Though the terrain was fairly flat. But last night, I was unable to charge and was driving home on gas. Generally, the car performed well. Until I had to climb a hill over a sustained period of time on the way home. That's when it seemed to struggle as the grade steepened. This was one of my main concerns about the Clarity and while it wasn't horrible, I was disappointed. I know at some point, driving on the gas engine is going to be unavoidable. But at this point, I'm gonna be even more mindful of keeping the car charged at all times when possible. Just wondering what others' experience and reaction has been to this.
 
I live in an apartment building and have no regular access to charging, so about 80 to 90% of my driving is in “Forced HV” mode. In my experience, the car behaves exactly the same in this mode as it does in EV, with the only difference being the variable engine noise. Sometimes the engine is hardly noticeable, but occasionally if the battery drops below a certain threshold (~6 or 7%) it’ll rev a bit louder.

I’ve never experienced the loss in power reported by others on this forum, even over long trips on relatively steep hills. As I understand it, the only situation where the Clarity will actually *drive* any differently is on a prolonged hill where the battery depletes to the point where it’s only the engine supply current to the traction motor, which might not be sufficient to meet the full power demands. Again, I’ve never experienced this firsthand. On your hill, was the car actually struggling or did it just rev louder? Higher revs are to be expected sometimes in this car, where the engine is usually a step removed from powering the wheels.


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This doesn't surprise me - it's the reason I switch to HV when battery reaches 50%, unless I'm within EV range of a charger. HV works best when you have some battery.
 
UncheckedException said:
I live in an apartment building and have no regular access to charging, so about 80 to 90% of my driving is in “Forced HV” mode. In my experience, the car behaves exactly the same in this mode as it does in EV, with the only difference being the variable engine noise. Sometimes the engine is hardly noticeable, but occasionally if the battery drops below a certain threshold (~6 or 7%) it’ll rev a bit louder.

I’ve never experienced the loss in power reported by others on this forum, even over long trips on relatively steep hills. As I understand it, the only situation where the Clarity will actually *drive* any differently is on a prolonged hill where the battery depletes to the point where it’s only the engine supply current to the traction motor, which might not be sufficient to meet the full power demands. Again, I’ve never experienced this firsthand. On your hill, was the car actually struggling or did it just rev louder? Higher revs are to be expected sometimes in this car, where the engine is usually a step removed from powering the wheels.


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The car seemed to be straining a bit more to get up the hill. It made it but I could tell it didn't have the pickup that it normally has with battery assistance.
 
ProspectiveBuyer said:
The car seemed to be straining a bit more to get up the hill. It made it but I could tell it didn't have the pickup that it normally has with battery assistance.
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Is it that or could it be that you are consciously restricting yourself from stepping on the pedal because you know you were driving on gas?
I run out of EV range all the time toward the end of my commute (but not 0% on battery), and I have some steep hill to climb before reaching home. I usually find the car has more power going up the hill than just EV tho
 
This happened to me also when climbing a long uphill grade. Now I just use hv charge mode for about 20 minutes before I get to the hill. This allows the battery to recharge to 58%. The fuel economy goes down but the car performs much better.
 
ProspectiveBuyer said:
The car seemed to be straining a bit more to get up the hill. It made it but I could tell it didn't have the pickup that it normally has with battery assistance.
Click to expand...
There's a mountain grade outside of town I take every so often. Steep and long enough that semi-trucks slow down to about 25 mph going uphill. On EV only (with a good charge), I can fly up no problem but the battery is much depleted when I get to the top. In HV mode with a low charge (not even depleted, this happens at less than 40%) the ICE strains as if it is trying to conserve what's left of the battery. With a significant charge (50-60% and higher) in HV, it combines ICE and battery seamlessly and I fly up the hill (60 mph, or higher if I wished) with the ICE purring quietly. Here, the battery gives up a good number of miles of range at the top but I notice that the ICE keeps running to recharge the battery even though I'm now going slightly downhill. It will recharge the battery back to where it was before the grade. Lesson is to make sure you have a good charge before any mountain grade, even if it's rather short, if you don't want to strain the ICE. The car has ample power in the drive train but you have to manage the stored power properly. Be sure you don't deplete the battery otherwise you are completely reliant on the small 108 hp engine to generate electricity to propel a very heavy vehicle up an incline. In the flats, the ICE is plenty to drive the car at highway speeds. For mountain grades, it needs the combined power of the ICE and battery. The algorithm seems to be rather conservative so it won't tap the battery unless there is ample charge left. Without an ample charge, you're gonna be stuck in the right lane behind semi-trucks going 25 mph.
 
I drove 190 km yesterday (virtually all of it highway) with a depleted battery as I didn't have the option of charging before I left. I had no issues at all driving at 115-125 km/hr on the 401/416 highways. Granted there were no long steep hills, but with the rolling hills on my drive I never experienced any sort of power loss / speed loss / angry bees. My fuel economy obviously suffered (averaged 5.7 l / 100 km on this drive), compared with driving with a battery, but even this mileage was a lot better than my previous car (Prius V) has done on the same drive/conditions. Thus while not ideal, I don't think there are any issues with driving in pure gas mode if needed.
 
I routinely drive on pure HV once I've depleted all of my EV and I don't notice a thing. I'm on straight freeway, never a hill, so that probably makes the difference. However, I can honestly say that with the noise of the freeway I barely know if I'm in EV or HV mode. It's really been a non-issue for me.
 
Here are my observations as I've been running my car each day from full to depleted and letting the engine kick in on it's own. After the EV range goes to zero (two bars showing), the engine starts and I watch the vehicle energy screen. My speed is pretty level at 65mph. The engine is begins at low RPM's for about 4-5 minutes and the energy screen shows the car being powered from battery and engine, this seems to be engine warmup period. Then the engine begins to rev higher for another 4-5 minutes with the energy screen showing most times the car being powered by the engine and power flowing back to the battery, this seems to be the car getting the battery back up to the energy level it had when EV range went to zero. Then after that the revs go down and it shows the gear icon, engine off and engine on in the more normal HV pattern. You can noticeably hear the engine during the high-rev period but nothing that concerned me. When I enter HV with EV range to spare, it does go through the warmup cycle and then gets the HV back to where it started but does not seem to rev as high as when EV is zero. The drive is generally flat for this observation.
 
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