Just got my Clarity Plug-In a couple days ago and I have an efficiency question

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Agreed. While highway does use the battery faster it is because of wind resistance and no regenerative braking happening. I use EV mode all the time unless I'm going on a long drive beyond the capacity of the battery. At that point I selectively use HV to have it run only one time and when battery capacity matches my destination distance I go back to EV.

I'm lucky enough to be able to plug up at work with 220v. I only worry that I'm doing alot of charging from the same point up twice a day and the effects of that long term.
 
PHEV Newbie said:
If you watch the energy distribution screen in HV mode, often the flow of energy is from the ICE to the front wheels without charging the battery. If the white gear symbol appears, the clutch has activated to directly drive the front wheels. If the gear does not appear and nothing to going to the battery, the ICE is being used as a generator to directly power the electric motor. Presumably, it is bypassing the battery. In fact, I notice that the ICE is used as a direct generator for the traction motor or driving the wheels directly most of the time. It seems to primarily charge after range is lost (e.g., supplementing the ICE on long upgrades) and it needs to bring you back to the range when you activated HV.

To me, it makes sense to just stay in HV mode during road trips and not bother charging at charging stations. The gas mileage is really outstanding and do you really want to waste 2.5 hours at an out of the way charging station for each 40 minutes of run time (47 mile range at 70 mph)? On top of that, the cost of electricity at charging stations (if not free) tend to be very high, usually much higher per mile than the cost of gasoline.
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Where on the display does the gear symbol show up? I've not seen it.
 
Personally, I think those among us that spend a lot of time switching between modes are just wasting their time. It is stepping over dollars to pick up pennies. If your goal is to minimize energy usage, either, or even both, battery and gas, just slow down. Drive the speed limit EVERYWHERE! That one thing alone improved my mileage in my last 2 cars by 15%. I am always amused when driving on the highway at the posted speed limit and a Prius passes me doing 15 mph over the speed limit. Why did he (she?) buy a fuel efficient car if they’re going to drive like a maniac?

For me, I always use electric only until the car switches automatically to hybrid. I have never even felt the accelerator detent. In my regular routine driving, the only time I use hybrid mode is the return trip from work. It’s 37 miles one way to work, so roughly 10 miles of the return is still on battery. According to the mileage ratings, that equates to about 5/8ths of a gallon used per round trip to work. With three trips to work since my last (and only) fill up, that would mean I’ve used 26% of a tank. Corresponds to the gauge indication of 3/4s full.

As always, your mileage may vary, literally. But switching modes from EV to HV to HV Charge to try and outsmart the onboard logic just doesn’t make sense to me.
 
@Tailwind You can certainly let the car's logic do its thing and just drive without using the mode buttons - that's the beauty of the Clarity, it just works. However, it seems that someone else who has a similar distance daily commute as yours might benefit from changing to HV mode if there is a mix of both freeway and city driving. Is your home very close to the freeway, or is there still some local driving? If there is some city driving after you get off the freeway, switching to HV mode while you are on the freeway on the return journey can preserve enough of the battery charge so that last stretch of city driving can be done in EV (pretty much what @Dana Mitchell described in his comment). And you may find that you will end up using less gasoline overall if you only use the ICE during freeway driving while doing all city driving in EV mode, mainly because battery charge drains so much faster at highway speeds, whereas city and stop&go driving uses more gasoline.
 
Unless I've missed it, I didn't see the affect of the electric heater in any of the efficiency calculations. So how does that figure in the numbers?
 
PHEV Newbie said:
...(47 mile range at 70 mph)? On top of that, the cost of electricity at charging stations (if not free) tend to be very high, usually much higher per mile than the cost of gasoline.
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I can tell you this much, you'll never see 47 miles EV at 70 mph.

Tailwind said:
...As always, your mileage may vary, literally. But switching modes from EV to HV to HV Charge to try and outsmart the onboard logic just doesn’t make sense to me.
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Depends on usage Tailwind - if you are facing longer than commuting distances (like my recent 600+ mile round trips) where there are advantages to preserving EV distance at the destination - all HV to destination; EV at end point; HV/HV Charge back to home if you'll need EV at that end...

to each their own...
 
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jdonalds said:
I don't know the answer but I'll just add that if the car is in HV mode it acts like a regular Prius in that it constantly is charging the battery and using the battery along with the ICE. So for all hybrids the batteries are going through small charge/discharge cycles all the time. It seems like using Charge mode isn't any different except that it may use a stronger charge amperage than normal HV mode. But I'd count on Honda to get that right.
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In general, PHEVs are designed to allow the battery pack to provide as much as possible of the energy for driving, until the battery pack drops to a certain level. Below that, the car uses its gas motor to power a generator which keeps (or at least tries to keep) the battery from being further exhausted. IIRC in the Volt that level is 30%. I dunno what it is for the Clarity PHEV, but presumably it's approximately the same.

Turning on "Charge" mode on the Clarity should increase the level at which the car tries to maintain the battery pack. I'd be interested in seeing if someone can give us an accurate figure for that increased level; the percentage of full charge. For most cars I'd say just look at the instrument panel and see what the gauges report for the charge level, but there have been so many reports of the Clarity reporting range or charge level which is wildly off that it's obvious those gauges are not reliable.
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This is exactly what I do. Within range, I drive in eco mode, so all EV easily. Switch to normal if I need more boost. On a longer trip, switch to HV for the highway portion and maximize range of battery in city portions. Works perfect - ended up with an average of 3.5l per 100 km on a 250 km trip last week.


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Kendalf said:
If there is some city driving after you get off the freeway, switching to HV mode while you are on the freeway on the return journey can preserve enough of the battery charge so that last stretch of city driving can be done in EV (pretty much what @Dana Mitchell described in his comment). And you may find that you will end up using less gasoline overall if you only use the ICE during freeway driving while doing all city driving in EV mode, mainly because battery charge drains so much faster at highway speeds, whereas city and stop&go driving uses more gasoline.
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Right. In fact, that ought to be put into a FAQ somewhere.

No need to keep obsessively switching between HV and EV mode, but if you're going to drive beyond the EV range of the Clarity, then it makes sense to switch to HV mode for some or all of the highway driving, and preserve the EV range for where it will do the most good, which is at lower speed and/or stop-and-go driving.

I'm assuming here that the goal of most Clarity owners is to make as many miles as possible EV miles, rather than gas-powered miles. That also means that on the way back during a trip that will (or is likely to) go beyond the EV range of the car, switch back to EV mode as soon as you're sure you have enough EV miles to get there, even if you're still on the highway.

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Now if your goal, gentle reader, isn't to maximize the EV miles in order to minimize the amount of gasoline/petrol used by your car, if you bought your Clarity for a reason or reasons having nothing to do with reducing the amount of gasoline you burn, then this doesn't apply to you.
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dstrauss said:
For me, I generally use EV around town and on the loops (35-60mph ranges), and kick in HV at freeway speeds - reasoning - on those longer freeway trips I'd like to have EV available for in town driving. As for HV Charge Mode - it is pretty inefficient/nonexistent at in town speeds, but I will use it on the freeway occasionally to maximize that in town driving at my destination. Remember, recharge will only get you 57-60% of a full charge, then stop, and it will tell you this when you hit the max.

I always like @jdonalds advice - just drive and enjoy - the car will take care of (most) of the rest.
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Hmmmm...I knew I read all this somewhere earlier in the thread...:D:D:D
 
dstrauss said:
I can tell you this much, you'll never see 47 miles EV at 70 mph.
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I did 53 miles yesterday, virtually all highway, in EV mode at 50-55 mph.

When I got in the car on Friday morning, it said I had 51 miles EV range. It is about 3 miles through neighborhoods until I get on the highway, then 34 miles to the airport at 55 mph. Temperature was 38°F. When I returned yesterday afternoon, temperature was around 60°F and car said it still had 14 miles EV range. After 16 miles on the highway on the return trip, the engine came on for the first time.
 
Tailwind said:
I did 53 miles yesterday, virtually all highway, in EV mode at 50-55 mph.

When I got in the car on Friday morning, it said I had 51 miles EV range. It is about 3 miles through neighborhoods until I get on the highway, then 34 miles to the airport at 55 mph. Temperature was 38°F. When I returned yesterday afternoon, temperature was around 60°F and car said it still had 14 miles EV range. After 16 miles on the highway on the return trip, the engine came on for the first time.
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Is this your first EV car? We have had a Nissan Leaf for 7 years. (2 different cars). Here is what affects range in an EV. Hills and/or inclines. A/C on. Heat on. Speed. When you are driving, you may not be aware of inclines, but the battery knows. Our Clarity typically shows a range, after charging, of about 54 miles. Freeway driving at 55-65 mph does not seem to affect it much. Driving the canyons in Los Angeles is interesting. Uphill the range takes a dive, but it recovers on the way down.
 
bfd said:
There will be many right ways to think about this. Electricity isn't as efficient as using gas at freeway speed. Mostly, the system will take care of that in "normal" mode. You can force it to use more electricity in EV mode, and it'll do that. I suspect that mode just decouples the motor from ICE and burns electricity w/o replenishing it via ICE. HV does just the opposite. And in normal this is "automatically done". Sport seems to change the accelerator algorithm. It doesn't seem to add power as much as it changes how much pressure you need to apply to get at that power. As a result, it will eat up more fuel (Electric and gas). I have tried, and I get the same results by simply flooring the go pedal to the detente. OK, sometimes I fail because I overshoot it. LOL
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In actuality, electricity is still more efficient than using gas period. I can still get close to 100 mpge driving highway miles. However, the problem with electricity is the energy storage. The vehicle has a 17 kWh battery, and after draining it to 9-10% and recharging, it appears we can use 14.3 kWh of this. 14.3 kWh of energy is equivalent to only .44 gallons of gasoline (a gallon of E10 has 32.78 kWh of energy). After looking at those numbers, it's clear why it is best to use HV for sustained highway driving. If you can complete your trip, even with highway driving, within your EV range, then it is still best to use electricity. At some point down the road battery prices will drop enough so that you can get a 75 kWh or 100 kWh (like those found in the Teslas) for a more practical price. At that point, highway driving with electric would be more feasible. We aren't there yet.
 
Maybe our case is unique. Our house has solar power. It costs nothing to charge our EV or PHEV. There are studies that show that EV is cleaner than gas or hydrogen. Bottom line: Use EV whenever you can until it runs out.
 
uks-transport-environment-says-that-electric-cars-are-the-most-efficient_100626958_l.jpg


from the UK-based Transport & Environment
 
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