HV Charge question

Discussion in 'Clarity' started by brentac, Jul 25, 2018.

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  1. brentac

    brentac Member

    I don’t remember the last time I actually used HV charge mode but i was curious, does anyone know the rough MPG of gas in Charge mode vs regular HV mode? I have to assume it’s worse but couldn’t find the numbers.
     
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  3. Steven B

    Steven B Active Member

    I've not noticed anyone post data on this. I've used the mode a couple of times but since fill-ups (or even system trip recordings) didn't book end the mode exclusively, the economy could not be reliably obtained.
     
  4. neal adkins

    neal adkins Active Member

    Mine hovered just below or at 30mpg
     
  5. kcsunshine

    kcsunshine Active Member

    Is it okay to use the HV charge mode while parked? I know the manual says it is not recommended for city driving or driving slow. Sometimes you have no opportunity to charge (or call it a lack of planning) and want to tackle the hills. I don't see why you can't use the engine to charge up. There is no driving load on the engine.
     
  6. KentuckyKen

    KentuckyKen Well-Known Member

    There may be a reduced airflow issue and possible over heating with the car sitting still and high ICE rpms. Be sure to monitor the temps if you try this.
     
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  8. Viking79

    Viking79 Well-Known Member

    How big of hills are you talking? I had no issue at 80 mph over I-80 between Cheyenne and Laramie (about 6000 to 8600 to 7200 feet) without HV charge (I turned it on, but too late). The thing to remember is if you deplete your battery reserve the car goes from like 180 to 200 hp to around 100 hp peak. It still has a fair amount of power for driving, but might start slowing down in some situations. For comparison, the Volt 1 had like 80 hp and my i3 Rex has like 34 hp on gas only.

    To calculate gas mileage in HV Charge is tricky as you really should add on the added electrical miles. To do this, run the battery completely down (2 bars). Reset trip A. Run the engine until HV charge is done (or however long until it has recharged some range). Drive off the added EV miles. Your MPG should be accurate for trip A (my MPG meter reads about 5 to 10% high). The first part of the cycle on gas only will be like 20 or 30 mpg. The added electrical miles will make it go back up to around 40 mpg more or less depending on situation.
     
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  9. neal adkins

    neal adkins Active Member

    Common sense tell me that it just is not feasible. You will get more efficient charging at highway speeds. The computer should automatically over ride any mode that would cause damage. So choosing hv charge mode should be fine or the manuel would tell you not to do it.
     
  10. kcsunshine

    kcsunshine Active Member

    So I tried it to increase one bar and it worked fine. The engine was barely noticeable which felt like a normal idle.

    The hills I'm talking about are local hilly roads. I posted in another thread that the car struggled in a small town with hilly roads once I ran out of charge. It was driveable but I had to stomp on the pedal and it was a bit sluggish.
     
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  11. JCEV

    JCEV Active Member

    I find HV mode has the most power available so I don't think you have less power but actually more in this mode. It generates the electricity for the electric motor at 181hp plus whatever is left moves overall power up to 212 vs just 181 on electric only. In my opinion you don't need any EV in HV mode. Think of HV as Prius mode .

    This is also why you get the buzzing in HV going up a hill , it needs the 5000 rpm to power the electric motor at a high rate and drive the wheels
     
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  13. insightman

    insightman Well-Known Member

    When the battery is supplying all the electricity, the motor can generate only 121 hp. When the engine is powering the starter motor/generator to supplement the battery, the motor can generate its full 181 hp. The Engine Drive mode must be engaged to achieve the full 212 hp. That's the only time the power of the engine can be added to the power of the motor (but the 103 hp engine and 181 hp motor don't peak at the same time).
     
  14. I haven’t tested it, but in all my reading, 30 mpg seems to be the popular answer to the OP’s question.
     
  15. KentuckyKen

    KentuckyKen Well-Known Member

    I think our HV mode is better than the Prius since on the highway, our ICE doesn’t have to run all the time.

    If you want to avoid the buzzing angry bees and always have plenty of power for hills, all you have to do is not let the HV battery completely deplete down to 0 EV range and 2 bars.
    For level roads, moderate acceleration, and normal speeds you can get by with using up all your charge and letting the car automatically switch to HV.

    But on the highway, and especially with hills and higher speeds, the car likes more than the 2 bars to be able to cycle through all of its possible power flows to be able to deliver the most efficient, quiet, and required power.

    On a recent 500 mile round trip with both Interstate at 70mph and hilly 2 and 4 lane very hilly roads at 60-70mph I started in HV with a nearly a full charge. I watched the powerflow cycle though battery only, battery plus generator, regen, generator charging battery, engine direct to wheels, all seemlessly done as far as felt power and drivability. I got 49 mpg and lost only one bar of EV so the mpg was not inflated by using charge. Some times I would see the charge/EV decrease by as much as ~3 bars/15m but then gain it back as the computer decided when use the battery and when to recharge it. Also I have an hour meter and calculated the ICE ran about 2/3s of the trip and cycled on and off repeatedly and rather frequently.

    Best of all, I never heard the buzzing angry bees! Before this trip, I had to slow or stop the car and turn off the AC to be able to hear the ICE idling and only once on my first fairly level Interstate trip did I hear it make kind of a fast idle in HV. On this trip at the end of a very long, steep hill, the ICE did rev up to a low to medium hum but not the buzzing angry bees. But at no time did I ever experience a loss of power.

    So bottom line, you need some charge in the “bank” for the algorithm to be able to use all it’s possible powerflows in the most efficient and quiet manner. I would suggest switching to HV on highways before you run out of charge, say around 1/3 to 1/2 unless you know you’ve got mountains ahead and then I’d want a full charge by switching early. When you run down to 2 bars ans 0 EV, you can run into situations where the car is limited in what powerflows it can chose and you’re more likely to get the angry bees and driveability issues.

    And the only use for HV Charge I can see would be if you are on a highway and approaching mountains with not enough charge.
    This is the best car on the road and I want to end the angry bees for all.
     
  16. Steven B

    Steven B Active Member

    Yet more customization that we'd like to set as system preferences: Allow the user to establish setpoints (Battery SOC) at which 1) the vehicle always switches to HV mode (but which you can override with a press of the button), the vehicle switches to HV Charge mode (again, overriddable), and 3) the system stops charging when plugged in.

    If only this vehicle could be tweaked like i3s.
     
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  17. neal adkins

    neal adkins Active Member

    I had about 80 to 85 percent charge and was climbing up a long hill (about 2 or 3 miles) at 5 or 6 percent grade.i was in hv mode and the ice was racing at very high rpm. Im not sure why it didnt just use the battery more. I felt like it was struggling. I was at around 3800 feet elevation. It didnt seem to have the 212hp wich should have easily handled the climb. Any comments appreciated.
     
  18. Viking79

    Viking79 Well-Known Member

    Did it just "Feel" like it was struggling? Or was it just loud because it was revving high?

    I drove up a long 5 or 6% grade (I-80 east of Laramie towards Cheyenne) at 80 mph (7,000 to 9000 feet approximately). However, I started on battery only and after a couple minutes the engine started as I believe the battery got too hot from putting out so much current. Yes, the car does rev to 5000 rpm or more but it still had acceptable performance, I was able to slow and re-accelerate easily). Maybe this was due to me still having battery power though. I assume you had more than 2 bars battery when you started the climb?

    Part of the problem with the "angry bees" is people aren't used to CVT transmissions. The car will rev at a specific RPM and change the gearing accordingly (The Clarity does this with ratio between two electric motors). So in the Clarity that means jumping to 5200 RPM and staying there as you change speeds. I did a 0-80 mph run at 2 bars and it literally revs to over 5000 RPM at very low speeds and stays there the entire run making a constant drone.

    This makes it sound like "angry bees" but is really just typical of any engine with a CVT as it goes to the most efficient point for what you are trying to do (accelerate up a hill or doing 0-80 mph run). The point is it sounds like it is straining, but really isn't, it is running at high RPMs to generate power. The weird part with the Clarity is it will do this at low speeds sometimes if it is replenishing the battery buffer.

    (edit: I edited this a few times, never like what I write the first time)
     
    Last edited: Aug 1, 2018
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  19. neal adkins

    neal adkins Active Member

     
  20. insightman

    insightman Well-Known Member

    212 hp is available only when the gear icon is visible in the energy-flow diagram (Engine drive mode). When the engine is at high RPMs, it is powering the starter motor/generator to generate as much electricity as possible to supplement electricity coming from the battery. In this mode (HV drive mode), 181 hp is available. When the engine is off and your Clarity PHEV is powered by the battery only (EV mode), 121 hp is available.

    I have never personally experienced hearing our Clarity's engine at high RPM, so I can't provide any advice regarding the struggling you felt. My 2006 Insight struggles when it uses up its small battery on a long hill, so I know what struggling feels like. It will be interesting to see if your Clarity performs the same every time you tackle that grade.
     
  21. neal adkins

    neal adkins Active Member

    You are correct. It actually did maintain the speed but seemed to be working harder than nessacary. I did have around a near full charge 80 percent or more.
     
  22. neal adkins

    neal adkins Active Member

    It did actually maintain the 65 to 70 mph but the ice was at a very high rpm. So it was more loud than actually struggling as i stated. Seemed strange to me.
     
  23. kcsunshine

    kcsunshine Active Member

    I haven't driven on a long uphill yet but I think you should put the car in normal or sport mode. Having the car in HV mode means it tries to maintain the charge level. That means the ICE is trying to generate enough electricity to charge the battery while the electric motor is using it up. After you get over the hill, then you can put the car back into HV or HV charge mode. If the battery level fell below 58%, then HV charge mode is not going to bring you back to 85%, only up to 58%.

    I would do this on a long drive:
    If the battery is above 58%, drive in HV mode.
    If the battery is below 58%, drive in HV charge mode.
    When going uphill, turn off HV mode.
     
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