1. Attachments are working again! Check out this thread for more details and to report any other bugs.

How long does the battery charge last?

Discussion in 'Gen 3 Prius Main Forum' started by TJE1020, Apr 14, 2010.

  1. TJE1020

    TJE1020 New Member

    Joined:
    Apr 14, 2010
    5
    1
    0
    Location:
    New Jersey
    Vehicle:
    2010 Prius
    Model:
    V
    I've just purchased my first Prius exactly 20 days ago. I'm starting to get the hang of it but it still seems like I'm doing something wrong or maybe I'm over analyzing what I'm doing. For an example the battery is nearly fully charged I'm driving in traffic stop and go but the battery drains in about 15-20 minutes. Is that normal?

    Or accelerating. Do you accelerate within the ECO bar until you reach your travel speed and then cruise? Whenever I see a Prius next to me at a light they seem to move at a better pace then I. Maybe they don't care about more MPG?

    I'm averaging consistently about 50 MPG but I feel like I could get more considering I work in the city where the electric motor should be at its best.
     
  2. jdcollins5

    jdcollins5 Senior Member

    Joined:
    Aug 30, 2009
    5,131
    1,338
    0
    Location:
    Wilmington, NC
    Vehicle:
    2010 Prius
    Model:
    III
    First, welcome and congratulations on your new purchase.

    Do not worry about the battery charge. The car and the computers will do a good job of taking care of this for you.

    I have found that I have to accelerate well in to the power area in order to keep up with existing traffic. I have also found that if I accelerate briskly up to speed rather than slowly I actually get better mpg. Quicker to accelerate then quicker to glide.

    Most of the experts on here will tell you that using the electric motor is not the most efficient. The electric motor uses battery that will have to run ICE to recharge, thus losing efficiencies. I will need for one of them to explain this better than I can.
     
    1 person likes this.
  3. kasnova

    kasnova New Member

    Joined:
    Mar 28, 2010
    19
    3
    0
    Location:
    California
    Vehicle:
    2010 Prius
    Model:
    II
    I have had the same experience as jdcollins5. I tried staying in the green eco area while accelerating on my first tank and only got about 50 mpg. On my second tank I didn't worry about going into the power area when I needed to get up to speed and I got 55mpg.

    From my understanding, if you're going to use the engine, you should just go all out rather than just a tiny bit. You can use the instant mpg gauge to help guide you on this. You'll notice that it doesn't change that much between the higher eco areas compared to into the power zone. So by keeping it in the eco areas longer, you're in the bad mpg zone longer and thus getting worse gas mileage.
     
    1 person likes this.
  4. Philosophe

    Philosophe 2010 Prius owner

    Joined:
    Jun 2, 2009
    437
    72
    1
    Location:
    Montréal, Québec (Canada)
    Vehicle:
    2010 Prius
    Model:
    N/A
    Some tricks:
    • Remember than your only real energy source is the petrol in your tank, thus the engine. With that in mind, avoid using the EV button; most of the time it will increase your gas consumption.
    • Use brisk accelerations and then glide (lift your foot and allow the engine to turn off), keeping yourself in the first ¼ of the ECO part of the HSI display, using limited energy from the battery to keep your speed. If you can't, accelerate briskly and glide again (pulse and glide technique).
    • Remember that a cold engine is inefficient: avoid pushing the engine too much in the first minutes, until it gets hot enough to be efficient (your commute may or may not allow much flexibility here...). By itself, the HSD uses mostly the electric motor during this short period of time, unless you push the accelerator toward the end of the ECO part of the HSI display.
    • Avoid touching the brake pedal by planning your accelerations/decelerations; when you need to brake, try to keep yourself inside the CHG part of the HSI display (it is suspected that if you push the brakes further, your will be using friction braking and losing energy).
    • On the highway, reduce your speed (energy required to displace air increase to the square of the speed) and use cruise control to keep a constant speed.
    • Stay in ECO mode, which, along with a different gas pedal mapping, will do some nifty tricks to enhance fuel economy (prevents the cabin heater to remove too much heat from the engine when cold, throttles down the A/C power, recirculates cabin air more often, etc.).
    • If you are a MPG freak, you can also turn off the cabin heater to prevent it from running the engine to create heat (concerns only heating, A/C is quite efficient by itself).
     
    1 person likes this.
  5. vinnie97

    vinnie97 Whatever Works

    Joined:
    Mar 20, 2010
    1,430
    277
    0
    Location:
    Somewhere out there
    Vehicle:
    2018 Tesla Model 3
    Model:
    N/A
    ^Doesn't accelerating briskly cancel some of the benefits of the glide technique? Why not just use the same technique but with gradual acceleration?
     
  6. Philosophe

    Philosophe 2010 Prius owner

    Joined:
    Jun 2, 2009
    437
    72
    1
    Location:
    Montréal, Québec (Canada)
    Vehicle:
    2010 Prius
    Model:
    N/A
    It is related to the efficiency map of the Prius engine (see this thread). The engine is more efficient at some RPM. Also, my guess is that by accelerating faster, you allow for longer gliding.
     
  7. mmurphy

    mmurphy Junior Member

    Joined:
    Jul 22, 2009
    42
    6
    0
    Location:
    Akron, OH
    Vehicle:
    2010 Prius
    Model:
    II
    The effeciency of the gas engine is greatest in the top quarter of the HSD (the area just below Power). So, you get the most power out for gas used when you accelerate relatively briskly, with the HSD bar just below Power.
     
  8. nerfer

    nerfer A young senior member

    Joined:
    Mar 1, 2006
    2,505
    232
    28
    Location:
    Chicagoland, IL, USA, Earth
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    Actually, because of the CVT (okay, planetary transfer whatzit), the engine can choose the proper RPM to be in its prime engine loading. I don't have a 2010, so I can't really speak about ECO vs. Power levels, but moderate acceleration works best - too little and you may be falling back to battery only, which looks good for a short period but not overall because the batteries need to be recharged at some time, which ultimately will require the gas engine. That could also be why the OP's battery level falls so much. Too much acceleration will also pull in battery power to assist.

    What's more important is gliding and coasting when possible. This is hard to do in stop and go traffic, but if you can read the lights or prepare for stop signs without being a road hazard, then you can really improve your mileage.

    Kasnova - the second tank is probably going to be better than the first no matter what (first tank probably has some test drives on it with sudden starts and stops). You need a couple months to really start averaging out results and trying some different techniques.
     
    1 person likes this.
  9. qbee42

    qbee42 My other car is a boat

    Joined:
    Mar 2, 2006
    18,058
    3,073
    7
    Location:
    Northern Michigan
    Vehicle:
    2006 Prius
    Using terms like "brisk acceleration" and "moderate acceleration" is like asking someone what blue looks like to them. To avoid these quantitative problems, let me give you a qualitative description of why people say to use brisk acceleration:

    All gas engines are more efficient at some speeds than others. Low power levels are always inefficient for a normal gas engine since the intake air must be pulled through a closed throttle plate. This increases what is called pumping loses. Likewise wide open throttle (WOT) is also generally inefficient due to trade-offs that are used to get extra power from an engine.

    The key to good engine efficiency is to stay away from the extremes: low power levels and high power levels. The Prius has an advantage with its CVT, so the engine can run at any speed ordered by the control system. Still there are limits. At low power levels the engine will run at a more efficient power level and use the extra power to charge the HV battery. This is more efficient than running at a lower power level, but the charging/discharging cycle still wastes energy. The conversion of the extra energy to electricity and the storage of that electricity in the HV battery does not come for free.

    Better then to run the engine at its most efficient level and store the extra energy in the mass of the car as kinetic energy, or in other words, momentum. Use the engine efficiently to speed up, and then use the stored momentum of the car to coast. This is the notion of pulse and glide in a nutshell.

    Tom
     
    1 person likes this.
  10. nerfer

    nerfer A young senior member

    Joined:
    Mar 1, 2006
    2,505
    232
    28
    Location:
    Chicagoland, IL, USA, Earth
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    That's all fine and dandy, but you got sidetracked with why moderate acceleration is good, not what moderate acceleration is. I think the OP wants to know what that looks like on his dashboard. I don't have a good answer there, so I was hoping your qualitative answer would help...
     
  11. Philosophe

    Philosophe 2010 Prius owner

    Joined:
    Jun 2, 2009
    437
    72
    1
    Location:
    Montréal, Québec (Canada)
    Vehicle:
    2010 Prius
    Model:
    N/A
    Acceleration kept at the end of the ECO zone of the HSI. Some will say that it isn't bad to also go into the beginning of the PWR zone.
     
    1 person likes this.
  12. jdcollins5

    jdcollins5 Senior Member

    Joined:
    Aug 30, 2009
    5,131
    1,338
    0
    Location:
    Wilmington, NC
    Vehicle:
    2010 Prius
    Model:
    III
    The way that I would describe brisk acceleration is to watch the CONS mpg as you are accelerating. At what acceleration rate does your mpg decrease the least before you reach your speed and begin to glide. Then watch to see how quickly you can recover the mpg back to the point you were prior to the previous stop. I have found that if I accelerate to the right side of the power zone that I will recover my prior mpg quicker than a slower acceleration in the ECO zone.
     
    2 people like this.
  13. TJE1020

    TJE1020 New Member

    Joined:
    Apr 14, 2010
    5
    1
    0
    Location:
    New Jersey
    Vehicle:
    2010 Prius
    Model:
    V
    On my way home I put together a little of what everybody posted and I'm seeing a difference. I think I was trying too hard to keep the car in the first half of the bar instead of benefiting from the glide aspect. I was wasting all the energy on acceleration think I was doing a better job. I'm halfway through tank two so lets see what happens.
     
  14. Penny's Dad

    Penny's Dad New Member

    Joined:
    Dec 2, 2009
    421
    46
    0
    Location:
    Orlando Fla
    Vehicle:
    2010 Prius
    Model:
    II
    I like to see how often I can keep the milage indicater (to the right of the digital speed read-out) reading "100". I find this is best accomplished using the pulse and glide technique spelled our in the great posts above. Also breaking way in advance and borrowing brake energy to charge the battery is a great way to spare the engine from having to do the job.