Battery capability

Discussion in 'Gen 4 Prius Fuel Economy' started by I'mJp, Mar 6, 2016.

  1. I'mJp

    I'mJp Senior Member

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    The Lithium-Ion battery has a spec of 207.2 volts and capacity if 3.6 ampere hours.

    So that makes it a 745.94 watt hour battery.

    MG2 has an output rating of 53 kW. I'm going to assume the motor is 100% efficient.

    Dividing, and converting to seconds, that gives the battery 50 seconds of 53kW with 100% efficiency

    That doesn't seem very long.

    How many hp does it take to keep a Prius rolling, on a smooth flat and level, say at 40 mph ?
     
  2. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    Typically, Toyota does not charge above 80% nor discharge below 40%.
     
  3. bisco

    bisco cookie crumbler

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    you're way overthinking this. what are you trying to determine?
     
  4. Trollbait

    Trollbait It's a D&D thing

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    That's with the NiMH pack in order to prolong life. Li-ion can use a wider range of SOC without risking battery life.
    M/G2 is not going to be working alone with high power demands, nor will it be using the battery alone. The ICE will be running, and M/G1 supplying power to M/G2.

    I've heard 15hp to 30hp to cruise at 60mph. There is an original Insight with a fifth wheel. It is tucked up like a plane's landing gear, and it pops down when the driver turns off the ICE at speeds around 40mph. It is electric powered, and only has a 5hp motor. So the Prius will need very little energy to maintain speed at 40mph; specially if the driver can make it glide during sections.
     
  5. I'mJp

    I'mJp Senior Member

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    I can cruise (flat and level) for many minutes on battery, 15 - 30 hp which is 11 - 22 kW would give 2 minutes, maybe double that for 30mph.

    My assumption of 100% efficiency is incorrect (bad assumption, but correct answer ), in that the rated 53kW of mg2 is the measured output of the motor, after losses.

    So it does make sense.



    Just checking the specs, seeing if they match my observations.

    merged

    I know that that is true for the gen 3, but I don't know the scan gauge codes for the gen 4 for the Lithium battery, so I'm unable to see what the ( possibly new ) range is.
     
  6. bwilson4web

    bwilson4web BMW i3 and Model 3

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    1. Download the "Test Car Database" from EPA.gov (I use Google to find it.)
    2. Identify the matching car and get the three roll-down coefficients (not the dyno settings!)
      1. Target Coef A (lbf)
      2. Target Coef B (lbf/mph)
      3. Target Coef C (lbf/mph**2)
    3. Use the following formula:
      1. (mph * (Coef_A + (mph * Coef_B) + (mph * mph * Coef_C) ) / 375
    NOTE: this does not include the electrical overhead that ranges in the 450W range or about 450/745 hp.

    Bob Wilson
     
  7. Vman455

    Vman455 Senior Member

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    Or, using this calculator for a quick-and-dirty estimate with Gen 4 Two specs, somewhere around 6-7 horsepower, or 4-5 kW at 40mph on a level road with no wind.
     
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