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kWh for HV ?

Discussion in 'Prime Fuel Economy & EV Range' started by Marine Ray, Dec 8, 2021.

  1. Marine Ray

    Marine Ray Senior Member

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    Excuse my ignorance but math was never my strong suite - I understand the upper and lower buffers. However, can't get a handle around the math - 8.8 kWh is full capacity, 6.6 kWh for EV. Upper and lower buffer (not used I presume) would equal about 2 plus kWh. Where's the kWh for HV?
     
  2. Tideland Prius

    Tideland Prius Moderator of the North
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    6.6kWh includes the hybrid portion. The EV portion is about 5.2-5.3kWh IIRC. This is the net. (What you see from the meter at the power outlet will be closer to 6kWh due to charging losses and heat).
     
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  3. vvillovv

    vvillovv Senior Member

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    To the mathematicians and engineers the losses are the interesting part, because they're everywhere along the supply chain, and also because nothing is %100% efficient, at least nothing humans have found yet.
    The electrical loss I'm most familiar with is resistance, though there are others like chemical conversions in the batteries and electromagnetic in the motors.
    Some older PC members compared notes and came up with the general consensus that the prime gets around 5.5 kWh to the wheels. 6.6 kWh at the plug and 8.89 kWh capacity. Or something like that. And listed the losses so it was fairly easy to understand,

    I'm still not sure how far down the voltage curve the prime is configured for, but EV mode triggers the engine at around 325 volts, with about a 5 volt buffer, so very minimum voltage is 320 volts and that's only for a few seconds and the rebound needs to be able to jump back up to 325 volts when the load is removed. It works a bit different under higher loads down around 330 volts, due to the voltage depression under the load making the ICE fire early sometimes if the load is high enough.

    I printed that gobble de gook above, kinda to get it straight in my own mind too, form what I've seen happen in my Prime while keeping as close an eye on DrPrius as I could when getting down near the trigger voltage for the ICE startup. at times going uphill as well as going downhill and on the flat.
    And, also so I'll remember to check what it looks like in HV mode, since I'm using the ICE a lot more now than ever before and I'm not as fanatical as I used to be about running EV only while driving locally.

    DrPrius pits my Pimes EV range between 373 volts full and 325 volts (or 320 volts for a few seconds, depending on load and voltage rebound variables) where the ICE triggers. That calculates or should calculate to around 5.5 kWh, as I'm no mathematician either.

    Loads for calculating the conversion (in my case) are almost always uncommonly low and as mentioned above the behavior is different with normal and higher loads, in my experiences, anyways.

    Keep in mind that hybrid computers adjust or have the ability to adjust to driver input and each individuals normal driving patterns, whatever they may be. I haven't seen anyone post yet about exactly how long Prius keeps and or uses / calculates history data. So that to the best of my understanding is an unknown variable, per manufacturers implementation / programming.
     
    #3 vvillovv, Dec 9, 2021
    Last edited: Dec 9, 2021
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