Real vs. Nominal Prime Battery Capacity

Discussion in 'Prime Technical Discussion' started by Tideland Prius, Sep 27, 2016.

  1. Tideland Prius

    Tideland Prius Moderator of the North
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    So the nominal is 8.8kWh

    What's the real capacity?

    If we take the average of 120mpge stated at NYIAS and 22 mile range.

    That means:

    120 miles per equivalent gallon of petrol,
    = 120 miles per 33.7kWh of energy content
    = 3.56 miles per kWh or 28kWh/100 miles

    22/3.56 = 6.17977 ~ 6.18kWh

    So the PHV portion is approximately 6.18kWh.

    The Li-Ion battery probably isn't the same compound as the one in the hybrid but the one in the hybrid is rated at 0.7kWh for reference.

    Did I do the calculations correctly?

    I guess we'll know once people start deliveries and charging their cars and get a readout from the meter.
     
  2. bisco

    bisco cookie crumbler

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    can you do the same for pip? i have no idea what you're doing there.:cool:
     
  3. JamesBurke

    JamesBurke Senior Member

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    6.18/8.8=70% 85%soc to 15%soc ?
     
  4. Tideland Prius

    Tideland Prius Moderator of the North
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    95 miles per equivalent gallon of petrol,
    = 95 miles per 33.7kWh of energy content
    = 2.819 miles per kWh or 35.5kWh/100 miles

    11/3.56 =3.902 ~ 3.9kWh

    Of course I'm simplifying and ignoring that 0.2 gal of petrol used when the engine kicked in when I used the 11 miles blended range.

    So, using the EPA's sticker of 29kWh/100 mile electric consumption

    [​IMG]

    We go back to the 3rd equation and work backwards

    29kWh/100 miles = 3.448 miles per kWh

    11/3.448 = 3.19 kWh

    The real capacity is found to be 3.4kWh so it's reasonably close. That 0.21kWh could be the difference between 6 bars and 8 bars on the hybrid portion (i.e. if the person charged while the car was maintain 6 bars which a Prius normally does)


    Perhaps. It might be larger or smaller depending on the final EPA numbers. I was just using the estimates from NYIAS. The PiP used 77% of true SOC (3.4kWh/4.4kWh)
     
    #4 Tideland Prius, Sep 27, 2016
    Last edited: Sep 27, 2016
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  5. bisco

    bisco cookie crumbler

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    wow, so you're saying prime usable battery might be slightly less than double?
     
  6. Tideland Prius

    Tideland Prius Moderator of the North
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    Which doesn't make sense, right? They said double the range. So either the 11 miles is more like 9 or 10 miles (officially rated IF the Prius never fired up the engine over the entire test) OR as other members have speculated, it's more than 22 miles.

    Prime "Auto-Blending" Mode could yield > 22 miles EV | PriusChat

    (US estimate says 22 miles, Europe says 50km but Japan says "more than 60km". Why is Japan different? Why doesn't Europe say "more than 50km"?. Why doesn't TMS say "more than 22 miles"? The PiP was rated at 26.8km in Japan so 2x that = 53.6km. If we use 60km as stated, then the % increase is (60/26.8=2.2388x). If we apply that to 11 miles, that's 24.6 miles. If we apply it to 15.5 miles (UK estimate for PiP), that's 34.7 miles or 55.5km.

    I stated that back in July
    Prime "Auto-Blending" Mode could yield > 22 miles EV | PriusChat


    Also, Consumer Reports did get 28 miles. I don't know if they were driving it normally or driving it hard like in their tests.
     
  7. bisco

    bisco cookie crumbler

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    what about improved chemistry and gen 4 hsd efficiency?
     
  8. Tideland Prius

    Tideland Prius Moderator of the North
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    Exactly. I mentioned that in that thread I linked about. It seems odd they only talked about the battery (2x the battery capacity = 2x the range). But what about all the efficiencies gained with the Gen 4? Either that or Toyota is using a greater buffer that offsets the gains.

    Either way, we'll find out in a few days whether the 22 miles remain or whether it changes (hopefully in the right direction)
     
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  9. giora

    giora Senior Member

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    ??!!
     
  10. giora

    giora Senior Member

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    Estimated EPA 120 MPGe or 28 kWh per 100 miles are based on energy from the wall (including charging losses) and not battery capacity.
    If we assume 15% losses the 22 miles gives 6.18*0.85=5.25 kWh 'real' capacity devoted to EV which is about 60% of total.
    With the PiP it was already established that the usable capacity devoted to EV is 2.7-2.75 kWh (from about 85% to about 23% SOC) which is 62% of total.

    My speculation - the estimated EPA EV range that will be announced at October 3 will be higher than 22 miles, probably 24-25 and the usable capacity for EV will be higher than 60% of total.
     
    #10 giora, Sep 28, 2016
    Last edited: Sep 28, 2016
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  11. john1701a

    john1701a Prius Guru

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    40 km was what I stated years ago as realistic for a high-volume profitable target. That's 25 miles... which looks likely.

    Whatever the number ends up, remember that we get both cabin & battery warming improvements. That will be great for those like me, who deal with months of endless winter each year.
     
  12. Lee Jay

    Lee Jay Senior Member

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    Speaking of that, I gathered from other other threads that it will stop drawing power from the grid when you power it up to pre-heat/cool. However, what if you let it warm for, say, 5-10 minutes and then shut it off for a similar time. Will it start charging again and recover some of the used energy or do you need to unplug/replug to get it to do that?
     
  13. john1701a

    john1701a Prius Guru

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    It should resume charging automatically.
     
  14. wjtracy

    wjtracy Senior Member

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    It could be important in California next legislative session when they go to extent the green sticker HOV program past 2019. Plug-in America is recommending equal treatment of PHEV and BEV as long as the PHEV gets at least 25 miles EV I believe...of course I am not expecting the legislators to adhere exactly to that. But I think 8kWhr batt is now the defacto plug-in target if you want to get incentives.
     
  15. Trollbait

    Trollbait It's a D&D thing

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    A range near 25 miles was what I was actually expecting of the next PiP.

    Since the pack is only air cooled by a fan, Toyota could be playing it safe in terms of the buffer on the battery. This also ensures the pack won't be an issue for the 10yr/150k mi CARB warranty.
     
  16. drash

    drash Senior Member

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    On the PiP, when I did a preconditioning for cooling during the summer, the L2 charger would continue to supply power while the A/C was turned on to cool the interior down. If the draw from the battery was more than the on-board charger would allow, the L2 EVSE continued to charge the battery after the preconditioning was finished. I don't believe the Prime will be any different, except since it has an on-board 3.3 kWh charger, it will keep up with the heating and/or A/C requirements.


    iPhone ?
     
  17. Lee Jay

    Lee Jay Senior Member

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    I was thinking about L1 (120V).
     
  18. drash

    drash Senior Member

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    Same thing happened before I got the L2 EVSE, except the L1 would come on and continue to charge for a lot longer to recharge the battery after the precooling was finished. All preconditioning is done through the battery. The EVSE just replaces, automatically, what is being used. The EVSE, both L1 and L2, comes on when I pressed the A/C button on my key fob.


    iPhone ?
     
  19. Lee Jay

    Lee Jay Senior Member

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    So, it continues to inject energy while the A/C is on, or restarts if charging had previously finished?
     
  20. drash

    drash Senior Member

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    Yes.


    iPhone ?
     
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