Prime electric bill cost to operate

Discussion in 'Prime Plug-in Charging' started by PriusPrimeOwner, Jan 17, 2017.

  1. Db17

    Db17 Member

    Joined:
    Jan 9, 2017
    130
    57
    0
    Location:
    Ventura county
    Vehicle:
    2017 Prius Prime
    Model:
    Plug-in Advanced
    That's probable/possible. But it still takes 6.3 kWh though you might save a few pennies. But the wait will definitely be shorter.
     
  2. EV-ish

    EV-ish Active Member

    Joined:
    Nov 17, 2016
    602
    277
    0
    Location:
    SW US
    Vehicle:
    2017 Prius Prime
    A kWh is NOT an amount of power. It is an amount of energy
     
  3. EV-ish

    EV-ish Active Member

    Joined:
    Nov 17, 2016
    602
    277
    0
    Location:
    SW US
    Vehicle:
    2017 Prius Prime
    L2 has less losses. It is somewhat non-intuitive because L1 usually runs at lower amps than L2 and therefore has less resistive losses, but most of the charging loss is fixed to time for the EVSE electronics, so the faster charging time ends up being the major savings.
     
    MMBH, MikeDee and bisco like this.
  4. Lee Jay

    Lee Jay Senior Member

    Joined:
    Jun 25, 2009
    4,993
    3,623
    0
    Location:
    Westminster, Colorado
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    I'm a bit confused about this.

    Switching loss in the battery charger should be proportion to voltage squared (because you're shorting out the MOSFET parasitic capacitance in each switching cycle and the energy in that capacitance is 1/2*C*V^2. Four times as much at 240V versus 120V but only 2.66 times the power (more amps too) - lose.
    Forward conduction loss should be proportional to current squared. 1.77 times as much at 240V but 2.66 times the power - win.
    Battery charging losses should be proportional to battery current squared. 2.66 times the battery current means more than 7 times the battery losses (which are quite low).

    I'm surprised that the forward conduction losses so drastically dominate the other sources that 240V charging would be not only more efficient, but by the reported 15%. Switching losses and conduction losses are usually comparable so I'd expect this to be close to a wash.

    Weird.
     
  5. EV-ish

    EV-ish Active Member

    Joined:
    Nov 17, 2016
    602
    277
    0
    Location:
    SW US
    Vehicle:
    2017 Prius Prime
    You are thinking over my head, but I don't think the difference is an absolute 15%
    L2 is around 12-14% losses
    L1 is around 18% losses

    Or so I have read.
     
  6. Db17

    Db17 Member

    Joined:
    Jan 9, 2017
    130
    57
    0
    Location:
    Ventura county
    Vehicle:
    2017 Prius Prime
    Model:
    Plug-in Advanced
    Technically you are correct. Please excuse my poor semantics ;)
     
  7. I'mJp

    I'mJp Senior Member

    Joined:
    Mar 12, 2012
    627
    540
    0
    Location:
    Ma, USA
    Vehicle:
    Other Electric Vehicle
    Model:
    Three
    Is the heat generated by the losses in the charger in the cabin area or on the outside ?
    Is it helping to warm the car ?
     
  8. Lee Jay

    Lee Jay Senior Member

    Joined:
    Jun 25, 2009
    4,993
    3,623
    0
    Location:
    Westminster, Colorado
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    The charger is under the rear seat.
     
  9. I'mJp

    I'mJp Senior Member

    Joined:
    Mar 12, 2012
    627
    540
    0
    Location:
    Ma, USA
    Vehicle:
    Other Electric Vehicle
    Model:
    Three
    It must have forced ventilation that leads to somewhere, cain't just let heat build up under a seat.
     
  10. Db17

    Db17 Member

    Joined:
    Jan 9, 2017
    130
    57
    0
    Location:
    Ventura county
    Vehicle:
    2017 Prius Prime
    Model:
    Plug-in Advanced
    IMG_0473.PNG
    So if you charge your Prime once every day, that amounts to what, the somewhat less than the cost of a Happy Meal over a month?

    I just bought a device to track my home energy usage, but by my calculations using one full charge a day instead of buying gas will net me about a $12/ month savings. So the delta between 14% or 18% loss doesn't change my world.

    So I'm pretty new to this forum. So far I haven't found and credible independent measurements of about anything posted. I've never found manufacturer's marketing numbers (or EPA's) to match what most of us in the real world come up with. My point here is that we are mostly speculating. Here's my first night's car charge.
     
  11. Lee Jay

    Lee Jay Senior Member

    Joined:
    Jun 25, 2009
    4,993
    3,623
    0
    Location:
    Westminster, Colorado
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    I suspect it can. It can probably tolerate being at over 100C. It has to be able to survive the car sitting in the sun in the summer while charging. It might have a heat sink that's bonded to the car body or something.

    Looks like it might have a small fan that blows air forward into the passenger compartment. upload_2017-1-22_10-2-24.png
     
  12. giora

    giora Senior Member

    Joined:
    Aug 28, 2010
    1,966
    719
    0
    Location:
    Herzliya, Israel. Car: Euro version GLI
    Vehicle:
    2013 Prius Plug-in
    Model:
    N/A
    Cancelled.
     
    #112 giora, Jan 22, 2017
    Last edited: Jan 22, 2017
  13. giora

    giora Senior Member

    Joined:
    Aug 28, 2010
    1,966
    719
    0
    Location:
    Herzliya, Israel. Car: Euro version GLI
    Vehicle:
    2013 Prius Plug-in
    Model:
    N/A
    This looks like a recording power meter (Wattmeter), can it sum up and show you the total energy consumed? because that what you are after (I think).
     
  14. giora

    giora Senior Member

    Joined:
    Aug 28, 2010
    1,966
    719
    0
    Location:
    Herzliya, Israel. Car: Euro version GLI
    Vehicle:
    2013 Prius Plug-in
    Model:
    N/A
    We are talking here of battery usable capacity (for EV) and the amount of charge consumed from the wall (=~payable charge) to charge it up, these have nothing to do with driving habits etc. So, EPA calculated data of amount of charge from the wall is applicable to everybody in the real world (at least when the battery is new).
    And, as I posted earlier, this ~6.3 kWh consumed from the wall (=~payable energy) was already confirmed here by some owners' measurements. So, what exactly do you mean by "credible independent measurement"?
     
    #114 giora, Jan 22, 2017
    Last edited: Jan 22, 2017
    EV-ish likes this.
  15. Db17

    Db17 Member

    Joined:
    Jan 9, 2017
    130
    57
    0
    Location:
    Ventura county
    Vehicle:
    2017 Prius Prime
    Model:
    Plug-in Advanced
    Yes it is. But it is monitoring my entire service and is not dedicated to car charging.
     
  16. EV-ish

    EV-ish Active Member

    Joined:
    Nov 17, 2016
    602
    277
    0
    Location:
    SW US
    Vehicle:
    2017 Prius Prime
    1. Start with EPA 133 MPGe and 25 miles range. The rest follows
     
  17. EV-ish

    EV-ish Active Member

    Joined:
    Nov 17, 2016
    602
    277
    0
    Location:
    SW US
    Vehicle:
    2017 Prius Prime
    In the same way that 2+2 is technically 4.
     
  18. Db17

    Db17 Member

    Joined:
    Jan 9, 2017
    130
    57
    0
    Location:
    Ventura county
    Vehicle:
    2017 Prius Prime
    Model:
    Plug-in Advanced
    Did you have to look that up?;)
     
  19. I'mJp

    I'mJp Senior Member

    Joined:
    Mar 12, 2012
    627
    540
    0
    Location:
    Ma, USA
    Vehicle:
    Other Electric Vehicle
    Model:
    Three
    It is force ventilated.

    The input is directly under the back console.
    I usually keep a small trash buck on the floor nearby, and the fan sucked the plastic liner to the vent, causing the fan to go into really high gear.

    There is another vent to the passenger side on the floor, but it does not seem to be forced. I did the tissue test to see if there was pressure or suction, and I could not detect either.

    I was charging 240 volts, 16 amps, and the foot well on the passenger side was at about 56 degrees F.
    Ambient for the car was 45, for the garage 38.
    Free heat for the winter!
     
    giora likes this.
  20. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    88,814
    39,713
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    maybe the fan was off.
     
Loading...