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

Strange EV ratio accounting

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by 3PriusMike, Jul 9, 2013.

  1. 3PriusMike

    3PriusMike Prius owner since 2000, Tesla M3 2018

    Joined:
    Jun 21, 2009
    2,938
    2,288
    0
    Location:
    Silicon Valley
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    In another thread I discussed my attempt to see how far I could go in EV mode on a long downhill road. Can you drive 100+ miles in EV (no charging)? | PriusChat

    I also encountered some negative kw-hours. Let me explain.
    I left home with a full charge (14 miles) and used EV for 3-4 miles, got on the freeway and went ~100 miles and stopped for gas and reset my trip A and EV ratio #1. So I had a full tank of gas and about 10-12 miles of EV. I then used a few EV miles driving through various towns on the way to Tioga Pass. At one point I had about 5 EV miles left, 10 miles in EV and 1 kwh used (based on the EV ratio #1 display. I used up almost all EV miles as I approached the peak of Tioga Pass and headed down to Lee Vining...a 3000' drop...and I regen'ed to about 10 EV miles.

    I went to Mammoth Lakes and used up much of the EV miles driving around the city, going on hikes, dinner, etc. Uphill in HV to go on a hike, then 5 EV miles regen back to town. When I looked at the EV ratio #1 screen the next day I had ~25 EV miles, but 0 (zero) kwh used. All other numbers were correct in terms of EV and HV miles adding up to trip A miles, etc.

    It appears that the car knew I'd used a lot of downhill regen and reset the kwh to zero. Or something else? Later that day I did the (almost) 100 mile of EV (in other thread). Technically some of it was in HV doing regen downhill...but at the end of the day I had 100+ miles in EV and ~300 in HV, but zero kwh. (Other ~100 miles before I got gas)

    (I keep ~weekly logs of EV usage stats and the kwh always increment up in my normal daily commuting...but have never down a lot of downhill regen before except when the car was new and I wasn't keeping track)

    A bit strange.

    Mike
     
    #1 3PriusMike, Jul 9, 2013
    Tracksyde likes this.
  2. Tracksyde

    Tracksyde Member

    Joined:
    Sep 21, 2011
    1,429
    761
    0
    Location:
    So Cal
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    So basically, regen counts against kWh consumed?

    Interesting.. I guess it makes sense.. if the car knows how much it regenerated, no reason why it wouldnt/shouldnt deduct the "free electricity" if you're looking at the kWh from a "Consumption" standpoint.

    Any gasoline used to "generate" the "free electricity" (going up the hill) would be counted as consumption on the HV side. Counting the "free electricity" (regenerated and used in EV) as kWh consumed would be double-counting and decreasing the car's efficiency artificially.
     
    #2 Tracksyde, Jul 10, 2013
  3. mmmodem

    mmmodem Senior Taste Tester

    Joined:
    Nov 17, 2011
    2,732
    1,703
    0
    Location:
    Bay Area, CA
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    From my observations, I regenerated and used about 20 EV miles on a long trip with no opportunity to charge. This was shown on the EV ratio. However, kWh remain unchanged since the last time I plugged it in. My conclusion is that kWh shows intake and not consumption.
     
    #3 mmmodem, Jul 10, 2013
  4. 3PriusMike

    3PriusMike Prius owner since 2000, Tesla M3 2018

    Joined:
    Jun 21, 2009
    2,938
    2,288
    0
    Location:
    Silicon Valley
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base

    Yes.
    That is what I would have thought...and have observed on mild regen compared to wall charging.

    What was different this time was that the wall charging incremented my kwh as it was used, but later it was subtracted out after, maybe 3-5 kwh of regen miles were consumed.

    Mike
     
    #4 3PriusMike, Jul 10, 2013
(You must log in or sign up to post here.)