Charging at the top of a hill

Discussion in 'Prime Main Forum (2017-Current)' started by lllars, May 2, 2019.

  1. jb in NE

    jb in NE Senior Member

    Joined:
    Apr 13, 2018
    1,862
    1,253
    0
    Location:
    Nebraska
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Premium
    The OP said 3%.
     
  2. lextoy

    lextoy Active Member

    Joined:
    Apr 22, 2010
    280
    122
    0
    Location:
    philadelphia
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Premium
    i do my EV in miles. 3% seems like a very small hill...i can get 32 miles on a charge so 3% of that is only about 1 mile of EV regen.
    this hill cant be very long or steep. theres several around me, philly burbs that arent that long or steep but i can generate 2 miles of EV range, thus 6%. no place to burn off any charge before hitting this hill ? turn on ac and seat heater when you get in? be a little more aggressive with throttle and braking before the slope starts ? run in Power mode instead of eco mode, i can easily kill miles off the meter in Power mode if i want to , and its fun! i have free electric at work and home... and my commute is 25 miles round trip. plus hills to charge on.
    you have too much energy available, good problem to have. if you use hv for some uphills, can you go 2 days between charges? i do this now ,just to get ICE some exercise, first 3 or 4 months i'm trying to run ice extra to break it in, but will likely continue as i can charge every other day, getting closer to 50 miles between charging, just by hitting HV mode for a hill and small high way section on the commute...
     
  3. fuzzy1

    fuzzy1 Senior Member

    Joined:
    Feb 26, 2009
    12,302
    5,889
    90
    Location:
    Western Washington
    Vehicle:
    2012 Prius
    Model:
    Three
    I believe all Prii want to go through a substantial warm-up cycle once the engine starts spinning. This can be terminated by shutting off the ignition, but that requires parking the car. If it is rolling, then the warmup cycle continues.

    Even Gen3 non-plugins with the EV switch, once the ICE fires, you can't push EV to make it quit until it is warm enough. This Prime continuing to spin even after the bottom of the hill, is an extension of the same warmup requirement.
     
  4. thefranchise713

    thefranchise713 Junior Member

    Joined:
    Mar 11, 2019
    75
    52
    0
    Location:
    Buffalo, NY
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Advanced
    That's a bummer, but great info (and thanks for sharing.)
     
  5. jb in NE

    jb in NE Senior Member

    Joined:
    Apr 13, 2018
    1,862
    1,253
    0
    Location:
    Nebraska
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Premium
    All of those things will work but they defeat the purpose of maximizing energy recovery. If the battery is not fully charged at start, then the entire amount of regeneration can be captured in the battery without having to "burn off" some battery to make space. The energy "burned off" is coming from the wall outlet.
     
  6. lllars

    lllars Junior Member

    Joined:
    Mar 26, 2019
    32
    14
    0
    Location:
    Southern Vermont
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Plus
    Ok, the first experimental data is in. Last night the battery was at 61%, this morning it was 100%, but it still gave me a warning that the charger had disconnected before charging could complete. Also, it dropped to 99% while I was sitting in the driveway, so I think it was on the low end of 100% (like 99.5%). It made it all the way all the way down the hill without the engine turning on. I did have the heat turned on, so that would have helped. The battery was down to 55% at the end of the drive. Ambient temp was 45F.

    I also captured data from the drive with the HybridAssistant app. That shows a starting state of charge (SOC) of 81.18% and a ending SOC of 51.37%. SOC maxed out at 82.8% at the bottom of the hill. You can see from the graphs that there were a couple times in the drive where the engine almost kicked on because the battery couldn't soak up charge fast enough: the first time at the bottom of the hill, and the second time where I had to slow down suddenly for some construction workers. The drive is in two parts, so two graphs, one mostly downhill and the other the mostly uphill return trip.

    More data coming this afternoon, as I've got another 1.75hr charge scheduled to finish at 1pm.

    IMG_0977.jpg IMG_0978.jpg
     
    jb in NE likes this.
  7. lllars

    lllars Junior Member

    Joined:
    Mar 26, 2019
    32
    14
    0
    Location:
    Southern Vermont
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Plus
    This is a cool idea. I might be able to set up a single raspi within the house but close enough to the car to get a bluetooth connection. I could also have it turn off the the charger through it's web interface, with no extra hardware needed. I don't think the OBD adapter works when the car is powered off though, so that'd be a killer (I'll go check).

    It's about 3/4 mile long, dirt road, moderately steep. I typically drive it at 20 to 25 mph, much faster and I might end up in a ditch. There's really no where to burn off charge by goosing it. I typically regen 3 to 4% of the battery going down and consume 8 to 10% of the battery on the way up.
     
  8. sam spade 2

    sam spade 2 Senior Member

    Joined:
    Mar 31, 2018
    1,838
    863
    0
    Location:
    USA
    Vehicle:
    2017 Prius c
    Model:
    Four
    I don't understand this part of the discussion.
    Energy is energy.
    Why would you think that it is in ANY WAY a good thing to deplete part of the stored charge........just so you can immediately fill it up again ??
    Full is full.
     
  9. noonm

    noonm Member

    Joined:
    Feb 5, 2019
    252
    205
    0
    Location:
    NJ
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Plus
    Ah, good point, I think you are right. It may require some more intrusive modifications of the car to get the charge level when off.
     
  10. lllars

    lllars Junior Member

    Joined:
    Mar 26, 2019
    32
    14
    0
    Location:
    Southern Vermont
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Plus
    Well, it appears I was at least partially wrong. I can connect to the OBD adapter with the car off. I'm not sure how to get the battery % or state of charge though. HybridAssistant connects to the adapter but says "waiting for car" and shows very little data. I can also connect with the OBDLink app, but that doesn't show any battery data either. It's possible that OBD adapter simply can't access the data with the car off. Anyone know a PID code for battery charge info?

    Screen_2019-05-03_10-37-25.png Screen_2019-05-03_10-39-57.png
     
  11. lllars

    lllars Junior Member

    Joined:
    Mar 26, 2019
    32
    14
    0
    Location:
    Southern Vermont
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Plus
    Right, it wouldn't be an ideal solution to intentionally burn off charge. However, if you're about to go down a hill then the car has a bunch of gravitational potential energy that has to be converted to something. Ideally it would be converted to battery charge, but if the battery is already full then you've got to pick a less ideal option. 1. Go down in neutral and convert the energy to heat in the brakes. 2. Let the engine turn on and use that as a brake. 3. Convert it all to kinetic energy (minus air drag) and try to stay on the road at 100mph. 4. Hit a tree 5. Intentionally bleed off some energy in advance. 6. ...
     
    kevin.c likes this.
  12. jb in NE

    jb in NE Senior Member

    Joined:
    Apr 13, 2018
    1,862
    1,253
    0
    Location:
    Nebraska
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Premium
    Last option - move to house at bottom of hill.
     
    #32 jb in NE, May 3, 2019
    Last edited: May 3, 2019
    bruceha_2000 likes this.
  13. noonm

    noonm Member

    Joined:
    Feb 5, 2019
    252
    205
    0
    Location:
    NJ
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Plus
    I believe the OBD2 port only reports data when the car is on, even if you can connect to the device. However, I'll check it with my OBD2 connector (I also have a copy of torques) to see if there is any way to get info when the car is off.
     
  14. jb in NE

    jb in NE Senior Member

    Joined:
    Apr 13, 2018
    1,862
    1,253
    0
    Location:
    Nebraska
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Premium
    My experience - the car has to be powered up to provide data to the OBD2. I've always had to have the car ON (not accessory) to read OBD2 data.
     
  15. fuzzy1

    fuzzy1 Senior Member

    Joined:
    Feb 26, 2009
    12,302
    5,889
    90
    Location:
    Western Washington
    Vehicle:
    2012 Prius
    Model:
    Three
    I thought the point was to avoid trigger the ICE into engine braking, which then forces it into its full gasoline-burning warmup cycle, which then burns more fossil-fuel energy for this cycle than the other energy he was looking to scrub to avoid this.

    And then his gasoline tank is no long full.
     
  16. lllars

    lllars Junior Member

    Joined:
    Mar 26, 2019
    32
    14
    0
    Location:
    Southern Vermont
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Plus
    Second charge is complete, but I haven't driven it yet. It charged up to 90% (from 55). SOC is 76%. Charger recorded 2.40 kWh of energy use.

    So, 35% charge this time, 39% last time. That's maybe more variability then I was expecting, but not too bad. I don't have the pre-charge SOC or kWh used for the first charge, so I don't know if there is similar variability there yet. I'll try to keep a closer eye on those in the future.
     
  17. lllars

    lllars Junior Member

    Joined:
    Mar 26, 2019
    32
    14
    0
    Location:
    Southern Vermont
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Plus
    Correct!
     
  18. bruceha_2000

    bruceha_2000 Senior Member

    Joined:
    Jan 2, 2004
    3,050
    291
    19
    Location:
    Northwest VT
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Advanced
    Given the high voltage battery is disconnected until the car goes to Ig On, it seems unlikely anything would be available with the car off.
     
  19. lllars

    lllars Junior Member

    Joined:
    Mar 26, 2019
    32
    14
    0
    Location:
    Southern Vermont
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Plus
    ooo... just thought of another workaround (#6): The L2 charger's web interface reports the current charge rate in amps. The car automatically reduces the charge rate as the battery fills up. I could write a script to monitor the charge rate and turn off the charger when it reaches some low value (like 3 amps).
     
  20. noonm

    noonm Member

    Joined:
    Feb 5, 2019
    252
    205
    0
    Location:
    NJ
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Plus
    But the car has to be keeping track of the SOC somehow so it knows when to start charging for scheduled departures, right? I just don't know if it's possible to access that info through any normal means.
     
Loading...