Charging at the top of a hill

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

  1. bruceha_2000

    bruceha_2000 Senior Member

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    Hmmm, true. I have to start thinking Prime vs Gen II.
    Clearly the charging function needs to be able to monitor the battery with the car fully shut down (from the driver's perspective).
     
  2. Landon51

    Landon51 Member

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    I didn't even consider that you wouldn't have Torque or something else running.

    Posted via the PriusChat mobile app.
     
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  3. sam spade 2

    sam spade 2 Senior Member

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    And this is NOT a reasonable option because it accomplishes pretty much NOTHING useful.
    Unless maybe you just enjoy a pointless "game".
    It seems like a LOT of hybrid owners do.
     
  4. fuzzy1

    fuzzy1 Senior Member

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    You are still missing his primary point, which he verified back at post #37: how to prevent the ICE from initiating a fossil-fuel-wasting engine warm-up cycle.
     
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  5. lextoy

    lextoy Active Member

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    yup . its pretty much the worst thing you can do to an ICE . short tripping.
    running ICE for 5 minutes, for any reason, like this "warm up cycle" isnt enough time to properly warm up an engine and warm up the fluids/oil. having it come on while you are coasting downhill is actually what is pointless, and even damaging long term.
    finding a way to STOP the ICE from coming on in this scenario is a reasonable pursuit.
    but now that i know the OP is rolling down a dirt road for 3/4 mile every day... i would just move;)
    who takes a Prime on a dirt road !!!
     
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  6. sam spade 2

    sam spade 2 Senior Member

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    Well, it appears that the people who designed and built the vehicle don't agree with that.

    How about comparing that potential long term "damage" to whatever stress would happen if you slammed the accelerator down and forced the ICE to go from stone cold to full power ??

    I don't know which would be worse......but my money is on the Toyota engineers.
     
  7. lllars

    lllars Junior Member

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    The day we bought it was the second day of mud season. I left 3-4" deep ruts most of the way up the hill, and was glad to have not gotten stuck. Oh well, so much for keeping it clean ;-)

    Actually our road is generally quite good, well maintained in winter, and typically only gets soft for a few days in spring. Snow tires are a must though. Of course AWD would be useful up here, but at twice the cost and half the mpgs, no thanks. Also, our other car is a 4wd Tundra.
     
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  8. bisco

    bisco cookie crumbler

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    ah, mud season. my daughter used to drive the bookmobile in st albans
     
  9. lllars

    lllars Junior Member

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    Ok, I seem to have this problem mostly solved. I've written a script that monitors the L2 charger's website. It tracks the amount of amps going to the car and stops the charge as soon as the current drops below 10A. It needs a bit more testing, and then I just need to deploy it onto a raspberry pi so it is always running.

    I monitored one charge so far, and was surprised to see that the charge current does not taper off at all until the very end of the charge. What I saw is that it charged at 14.6A continuously and only started tapering once the battery was 95% or so full. Actually, I'm also seeing the occasional blip, where it drops to 0.5A for a minute or so; maybe the car does this periodically to measure how full the battery is? Graph of charge current vs time:

    c1.png
     
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  10. lllars

    lllars Junior Member

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    Here are graphs from two more charges. Interesting that they all have those 2 dips in current towards the beginning.

    Note that these have all been "charge now" charges. I wonder if the current profile would be different at all for a scheduled charge. Maybe the car would charge a bit more gently if not in a rush?

    c2.png c3.png
     
  11. will the engineer

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    Hey I am actually facing the same issue. But haven't had the engine kick back in.

    Not sure what this will do to the Prius in the long run
     
  12. lllars

    lllars Junior Member

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    So, you charge up to 100%, then go down a hill without the engine coming on? How big is your hill?
     
  13. john1701a

    john1701a Prius Guru

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    Scanned through the entire thread. Looks like no once is aware of the easiest solution.

    JUST GET A L2 CHARGER THAT ALLOWS YOU TO SPECIFY CAPACITY TO REPLENISH.

    That interface for my JuiceBox Pro provides the means of partial recharge. You just move a slider to tell it where to stop.
    Screenshot_20190508-085138_EV%20JuiceNet.jpg

    I suspect it's not a perfect solution, but it sure seems a worthy option to try.
     
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  14. john1701a

    john1701a Prius Guru

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    See what happened when I moved that slider....

    Screenshot_20190508-085734_EV%20JuiceNet.jpg
     
  15. maddog2020

    maddog2020 Junior Member

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    Seems that the only reasonable solution is to move to the bottom of the hill. That way you won’t have to waste any of all that charged energy.

    :)


    iPhone ?
     
  16. will the engineer

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    I will get the distance and maybe I can figure out the slope with an app.

    I will get back to you.

    All I know is going 50 mph up take about 10 to 15% of battery (depending on outside temp)
     
  17. will the engineer

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    So far these are the solutions we have? hmmmm...

    Maybe I should call my toyota dealership and ask. But I have no doubt they'll say don't worry about it
     
  18. lllars

    lllars Junior Member

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    Sounds pretty big. How much charge can you get from it going down? And if you are fully charged before starting down, does your car stay at 100% for a long time afterwards (i.e. is it charging to over 100%).

    Slope could also be a factor. It seems like the car limits how rapidly it will charge the battery as the battery gets full. A steep slope might exceed that limit quickly whereas a gentle but long slope might stay under the limit.
     
  19. lllars

    lllars Junior Member

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    This is cool. Have you tested that it actually works? My charger (flo brand) doesn’t seem to have any idea how charged (%) my car is. It only reports how much energy (kWh) has been put into it. On the other hand, it was free, so I suppose I can’t complain about it too much.
     
  20. will the engineer

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    slope is an absolute factor!

    The weight of the car shift back making it more difficult to go up. Being that electricity is less dense than fuel. No wonder my battery drains so quickly. every 5 seconds I lose 1% (off the top of my head)

    From the top of the hill (litterally) then going all the way down I get up to 3% battery
     
    #60 will the engineer, May 8, 2019
    Last edited: May 8, 2019
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