CHG mode to increase overall range

Discussion in 'Prime Main Forum (2017-Current)' started by Dave7, Jun 17, 2020.

  1. Dave7

    Dave7 Junior Member

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    (Reposted as a new thread).To me the big advantage of CHG mode is to increase overall range. Right before stopping to fill the gas tank run the CHG mode, then with the added EV miles you have almost maximum range. Almost full battery and full tank. Good for long trips.I don't know how much fuel it takes in CHG mode to charge the battery so if you are running real low on gas this might not be the best idea.
     
  2. m8547

    m8547 Active Member

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    It would be an interesting experiment to see how much fuel is used for a given amount of charging. Has anyone tested it?
     
  3. smyles

    smyles Active Member

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    Gas-only range is 500+ miles.
    30 miles of EV don't make that much difference.
     
  4. rdgrimes

    rdgrimes Senior Member

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    Looking at a Gal/hr calculation the amount used will be determined by the battery SOC at the time. The more drained the battery is, the more load on the ICE. On the highway it might not make a big difference when the ICE is running anyway. In town the ICE can be pretty well loaded if the battery is drained. (compared to normal ICE fuel use). You can do your own calculation just by calculating the fuel used by the total miles driven while charging then running EV till drained again. I'd be pretty surprised if you came out ahead.
     
  5. Salamander_King

    Salamander_King Senior Member

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    You are charging the battery using gasoline. Yes, the range would be longer by the amount of 80% charge at the time you fill-up the tank on a road, but you reduced the range on the tank before the fill-up. My feeling is that the reduction in miles you might have been able to drive before filling up is greater than the EV range from the 80% charged traction battery using CHG mode. That is, the overall range would be shorter if you use CHG mode than not use it.
     
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  6. GSK

    GSK Member

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    to me it's worth it just to be able drive more in EV mode.
     
  7. eatriceyo

    eatriceyo New Member

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    why waste gasoline when you can charge for free at certain charging stations.
     
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  8. m8547

    m8547 Active Member

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    Can't charge for free while driving. My time isn't free, and it's rarely worth it to wait at a charging station.
     
  9. bisco

    bisco cookie crumbler

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    if you get 20 miles of ev, will you lose any hv?
     
  10. Wolfie52

    Wolfie52 Senior "Jr" Member

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    I see people doing this all the time. Usually they drive Leafs.
     
  11. Dave7

    Dave7 Junior Member

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    no, you run in charge mode until you get to the gas station, then you fill it up and have a full tank and battery
     
  12. Salamander_King

    Salamander_King Senior Member

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    But you lost HV range on the tank before by lowering mpg with CHG mode. Thus the overall range is shorter.
     
  13. Dave7

    Dave7 Junior Member

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    ok, I see what you mean, guess we would need to find a gas station on the bottom of a hill.
     
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  14. Schrauger

    Schrauger Junior Member

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    You might get more range in the sense that you can run the gas tank empty. Either when charging or afterwards, if you keep it on gas mode until the tank is dry, then use the tiny bit of electric to get to a gas station. That will get you the maximum range possible, rather than filling up the tank when you still have a gallon or so left.

    With a fully charged ev battery, you lose range anxiety on the gas side. Once you use up the last drop of gas and start going to electric, you know how many miles you have to find a gas station before you're dead in the water. Assuming you're not out in the boonies, 20-25 miles is plenty to find a station to fill up the tank from empty to full.

    But if you don't run it dry, then I don't see how it would help you. You'd have a longer second leg, but your first leg would be reduced because of the gas used to charge the battery. Combined with the conversion loss, I don't think your overall trip average would have fewer stops for fillups.
     
  15. MikeDee

    MikeDee Senior Member

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    I remember something about running a tank dry is bad for the Prius.
     
  16. Trollbait

    Trollbait It's a D&D thing

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    Running the tank dry in any car risks damaging the fuel pump from overheating.

    In regards to non-plug hybrids, people have continued driving with an empty tank, which overdraws the battery, damaging it.
     
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  17. Blair McCall

    Blair McCall New Member

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    It depends on a lot of factors. You will operate less efficiently in charge mode. As power from the motor is transferred to the battery there will be losses.

    The most efficient method to charge is obviously by plugging it in - assuming electric rates are reasonable. There are some cases where charging electrically will cost more than the increase in gas.

    I am a new Prime owner and I am still working on figuring out what works best for me. So far, running charge mode on the highway to top off my battery and using EV mode on the surface streets has yielded the best results.
     
  18. Mikhail Bond

    Mikhail Bond Junior Member

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    I only get 430
     
  19. Salamander_King

    Salamander_King Senior Member

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    Do you drive fast? Or do you do a lot of short trips on HV? DTE is roughly the reflection of the mpg on your last tank. Gas empty light comes on after using ~9.3gal from a full tank. It changes quite bit if your driving condition changes. In my case summer best DTE is upper 500s miles, but in wither it drops to upper 400s miles. For 430miles DTE, your last tank mpg was 430/9.3=46mpg which is bit low, but not unreasonable. My mpg drops to 40s in winter, but goes up to near 60 in summer.

    See this thread: What is your DTE after fill-up? | Page 2 | PriusChat
     
    #19 Salamander_King, Jul 2, 2020
    Last edited: Jul 2, 2020
  20. jerrymildred

    jerrymildred Senior Member

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    The advertised range of the tank is calculated by multiplying the EPA estimated mpg by the amount of fuel in the tank. Going that far (assuming the EPA mpg) would mean running it till it's completely out of gas. So, the advertisements for 540 miles total range are very unrealistic unless you're getting well over EPA mpg and willing to drive with the gauge on empty for a long time. Not the way most drivers operate.
     
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