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Battery recharge cycle sucks...

Discussion in 'Gen 3 Prius Fuel Economy' started by Threej, Nov 13, 2018.

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  1. Threej

    Threej Member

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    So something I've noticed on my 2010--
    Basically, there's 3 ways my battery gets recharged:
    1. Long breaking (works great).
    2. Driving highway speeds (works great)
    3. Engine recharge when battery drops to 2 bars (uh... not so great).

    What I mean is, I'll be at 60mpg, and the engine will burn me down to 50 mpg (having driven 20 miles) all to gain me a total of one pip of battery life. That seems ridiculous. If I just gunned it up to 60 MPH and braked back down, I'd refill my battery using half the gas. Why on earth isn't the low-battery recharge more efficient?

    This is presuming I'm stopped, such as in traffic, when the recharge starts, hence why I can't just accelerate my problems away.
     
    #1 Threej, Nov 13, 2018
  2. bisco

    bisco cookie crumbler

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    you're oversimplifying. prius is designed to reduce emissions.
    mpg's are just a happy byproduct
     
    #2 bisco, Nov 13, 2018
  3. Maarten28

    Maarten28 Active Member

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    Do you have any scientific evidence to back that up? My guess is you won't get 60 mpg either if you gun it to 60 mph and then brake.
    Because the Prius only uses what's left of the marginal inefficiency to recharge the HV battery. It will not run extra high revs to charge the HV battery (except when you're at 2 bars, 40% SOC).
     
    #3 Maarten28, Nov 14, 2018
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  4. Threej

    Threej Member

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    I have the HSI display broadcasting numbers to me. Yeah yeah, not entirely accurate. But the comparative drop is still pretty crazy.

    You mean the exact situation I was explicitly asking about?
     
    #4 Threej, Nov 14, 2018
  5. Threej

    Threej Member

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    I'm not that familiar with emissions systems, are there legitimate situations where burning more gas produces fewer emissions?
     
    #5 Threej, Nov 14, 2018
  6. bisco

    bisco cookie crumbler

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    a simple one is the warm up cycle. less emissions are produced than running a cold engine when necessary
     
    #6 bisco, Nov 14, 2018
  7. Grit

    Grit Senior Member

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    Easy fix- buy an all electric vehicle. It does what you want.
     
    #7 Grit, Nov 14, 2018
  8. Maarten28

    Maarten28 Active Member

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    So, what's the complaint? That burning fuel to recharge the battery is inefficient? Yes it is. That's also why it is less efficient to force EV-mode and run the battery down than to let the car do its thing.
     
    #8 Maarten28, Nov 21, 2018
  9. fuzzy1

    fuzzy1 Senior Member

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    Yes. For one, in older simpler engines, a lean mixture is a bit more fuel efficient but produces excessive NOx.
     
    #9 fuzzy1, Nov 21, 2018
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  10. sam spade 2

    sam spade 2 Senior Member

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    Because of the system design, the HV battery MUST be kept above a certain minimum level of charge.
    Partly because it does other stuff besides turning the engine, like run the A/C compressor as an example.

    If it did not do what you are complaining about, it would be pretty easy to make it go below the minimum threshold and that would be kind of like running out of gas. Dead in the water.
     
    #10 sam spade 2, Nov 21, 2018
  11. Threej

    Threej Member

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    I think you misread my post. I have no problem with the battery charging. I have a problem with one of the three methods of battery recharging being inefficient compared to the other two, when it seems (given that it's the only one where no other load is required) it would be the most efficient.
     
    #11 Threej, Nov 21, 2018
    Last edited: Nov 21, 2018
  12. Threej

    Threej Member

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    No. The complaint is that if I gun the prius from a start up to 60 mph, and then brake to fill up my battery, I burn less gas than if I sit parked and let the engine devote all its energy into filling the battery. Both methods recharge my battery. One of them also moves my car 2 miles and uses less gas doing it.

    That seems stupid.
     
    #12 Threej, Nov 21, 2018
  13. fuzzy1

    fuzzy1 Senior Member

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    (1) How did you measure this?
    (2) What were the final engine temperatures of these two methods? Did they achieve similar degrees of warmup?
     
    #13 fuzzy1, Nov 21, 2018
  14. sam spade 2

    sam spade 2 Senior Member

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    I didn't mis-read your post.
    I maybe misunderstand it......because what you are trying to say makes no sense whatsoever.
    Your "logic" is severely flawed.
    Your best course of action is: JUST DON'T WORRY ABOUT IT.
     
    #14 sam spade 2, Nov 21, 2018
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  15. jack black

    jack black Active Member

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    exactly, the best way to drive (non-plug in) hybrid is to avoid depleting battery to prevent that inefficient fuel burn. win-win situation: best MPG and little wear and tear on battery.
     
    #15 jack black, Nov 22, 2018
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  16. Maarten28

    Maarten28 Active Member

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    I don't know why that seems stupid. If I have an ordinary car and sit at the curb with my engine running, it is also less efficient. I'm burning fuel without going somewhere.
    There is also an efficiency point for the ICE. That is not at 1300 rpm where it sits at high idle.
    And I'd also like to see more support for your claim than just "it is so". The Hybrid assistant app has a fuel quantity measurement. I have no idea how accurate it is, but could you use that to see if that supports your claim?
     
    #16 Maarten28, Nov 22, 2018
  17. sam spade 2

    sam spade 2 Senior Member

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    For one thing, the OP doesn't seem to understand what Miles Per Gallon means.
    Any time, with any vehicle, that you are burning gallons without going any miles.......your MPG goes down.
     
    #17 sam spade 2, Nov 22, 2018
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  18. Threej

    Threej Member

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    Isn't that part of my question? If its low-battery recharge cycle happens at 1300 rpm and that's ineffecient... why doesn't it run it at 2500 rpm? The car's warmup cycle already demonstrates the prius has no problem running the engine when you're not moving.
     
    #18 Threej, Nov 23, 2018
  19. bisco

    bisco cookie crumbler

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    probably one of the reasons why newer hybrids are more efficient
     
    #19 bisco, Nov 23, 2018
  20. bisco

    bisco cookie crumbler

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    prius does not charge the battery above two purple bars when you are sitting, so they must know it isn't efficient to charge higher when not moving.

    but it is necessary to keep the battery above a predetermined level for longevity
     
    #20 bisco, Nov 23, 2018
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