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Idle battery charge to full??

Discussion in 'Gen 4 Prius Fuel Economy' started by Kitats, Mar 1, 2021.

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  1. Kitats

    Kitats New Member

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    I was wondering if there was a Hack to Get the electric motor to charge the battery higher when idle in park.

    haven't tried it yet but possibly sitting in neutral instead of park might trick the computer? Or does pwr vs eco mode affect it?

    I feel like it puts more strain on the electric motor constantly turning on and off as opposed to running continuously for longer periods. But I could be wrong. thanks
     
  2. CooCooCaChoo

    CooCooCaChoo Active Member

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    Don't sit in neutral. It will not charge the hybrid battery pack.

    Just drive the car and let the computers take care of the charging. The car works well the way it was designed.
     
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  3. davecook89t

    davecook89t Senior Member

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    I guess you are talking about the Internal Combustion Engine charging the battery through Motor Generator 1. (It's the ICE supplying the power to charge the battery not MG1.) That used to be possible in the earlier Prius generations by simultaneously pressing the accelerator and brake in Drive (a process called "force charging"), but I believe that possibility was eliminated for the Gen 4 cars as Toyota's response to complaints about unintended acceleration (where it was believed that most instances of unintended acceleration were due to operator error, pressing the accelerator instead of the brake, to lessen the likelihood of that happening, Toyota simply disabled the signal from the accelerator pedal to the throttle if the brake was pressed at the same time). So it is no longer possible to force charge the battery, that's just as well, the Battery ECU manages the charge better than any human could anyway.

    It's not advisable to leave the car in Neutral for more than brief periods of time. The ICE cannot charge the battery in Neutral, no matter how high the RPM. Leaving the car in Neutral for long periods is certain to deplete the HV battery. Then you've got real problems.

    Either or both of the electric motors, MG1 and MG2, are almost continuously in motion, and you would be oblivious to any starting and stopping because they are silent. What you might observe is the stopping and starting of the ICE, because it does make a sound, but the ICE does not have a starter like a non-hybrid car and there are not really any parts to wear out, with all the stopping and starting, because that is what it is designed to do.
     
  4. bisco

    bisco cookie crumbler

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    trade for a prime?
     
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  5. The Professor

    The Professor Senior Member

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    Yeah this isn't a good idea :D

    The Prius is a hybrid. It has been explicitly designed around the very idea of the ICE frequently stopping and starting. It has a different type of engine and different engineering around how it's started. It starts and stops all the time when you're driving normally - that's the whole point. The engine temperature is maintained in the situation you mentioned, so it's not like you're damaging your ICE due to the engine oil not being hot.

    Then there's the poor HV battery. The higher the level you charge a Li-Ion or NiMH battery to, the more you shorten its life. This is one reason why it's relatively rare to see it 1 bar from being full and even more rare to see it 0 bars away from full. So by doing what you suggest, you are going to shorten the life and reduce the capacity of the HV battery. Those batteries are expensive.

    Meanwhile, you're losing energy to excess heat from the ICE from it having time to heat up to a higher temperature and increasing electrical losses due to it being less efficient to charge a nearly-full battery compared to, say, a half full one.
     
  6. fuzzy1

    fuzzy1 Senior Member

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    This operation puts less strain on the electric motor-generators than it puts on the gasoline motor, which also must run to charge the battery.

    If they can build a gasoline motor to handle this operation and ordinary stop-and-go traffic use, then they can build an electric motor to handle such use at least as well.
     
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  7. MIkeDr

    MIkeDr Active Member

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    I liken neutral to car wash mode. Because the only time I put it in neutral is when going through an automated car wash.
     
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  8. alanclarkeau

    alanclarkeau Senior Member

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    As others have said - except for exceptional circumstances - "N" is never used.

    And put this on your MFD - it's far more useful than the default:
    upload_2021-3-2_8-31-11.png

    You can also get a massive version on the Entertainment system - useful for entertaining passengers who don't understand a Hybrid but want to.

    [I find this relatively useless - the graph is in your HUD anyway: upload_2021-3-2_8-33-3.png ]
     
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  9. Kitats

    Kitats New Member

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    Thanks for all the responses definitely answered my question. I was just worried because the electric motor never charged above 3or 4 bars I think it was. Didn't occur to me I guess that this was actually a feature of extending the battery life and that it was designed to do that.
    I sit a lot with my engine in idle since many times these days it's almost impossible to find a place to sit other than if you own a home or sit on the ground.

    Got one of those power station batteries though so I can run electronics without the car being on
     
    #9 Kitats, Mar 2, 2021
    Last edited by a moderator: Mar 2, 2021
  10. Kitats

    Kitats New Member

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    Yeah I love my hybrid I still got a lot to learn about it though :).
     
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  11. Mendel Leisk

    Mendel Leisk Senior Member

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    I like neutral for gently rolling an angled front wheel into contact with curb, when parking on steep hills.

    AB0F3DDD-9C82-47CD-BEF9-A3F8A0CE7CB5.jpeg
     
  12. jerrymildred

    jerrymildred Senior Member

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    Another reason for this that hasn't yet been mentioned is that when you brake, much of that energy goes back into the battery. If there's no room in the battery then the car uses friction brakes for the entire stop like those kludgy antiques other people drive.

    Exceedingly unnecessary. Just keep it in READY mode and in park. People sleep overnight with the AC running in their Prius. The DC/DC converter in the inverter will keep the 12V charged from the traction battery. When the traction battery gets to a certain point, the ICE will start and run briefly to recharge the traction battery. Having a bigger 12V won't make a bit of difference. (Except for burning more fuel while charging the bigger 12V.)

    Same here. And I've had a Gen 2, a PiP, and a Prime and my wife has a regular Gen 4. :D

    Or scrubbing the rust off your brake rotors if you can't wait for them to be scraped clean in normal driving. (y)
     
    #12 jerrymildred, Mar 2, 2021
    Last edited: Mar 2, 2021
  13. alanclarkeau

    alanclarkeau Senior Member

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    And more weight to cart around.

    There are a few threads on PriusChat about PRii left running overnight, or while in shopping, at work. Here's one thread - a few stories:

    Car Left "On" at Work for 9+ hrs | PriusChat

    Easier to search on GOOGLE - but include PriusChat in the query.

    I'm sure I read about a PRIUS which was left at the airport for a week or so "ON" - and they returned to it after the week to a nice cool car, and ½ a tank of Petrol. But I can't find it.
     
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  14. Kitats

    Kitats New Member

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    Oh I meant a portable power station. I use a goal zero 500x

    [​IMG]
    which is about the size of a small radio. Very compact and solar panels available. Great for boondocking!

    but yeah obviously like you said car is better for air conditioning but it's good to have a backup or alternative :)
     
  15. Kitats

    Kitats New Member

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    I can't tell you how many times I've gotten out of my car and left the engine on accidentally because it's so quiet and the car beeps and I'm trying to figure out if I left my keys inside or the car in ready mode.
     
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  16. jerrymildred

    jerrymildred Senior Member

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    Or traffic is so loud that you can't hear the car beep. When I park at work, most of the time I can't hear that the doors locked when I get out; I have to watch the lights or try opening a back door to be sure.
     
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  17. alanclarkeau

    alanclarkeau Senior Member

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    Or - move to Australia - where you can watch the mirrors fold.
     
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  18. Mendel Leisk

    Mendel Leisk Senior Member

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    That’s my trick too.
     
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  19. sam spade 2

    sam spade 2 Senior Member

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    Like the simple fact that it does NOT run on the battery alone for more than about 5% of the time it is moving.
    And that ALL of the energy used ultimately comes from the engine running and burning gasoline.
    The overall design just uses the gas engine more efficiently.
    There is no free lunch (energy).
     
  20. rjparker

    rjparker Tu Humilde Sirviente

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    I and others including a prominent Toyota mechanic believe long idle periods on a regular basis is not good for the engine. On my gen3, extended idling, usually for ac in the summer while waiting, causes thermal cycling of the engine coolant and by extension, the engine. I have seen 195f while driving quickly cool to 150f-160f within minutes idling only to heat up again during the hv charge cycle. This repeats three or four times an hour.