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Second start of the day in summer vs. winter

Discussion in 'Prius c Main Forum' started by Deleted member 111882, Mar 24, 2016.

  1. So I feel as if there should be a discussion about this somewhere. Say that I start my hybrid first thing in the morning, travel 2 miles, then turn off the car and go to wherever, maybe the supermarket. During that first trip, the battery gets used because of the warm-up cycle... more so in the summer than in the winter, since I see the battery deplete a bar or two. Why is that?

    Anyway, I come back after maybe 20 minutes, turn the car on for the second start of the day, and take off. In the summer, the second warm-up cycle is much longer and I often find myself depleting the battery to 2 bars... after like another minute, finally the engine kicks on, roars, and starts recharging the battery. Why is the hybrid designed to do that? I just feel like I would get much better fuel economy just waiting the extra minute until the generator kicks in, so that I'm not draining the battery. Whereas in the winter, the battery usually stays around 6 or 7 bars and never drains, and the engine never has to roar. Why can't the hybrid just do that in the summer as well?
     
  2. Mo G

    Mo G Member

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    From what I understand, you are wondering why the engine does not kick on sooner in the summer, to charge the battery, correct? The engine is already 'warm' enough to not kick on, until it is needed. Are you are referring the engine not being on as the 'warm up cycle'? Meaning it stays off as long as possible while you drive on battery alone. You could always go faster than 42 MPH or try to get up to speed a little bit quicker to get your engine to kick on. Or if it's warm in your area, turn the AC on, and the engine should turn on, unless in ECO-mode.
     
  3. I'm referring to the first minute or so after you start the car, the engine turns itself on, and just stays around 1280 rpm, that's the initial warm-up.
    Like the second time I start the car, during the initial warm-up, I can hit the gas and go but if I do it in the summer, the car just uses up battery and it drains down to 2-3 bars, whereas in the winter, the car uses both some battery and the engine so the battery doesn't go below 5 bars. Why can't the car just do that year round? What benefit is there?
     
  4. Mo G

    Mo G Member

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    I have a 2012, mine doesn't actually like that unless I feather foot the gas pedal. Winter time, the engine cools down below optimal 'warm' temps, so it tends to stay on. In the summer, it stays warm, and doesn't kick on. Try using the screen which tells you how hard your pushing the pedal , if you push past economic mode, engine turns on. Or if you are traveling faster than 42MPH (sometimes 46 MPH) the engine will kick on.


    More so to your point, the engine will stay on the same length of time to charge the battery unless you are regen braking more in one of the two seasons. If the engine has to stay on from 2 bars of battery and wait to turn off athe full, or turn on at 5 bars and top up the battery. It will be more frequently used and for a lot shorter period of time if it always started at 5 battery bars and topped up. That could be the reason. Not sure, but make sense, to have the gas engine on as less frequent as possible. But when on, use it to its full potential, and then off again. Instead of on, off, on ,off, frequently causing MPG to take a greater hit, I suppose.
     
  5. MauroneRelax

    MauroneRelax Junior Member

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    Hi skylis, its because in Winter, engine is more cold and warmup takes longer.
    May also warmup longer if the heater is on.
    Engine charges battery when you are idle or coasting in warmup to speed up, so longer recharge in winter.
    Except the first minute, when burns differently and is too weak to not drain battery.
    in P and Ready you can start engine early kicking accelerator and spend a minute to get ready before moving.
    Not moving the first minute saves battery.
    Sometimes if the engine is on and if you don't accelerate at least half eco, it is moving electrically.. Is it your case?
    the target temperature depends also from starting one, 20 minutes is short time.

    I expect opposite
    To prepare right conditions for the right emissions sooner.
     
  6. I am confused. The car should be able to prepare the right conditions for the right emissions anyway. Like if it's the winter and I hit the gas to maybe 3/4 green, during and just after the warm-up cycle, the battery stays around 5-6 bars, and the engine stays below 2000 rpm. But if it's summer, the battery depletes to 2 bars (contrary to your expectation) during the warm-up cycle because it won't use the engine like it did so conveniently in the winter warm-up cycle, then the engine blasts up to 3000 rpm to waste more fuel to recharge the battery. How is that cycle supposed to be any better than in the winter? That's what I don't get. To me it feels like, compared to the winter cycle, the summer warm-up cycle (1) depletes the battery just to recharge it, which seems pointless, (2) uses so much more gas to recharge, which wastes more fuel, and (3) puts more wear on the engine because of the higher rpms during recharge. So, what's the logic for two different types of recharge cycles? How is that the "right conditions for the right emissions sooner"?
     
  7. MauroneRelax

    MauroneRelax Junior Member

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    It is not logic, my car never depletes battery that way and in summer warmup is very fast. I heard of card left under the sun in hot summer days that prevented using battery until cooled by air conditioning.
    But, the point can be the air conditioning, its electrically operated and could drain your battery, maybe this is your case?
     
  8. Alright try this:
    1. In the summer, go to some local place, maybe travel for 1 mile.
    2. Restart the car.
    3. Take off going uphill during warm-up cycle filling green arc for 30 seconds. (In the winter, this doesn't happen.)
    4. The battery will deplete in the summer.
    No one else has seen this?

    BTW: I'm using this as just one example, since many people don't have a Scan or UltraGauge, but it's really when you start the car and the coolant temp is like 100-130 or so on a second (or third, fourth, etc.) start.
     
    #8 Deleted member 111882, Apr 1, 2016
    Last edited by a moderator: Apr 4, 2016
  9. [3 weeks later]

    Well, anyone?
     
  10. bisco

    bisco cookie crumbler

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    have you studied hobbits stages of warm up?
     
  11. Nevermind, this is going nowhere. I just expect that the summer warm-up cycle should be more like the winter cycle. That MauroneRelax experiences more battery drain in the winter than the summer whereas I have always experienced the opposite during warm-up is even more perplexing to me. Not to mention in the dead of winter I've never seen it go below 5 bars anyway.

    All I've learned from this thread is somehow the engineers have some mysterious logic along these lines: "it's more efficient to let the battery go down from 6 to 2 bars in the summer warm-up cycle when they gun the gas so that the engine can then rev way the freaking hell up to 3000-4000 rpm while the throttle persists after the end of the warm-up cycle thereby wasting more fuel, but let's make sure that doesn't happen in the winter so the engine stays around 2000 rpm for the same amount of throttle so it's more efficient," yet I still don't get what that logic is, the hobbit stages discussion that I've seen didn't explain the logic, it's the same behavior with nearly every single Prius c out there on the road today, and yet no one here seems to know what I'm talking about. This is going nowhere so just forget it.
     
    #11 Deleted member 111882, Apr 24, 2016
    Last edited by a moderator: Apr 24, 2016
  12. wjtracy

    wjtracy Senior Member

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    In my mind it correlates to if A/C is on the batt can drain bars pretty quickly in summer if you pull out without warming a little. Also I believe the bars are not equal capacity so those middle bars can go away fairly fast. In any case, assuming c is same as other Prii (generic) Bob Wilson may be able to answer.
     
  13. rjdriver

    rjdriver Active Member

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    I agree with wjtracy. Heating and cooling are the two variables effecting what you see. The computer is programmed to never ever let the battery get below 2 bars. Perhaps the higher revs in the summer are because of the urgency to prevent that from happening when the engine kicks in at 2 bars, rather than when it kicks in at 4 or more bars in the winter. Maybe the engineers saw that 2000 rpm was not always sufficient to recharge while the air conditioner was in use, and that using a little extra gas to extend battery life was more important than the very brief effect it would have on gas mileage.

    If you are not using the air conditioner in the summer, then this theory goes out the window. You can of course test this by recreating these two situations, being careful to eliminate the two variables, heating and cooling of the cabin, through temperature control adjustments.
     
  14. Mendel Leisk

    Mendel Leisk Senior Member

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    Have you considered how that might sound to the uninitiated? ;)

    Capture.JPG
     
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  15. bisco

    bisco cookie crumbler

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    much more interesting, to be honest.:p