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Left my Prius in the garage (2 Months!..)

Discussion in 'Gen 3 Prius Main Forum' started by iskoos, Sep 2, 2018.

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  1. iskoos

    iskoos Active Member

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    I left my 2010 Prius III (148k miles) in my garage in Florida and left the state. I thought I was gonna be back in about 30 days.
    It has been 2 months now and I am still not back. The car hasn't been run.

    When i left the car, it had 5 out of the 8 bars showing for the hybrid battery. And the aux battery was new. (Replaced just a week before my trip).

    The car was left unlocked in a garage.

    My friend is planning on stopping by to start it next week. My return will not happen for another 30 days.

    What are my chances that it will start?
     
    #1 iskoos, Sep 2, 2018
  2. bisco

    bisco cookie crumbler

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    it will probably be fine.

    big issue: is the garaged air conditioned?

    the 12v will be fine, if it was fully charged when installed.

    the 2010 hybrid battery is on the cusp of degradation and sitting in heat won't help.
    these are things we learn to deal with as prius owners.

    i'll go 90% will start, all the best and please let us know!(y)
     
    #2 bisco, Sep 2, 2018
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  3. sam spade 2

    sam spade 2 Senior Member

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    Excellent I think unless the new aux battery wasn't ever charged fully.

    If your friend does start it, he needs to drive it around for about a half hour to get the aux. charged up again.

    It really doesn't matter how many "bars" the HV battery shows.
     
    #3 sam spade 2, Sep 2, 2018
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  4. iskoos

    iskoos Active Member

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    I was under the assumption that the aux battery gets its charge from the HV battery when the car is not in use. That's why I stated that HV was 5/8 full when I left.
     
    #4 iskoos, Sep 2, 2018
  5. iskoos

    iskoos Active Member

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    I plan on having my friend start the car, let it go through its cycle and then I am gonna have him connect a float charger to aux battery.
    All this thinking that the car will start.

    I will absolutely let you know (with every detail...)
     
    #5 iskoos, Sep 2, 2018
    Last edited: Sep 2, 2018
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  6. jerrymildred

    jerrymildred Senior Member

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    Only in READY mode. I agree that you're probably OK and that your friend should drive it for at least a half hour to get everything charged back up.
     
    #6 jerrymildred, Sep 2, 2018
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  7. padroo

    padroo Senior Member

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    If the 12 V battery is dead does your friend know how to properly jump it?
     
    #7 padroo, Sep 2, 2018
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  8. fuzzy1

    fuzzy1 Senior Member

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    A half hour won't add much charge, as the Prius 12V charging system is slow.

    And while good for the engine, it doesn't actually need to drive around at all to charge the 12V. The time spent in READY is what matters, and counts even when sitting still in Park and the engine not spinning. The HighVoltage -> 12V inverter is running the whole time the ignition is READY.
    If you won't be back for a month, I'd second the float charger idea, and even rank it higher than starting the engine.
    As Jerry already pointed out, this is the opposite case, that charging happens only when the car is IN use. When off, the HV is disconnected and isolated, subject solely to its own internal self-discharge. For Prius NiMH batteries, this is much slower than the 12V self-discharge plus parasitic loads.

    The HV battery should usually be fine for many months. But considering the age of your HV battery and the climate in which it is stored, an engine warmup cycle and associated HV chargeup might be a good idea.
     
    #8 fuzzy1, Sep 2, 2018
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  9. iskoos

    iskoos Active Member

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    NO he doesn't:) But I can instruct him...

    I am really not so worried if the aux battery runs down only. There is a way to recover it. My only worry is the HV battery. Because I know if it gets too low, the car will need to get to dealer.

    If you guys saying there is no drain on HV battery, I am gonna feel so good...
     
    #9 iskoos, Sep 2, 2018
  10. iskoos

    iskoos Active Member

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    Thanks fuzzy1. You are confirming that there is no parasitic load on HV battery. Then I should be good.
    I should have just disconnected the aux battery and I didn't need to worry about anything at all.
     
    #10 iskoos, Sep 2, 2018
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  11. sam spade 2

    sam spade 2 Senior Member

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    Make that when the car IS in use and then you have it right.
    There is NO drain on the HV battery when the car is OFF.
    There is only a tiny little drain on the 12 V aux. battery when OFF and part of that is internal to the battery itself.

    AND.....if the small charger you intend to use is an automatic tender type charger, then there really is no need to start the car at all. Just connect the tender and wait for "daddy" to get back home.
     
    #11 sam spade 2, Sep 2, 2018
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  12. iskoos

    iskoos Active Member

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    Okay. I am here with an update.
    My buddy stopped by my home yesterday. First thing he checked was the aux battery voltage. It was 12.06volts (about what I was thinking).
    Car was parked in hot Florida garage since June 28th. The aux battery was new and fully charged when parked.
    I had him power on the car. Car powered on fine and engine started in 15 seconds as it was supposed to. There was knocking for about 2 seconds (I heard it over the phone) then engine ran smooth. I had this knocking happened 2 more times in December and I read enough about it. (Already familiar with the danlatu fix and OCC threads:) I bought an OCC but still didn't have time to install it yet.
    Anyways other than the quick knocking, engine ran fine for about 3-4 minutes and stopped. The hybrid battery was at 5 bars when I left it. And it was at 4 bars yesterday. After engine stopped, it was still at 4 bars.
    My buddy powered off the car and I had him check the aux battery voltage again. It was around 12.4volts. I had him connect my float charger to it and he left.

    I am fine(y) As many of you stated, there is almost no drain on hybrid battery. It was pretty much at the level I left it 2.5 months ago. And I am pretty sure it would have gone for several more months.

    As a future reference, if you will be gone for a while, the only thing that needs to be done is either disconnecting the aux battery or hooking up a float charger to it. No problem for the hybrid battery (even after 8 years...)
     
    #12 iskoos, Sep 10, 2018
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  13. Prodigyplace

    Prodigyplace 2025 Camry XLE FWD

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    The other thing would be to turn off the SKS so the car does not keep searching for a fob, causing an unnecessary drain on the 12V battery..
     
    #13 Prodigyplace, Sep 10, 2018
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  14. ericbecky

    ericbecky Hybrid Battery Hero

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    I would top off the hybrid battery by power-braking.
    Get all the green bars full.

    No reason to leave it low when parking it so long.
     
    #14 ericbecky, Sep 10, 2018
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  15. Grit

    Grit Senior Member

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    How does one do that? This is my first time hearing this method.
     
    #15 Grit, Sep 10, 2018
  16. ericbecky

    ericbecky Hybrid Battery Hero

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    Parking brake on
    Car in ready mode.
    Foot on the brake
    Shift to drive keeping foot on the brake
    Foot on the accelerator while keeping foot on the brake.
    Turn car off when battery is full.
     
    #16 ericbecky, Sep 10, 2018
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  17. fuzzy1

    fuzzy1 Senior Member

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    These batteries don't get their best longevity while sitting full. Some mid-level charge is best.

    Yes, the control system and battery SOC meter don't use or display the full rated battery range, setting some margin as off limits. But you can do better by leaving the SOC gauge at its preferred operating level. On my Gen3, that is 6 bars, not the full 8. The Gen2 should be similar.

    If your absences are not long enough for the HV battery to run down to 2 bars, then I wouldn't start the absence with higher than 6.
     
    #17 fuzzy1, Sep 10, 2018
  18. ericbecky

    ericbecky Hybrid Battery Hero

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    The soc will be about 75% if you fill both green bars.
    But it will not stay at 75% if left for a long period because it self-discharges.
    Especially if it is an old, weak battery.
    This car's pack is 7-8 years old.

    I would want 100% confidence that the SOC does not drop below the minimum SOC needed to start the car. So I would fill it.

    That said, yes, if you have a HV battery maintainer, then go ahead and store the pack at a lower SOC (say 40% SOC). As the pack self discharges the charger will periodically bring the voltage back up to 40% whenever the voltage drops as needed.
     
    #18 ericbecky, Sep 10, 2018
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  19. Maarten28

    Maarten28 Active Member

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    There is absolutely no need for that. 2 bars is 40%, 6 bars is 60%, so 3-4 bars is 45-50%. Well within normal limits and fine for a battery.
     
    #19 Maarten28, Sep 11, 2018
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  20. Toyo38289

    Toyo38289 Junior Member

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    I have never heard of that before...

    Does this put the car in some type of special mode for battery charging ?

    In a conventional vehicle, this procedure would place significant stress on several different drivetrain components.
     
    #20 Toyo38289, Sep 13, 2018
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