Is there a way to disable Smart Key in Primes when going on vacation?

Discussion in 'Prime Main Forum (2017-Current)' started by NEHiker, Jul 12, 2018.

  1. NEHiker

    NEHiker New Member

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    With summer vacation season upon us, I'm wondering whether it will be bad for the battery in my new Prime if the Smart Key functionality is left "enabled," while the car is not used for a couple of weeks. It seems like in older Prii there was a way to manually disable the Smart Key sensor (and later re-enable it). Does anyone know if that's possible with the Prime? Or maybe it won't be an issue in the first place! Thanks in advance everyone!
     
  2. schja01

    schja01 One of very few in Chicagoland

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    It's AutoMagic:
    2018-07-12_140723.png
     
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  3. NEHiker

    NEHiker New Member

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    Thanks so much! I should file my post under "read the user's manual, dummy!" LOL!
     
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  4. Washingtonian

    Washingtonian Active Member

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    It sounds like if you don't use the smart key for a period of time (ten minutes, five days or ten days, take your choice), it automatically goes into a battery saving mode to save its battery. Not sure it is worth the effort to place it into that mode by pressing the unlock button and holding the lock button. My concern when I go away for a month or two is the 12V battery. I hook it up to a battery tender and also make sure my traction battery is not charged when I am gone. Incidentally, has anyone had their Prime long enough to have to change the battery in the smart key?
     
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  5. schja01

    schja01 One of very few in Chicagoland

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    I have gone through Toyota 5 cars with smart key fobs and changing batteries is a snap.
    Now I change them every two years whether they need it or not.
     
  6. Mendel Leisk

    Mendel Leisk Senior Member

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    Fob issues aside, there's always a background drain. Two weeks will have some impact. You might consider:

    1. Hook it up to a smart charger, one that can be left on indefinitely. This presumes you've got a secure garage.

    2. Disconnect the 12 volt battery's negative lead. This'll require unlocking the car with the physicial key, and if you're not in a secure garage where it can be left ajar: a crawl through the car to release the hatch. Read up as to where that release is, try it out, in advance.

    Someone will likely question the necessity for all the above, and yeah, a battery in good shape at the outset, it probably will be ok, but it will take a bit of a hit.
     
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  7. bisco

    bisco cookie crumbler

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    i have left my sks on while away for two months every winter for the past 6 years.
     
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  8. PT Guy

    PT Guy Active Member

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    Is this useful? Run the traction battery down to its minimum and store it that way for a few months?

    A good general rule-of-thumb is to put a maintenance charge into a stored lead acid battery (a typical car or RV 12 volt battery) once a month. Even two months without a charge is no problem if there is no parasitic drain on the battery. Of course, an automatic trickle charger full time works very well.
     
  9. schja01

    schja01 One of very few in Chicagoland

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    Can you charge a totally discharged traction battery on a Prime with the wall charging cable? A discharged traction battery on the traditional Prius required special charging equipment.
     
    #9 schja01, Jul 15, 2018
    Last edited: Jul 15, 2018
  10. Washingtonian

    Washingtonian Active Member

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    I guess it is useful as I learned about it from this forum. I had posted that I had left for a month with my traction battery fully charged and when I returned it still had exactly the same charge as when I left. A couple of "experts" stated that it was not good for the life of the battery to leave it fully charged for a long period. Of course, we are not talking about a lead acid battery here.
     
  11. CharlesH

    CharlesH CA HOV Decal #5 on former PiP

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    It is not good to leave a lithium-ion battery like in the Prime fully charged for an extended period of time. I am not sure exactly what charge level Toyota recommends when going on vacation. Half charged, maybe? While sitting with the system off, there is zero load on the traction battery, since it is disconnected by the control system. And I don't think that internal self-discharge is an issue with them.

    OTOH, lead-acid batteries like to be fully charged. The problem with it on a vacation is the various little "parasitic" loads, like the clock and the wireless key and (on the Advanced) the Safety Connect cell phone. I think the latter two turn themselves off after a while.
     
  12. SteveMucc

    SteveMucc Active Member

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    couldn't you just plug it in?
     
  13. schja01

    schja01 One of very few in Chicagoland

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    I hope so.
    The question I had was can you recharge a totally dead traction battery of a Prime via the charging port?
    I wondered because if a conventional Prius traction battery is drained you can't start the ICE to recharge it
    and it requires special charging equipment that only a dealer typically has.
     
  14. wjtracy

    wjtracy Senior Member

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    Historically Gen2 had a SKS on/off button under the steering wheel to preserve the 12v battery of the vehicle on long sittings. After that Gen3+ I think it was automatic, so there is not much to do in the Prius itself (as @bisco has stated above) except some like to keep the 12v on trickle charge just in case of a drain source (per Mendel).

    Re: HV Batt - Another rare thing with Gen2, at one of the national labs, there was a huge downhill mountain on the way to work, so the employees with Prii were coming in with HV batt fully charged and then parking in the hot sun. This killed a few HV batts. So I try to be a few bars down from full before parking in the Sun, but almost never happens anyways. Presumably Toyota may have adjusted Gen3+ programming to avoid that over-charge situation..
     
  15. bisco

    bisco cookie crumbler

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    you cannot recharge a dead hybrid battery from the charging port. a lot more goes into it, and i don't even think we have seen it done to any toyota li-on.
     
  16. bisco

    bisco cookie crumbler

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    clarification:

    running the hv battery down to it's lowest level is simply using up the wall charge until the engine comes on.
    you cannot totally deplete the battery, it is just left in the same level as a regular prius.
     
  17. CharlesH

    CharlesH CA HOV Decal #5 on former PiP

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    I think the only way to totally deplete the traction battery in a Prius is to operate the car with no gasoline. And even then, I don't know if the Prime will discharge it so low that it requires a proprietary charger that only dealers have to get it going again. You could do that with earlier Prius models; don't know about the Prime.
     
  18. bisco

    bisco cookie crumbler

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    we can only assume that @bwilson4web has already tested this.;)
    (or try and use the search feature):rolleyes:
     
  19. schja01

    schja01 One of very few in Chicagoland

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    leave it in neutral with heat pump running. Prime won’t charge in neutral.
     
  20. SteveMucc

    SteveMucc Active Member

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    ok, so if the battery was entirely depleted (not sure how to do this, actually... sit for a decade?) why would the wall charger not do it? Ultimately it's simply a li-ion battery. Sure you'll need to power the charger electronics. Not sure if the wall charger will do this or if the 12V is all that's necessary. Granted, they could run the charger off the inverter (creating a chicken-and-egg problem), but that seems like making things more difficult at the factory than they would otherwise need to be. Why force things to use an entirely new charging mechanism than would be needed if you designed it not to be.

    what exactly in the design makes you think it can't be recharged via the wall adapter?
     
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