Prius 12 volt battery: what to do if not driving for a month?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Peter Nichols, Sep 28, 2013.

  1. Peter Nichols

    Peter Nichols New Member

    Joined:
    Sep 28, 2013
    4
    0
    0
    Vehicle:
    2013 Prius
    Model:
    N/A
    I can't seem to get a consistent answer to this question. I have a new 2013 Prius, just the regular model, and will be going out of the country for a month. Should I disconnect the 12 volt battery, both posts, only the negative/black, only the red/positive. If not, should I use a trickle charger, and is there a particular model/kind I should use?

    I cruised my dealership service department and got four answers: 1. the main battery, the big one, will keep the 12 volt battery charged, so no need to do anything, even for a month; 2. the 12 volt will probably be okay for any time less than a month, if the car is stored in a garage in which the temperature is above 43 degrees F; 3. to be safe disconnect both posts of the 12 volt; 4. disconnect only the red/positive post.

    Can anyone help me with this, please?
     
    #1 Peter Nichols, Sep 28, 2013
  2. rdgrimes

    rdgrimes Senior Member

    Joined:
    Jun 7, 2013
    1,740
    448
    4
    Location:
    New Mexico, USA
    Vehicle:
    2018 Prius Prime
    Model:
    N/A
    You'd probably be OK doing nothing, if its fully charged to begin with.

    There are a number of "battery tenders" designed for this purpose if you want to use one. Disconnecting it will accomplish nothing.
     
    #2 rdgrimes, Sep 28, 2013
    TsKarma likes this.
  3. Peter Nichols

    Peter Nichols New Member

    Joined:
    Sep 28, 2013
    4
    0
    0
    Vehicle:
    2013 Prius
    Model:
    N/A
    Thanks for your help. I have a "trickle charger". Not sure if this is different from a "battery tender". My trickle charger says it will give our 2 amps.
     
    #3 Peter Nichols, Sep 28, 2013
  4. rdgrimes

    rdgrimes Senior Member

    Joined:
    Jun 7, 2013
    1,740
    448
    4
    Location:
    New Mexico, USA
    Vehicle:
    2018 Prius Prime
    Model:
    N/A
    I'd avoid old school trickle chargers, since you don't know if its smart enough to shut off. If the documentation for it specifically states it can be left on for a month, its OK. The "tender" is designed to monitor battery condition and only charge if needed.

    Do you have someone checking on the house while you're gone? If so, just have them plug it in every week or do for a couple hours.
     
    #4 rdgrimes, Sep 28, 2013
  5. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    57,961
    39,991
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Newer, "intelligent" chargers can be left on indefinitely. I've used a CTEK 3300 charger for protracted hook up, around 2 weeks.
     
    #5 Mendel Leisk, Sep 28, 2013
  6. xliderider

    xliderider Senior Member

    Joined:
    Apr 19, 2012
    8,001
    3,192
    0
    Location:
    Honolulu, HI
    Vehicle:
    2011 Prius
    Model:
    Three
    The main battery is not connected to the 12v battery when off, so it can't maintain it's charge.

    If you have SKS, you should disable it so the system doesn't use battery power looking for the key fobs. I believe it's in the manual how to turn SKS off.
     
    #6 xliderider, Sep 28, 2013
  7. Peter Nichols

    Peter Nichols New Member

    Joined:
    Sep 28, 2013
    4
    0
    0
    Vehicle:
    2013 Prius
    Model:
    N/A

    Thanks. I really appreciate your responses, and so quickly. I have just put in an order with Amazon for a Battery Tender Plus 12v charger. Lots of very positive reviews (and a few totally negative, one even saying his garage caught on fire from one of these!?). Unfortunately, I don't have anyone entering my house while we are away, only a casual neighbor watching the outside for anything suspicious or out of the ordinary.
     
    #7 Peter Nichols, Sep 28, 2013
  8. rdgrimes

    rdgrimes Senior Member

    Joined:
    Jun 7, 2013
    1,740
    448
    4
    Location:
    New Mexico, USA
    Vehicle:
    2018 Prius Prime
    Model:
    N/A
    ;) Offer to let the neighbor drive it for you. :)
    But your purchase of a tender is prudent, you won't have your time away ruined by worrying about your baby.
     
    #8 rdgrimes, Sep 28, 2013
  9. Peter Nichols

    Peter Nichols New Member

    Joined:
    Sep 28, 2013
    4
    0
    0
    Vehicle:
    2013 Prius
    Model:
    N/A
    thank you, rdgrimes :))
     
    #9 Peter Nichols, Sep 28, 2013
  10. hb06

    hb06 Member

    Joined:
    Aug 7, 2006
    550
    15
    0
    Location:
    Huntington Beach, CA
    Vehicle:
    2007 Prius
    Model:
    II
    See my blog Energizer Battery Jumper to the Rescue. You can keep the Energizer plugged in with its built-in smart charger. It just jumped my battery from under the hood fine, and small, easy to use and store. I now have peace of mind for any future dead 12V battery locally. It also has a cig lighter socket.
     
    #10 hb06, Oct 9, 2013
  11. tplife

    tplife Junior Member

    Joined:
    Sep 3, 2013
    85
    24
    0
    Location:
    SoCal
    Vehicle:
    2011 Prius
    Model:
    Three
    A Battery Tender is just an expensive float charger. A Schumacher float charger is sold at any WalMart for under $20.00 and has the same circuitry inside without the advertising costs. I have several of them in the garage, one on the Harley, one on the Optima "house battery", an extra one if needed when the BMW X3 is not being driven. Two are 1A and one of them is selectable 1A, 2A for charging. Sadly, we Harley owners fall for all kinds of costly items, and the Battery Tender is one of them - while it's quality product, it's one of many.
     
    #11 tplife, Oct 16, 2013
(You must log in or sign up to post here.)