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Battery charge

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by gypsiqueen, Jul 29, 2024 at 11:01 PM.

  1. gypsiqueen

    gypsiqueen New Member

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    Vehicle:
    2014 Prius
    Model:
    Three
    I hope this question is OK. I inherited a 2014 Prius 3 from my dad. He only drove it 4,000 miles, and had the electric battery hooked up to a charger when it was sitting (years). It has just over half a capacity when doing normal driving. My question is, when we were driving through stop and go traffic on the mountain pass last week, the battery dropped to 2 bars. Is this normal? I completely freaked out because I don't want it to die in the middle of a mountain pass. Will it charge itself when it gets that low? We're looking at 2 hours of stop and go traffic on the way back home over the other side of the pass. Is it ok if it sits that low for hours? Or should I have a new battery put in? Please no super technical answers though, I'm still working on reading the manual, but I need to know since we're driving it soon.
     
    #1 gypsiqueen, Jul 29, 2024 at 11:01 PM
  2. OptimusPriustus

    OptimusPriustus Active Member

    Joined:
    Jul 31, 2021
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    Finland
    Vehicle:
    2010 Prius
    Model:
    N/A
    Welcome to Priuschat. Prius has two batteries: 12v traditional car battery and high voltage drive battery. That 12v battery is relatively cheap (couple hundred) and practically any shop can replace it in no time. I presume it was this 12v battery that had been charged when car was storaged since normal DIY chargers can be used. You don’t get any reading of this 12v battery from the dasboard. When it’s done car simply won’t boot up and doors need to be unlocked with traditional key.

    The drive battery is completely different animal. Cost couple thousand but usually last very long if car is used normally. Being parked for several years is not normal. I highly recommend to have both of your batteries health checked at proper shop. Perhaps have whole car checked for safety sake (brakes etc) if car has been parked many years.

    Edit: drive battery charge go up and down during driving, it is normal. Car use the charge that is available and recharge during braking and by running the combustion engine when needed.
     
    #2 OptimusPriustus, Jul 30, 2024 at 7:29 PM
    Last edited: Jul 30, 2024 at 7:34 PM
  3. bisco

    bisco cookie crumbler

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    boston
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    2012 Prius Plug-in
    Model:
    Plug-in Base
    just over half capacity is normal, and dropping to 2 bars with engine cycling on and off to keep it there in stop and go traffic is also normal. and there may be times when the battery completely fills, depending on driving conditions.
    are you saying you have a 10 year old car with 4,000 miles? if so, that's wonderful!
     
    #3 bisco, Jul 30, 2024 at 8:34 PM
  4. Eddie25

    Eddie25 Active Member

    Joined:
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    Location:
    IL
    Vehicle:
    2011 Prius
    Model:
    III
    The battery does charge itself when it gets low. The "hybrid" aspect of the car is that it uses a combustion engine and a high voltage battery in conjunction with each other. The battery (discharge) helps the engine and the engine helps the battery (charge). It's constantly going from high to low charge and back. If there are no trouble code lights or drivability concerns I wouldn't worry about it. Yes, it's OK for the car to sit with the battery at a low charge. It's not considered great for the battery if the car sits for an extended period, but like a week or so here and there isn't terrible.
     
    #4 Eddie25, Jul 30, 2024 at 11:00 PM
  5. JohnPrius3005

    JohnPrius3005 Active Member

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    Location:
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    Vehicle:
    2004 Prius
    Model:
    II
    You'll be fine!
    You have a great car with so few miles.
    Spend some effort trying to locate an independent Prius shop you can trust. Interview them extensively and ask to speak to a few of their customers.

    Avoid all Toyota dealers unless you personally know the owner.

    Do this in advance of needing help.

    There are good people out there but they are pretty well hidden.
     
    #5 JohnPrius3005, Jul 31, 2024 at 1:54 AM
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