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Weakened Hybrid Battery

Discussion in 'Gen 3 Prius Main Forum' started by MelonPrius, Jul 9, 2024.

  1. MelonPrius

    MelonPrius Senior Member

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    This community was very helpful with advice on whether I needed to worry about my original water pump so I'm going to ask about my weak hybrid/traction battery.

    I make several trips a year from Las Vegas to Southern California, which is a 4.5-5 hour trip through mountains and desert landscape. A good portion of the trip is made through uninhabited land in 100+ degrees, where you don't want to experience a break down.

    My car is 10.5 years old, it has brand new tires, there are no leaks, the engine isn't burning oil, fluids are fine, EGR is clean, and I have a new inverter. The concern is the traction battery, which is giving me around 42-45 mpg for a tank, from an average of around 50 mpg during it's peak. Dr Prius has my battery at around 38% left in it's estimated lifetime, they recommend a new battery when it hits 30%.

    My question is what happens if my traction battery dies when I'm in the middle of nowhere? I've read that I can limp along with the engine, but how far can I drive the Prius just using the ICE engine? Can I make it up mountain passes and how fast can I drive? Or does the Prius just become a regular ICE car and can be driven like one until I get a replacement battery?

    (I'm leaving this week during a heat wave, so I'm hoping to hear something reassuring. I'm anticipating getting around 47 mpg (calculated) for this trip. TIA)
     
  2. bisco

    bisco cookie crumbler

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    generally speaking, the battery dies slowly and will give you plenty of notice. even when it poops out and the car won't start, disconnecting the 12v for a minute resets the codes and you are on your way.
    now would be a good time to consider a grid charger to recondition the battery and extend its life, unless you'd prefer to invest the money in a new battery.
    see hybrid automotive.com or maxx volts.
     
  3. Grit

    Grit Senior Member

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    Run an app that shows the hv battery temp and turn on the fan intake with the AC up before you begin regen downhill. I do that thru the grapevine and going to and back from SF. The battery heats up fast during summers when I make those trips.
     
  4. MelonPrius

    MelonPrius Senior Member

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    2014 Prius
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    Three
    Uh oh. My morning drive to the local park usually gives me 60 mpg. This morning, I achieved 33 mpg. I quickly did a full battery test via Dr Prius and received a battery warm warning. I’ll update later but I’m getting more concerned.

    does anyone know what the battery warm warning means?

    Update: I'm going to get a new OEM battery installed. The prices that I have been receiving have a big variance between the different dealers in different states close by to me so it pays to shop around. I'll update this later about the experience in getting a new hybrid battery.
     
    #4 MelonPrius, Jul 10, 2024
    Last edited: Jul 10, 2024
    bisco likes this.
  5. bisco

    bisco cookie crumbler

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    make sure they clean the cooling fan and check the connectors for corrosion
     
  6. Andrew213

    Andrew213 New Member

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    Location:
    Manassas VA
    Vehicle:
    2012 Prius
    Model:
    Two
    Does anyone know if this is a healthy battery? I test drove a 2012 Prius 3 for about 30 minutes and this was what I got back from my OBD2 link.
    It’s listed at $11,995 and has 79,000 miles.
    It rides great but I want to make sure the hybrid battery is healthy before I buy it.
     

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  7. bisco

    bisco cookie crumbler

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    that looks about right for a 12 year old battery, but don't count on it lasting much longer, and don't forget the brake booster and head gasket issues.
    all the best!