Urgent: 12 v battery low warning and clicking sound

Discussion in 'Gen 4 Prius Main Forum' started by Kboy, May 7, 2020.

  1. Kboy

    Kboy Junior Member

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    I retried to start the 2017 Prius after a month and the screen said 12v battery is low and went off. I was able to lock the car but I hear a ticking sound near the engine. Most likely coming from the battery itself.

    Should I immediately jump start or just leave it as is. I’m worried it could cause some issues.

    Please help.
     
  2. husami

    husami Junior Member

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    it sounds like it's low so I would jump start it. My 2017 dies after two weeks, I have something connected to the OBD2 which drained it faster. With the quarantine it's important to keep eye on the battery perhaps every couple of days.
     
  3. pianewman

    pianewman Active Member

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    I would start with jumpstarting, then decide on the future of the battery.

    How old is the battery? Have you fully discharged it before this? If so, you might want to consider replacing it, as 12V battery's lifespan;s are decreased after a few fully discharge incidents.
     
  4. Mike Moon

    Mike Moon Member

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    I have a 2017. Same thing happened to me for months. Off and on. Believe it or not the 12-volt battery (The one that’s under the hood and looks like a regular car battery) is only sold through Toyota. It’s about $300. They do that because there’s a few rules you have to follow to change out the battery and not affect the complicated electronics at the same time. But it’s easy.
    Attached is a photo of the battery that you need (from autozone), half the price of the Toyota one, and a few important instructions to follow. I just switched mine out and it worked great.
    Good luck. Let me know if you have any questions. 4AA876F4-32AF-43DB-B1F7-6CA961FABDDE.png 9BF6915D-CF57-4431-8276-CA36D61F4EB7.png 7CB0FBE5-E7B0-4146-BB90-AB1842172C7E.jpeg
     
  5. bisco

    bisco cookie crumbler

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    i would leave it until you're ready to drive again, then replace it.

    that way, you don't need a charger/maintainer/jumper
     
  6. Mendel Leisk

    Mendel Leisk Sunday driver DIY’r

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    How about trying a charger??
     
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  7. jerrymildred

    jerrymildred Senior Member

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    That's what I've done whenever I had a low battery. Except the time it was -30°F and I had to take the battery inside to thaw it before it would take a charge. ;)
     
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  8. pianewman

    pianewman Active Member

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    I would also charge the battery first, as I'm uncomfortable anytime any jump start cables come near my car. I've jump-started a car fewer than 5 times my entire life.

    The average owner doesn't even own a charger. That's why I thought a jump-start first, then drive to the dealership/repair shop.
     
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  9. tucatz

    tucatz Active Member

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    Is there a way to look at the SOC of the 12 V battery in my car?
     
  10. Mendel Leisk

    Mendel Leisk Sunday driver DIY’r

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    My 2 cents:

    The car's display's are not good. With the car on the measurement is meaningless, since the hybrid battery is supplying the volts, and you'll likely see somewhere around 14 volts. And in accessory mode the battery voltage will be reading lower than actual, since it is being drawn down by the displays.

    Better: Pop the hood in the evening*, then the next morning check the voltage with a digital multi meter.

    * If that's not practical, say the car's not securely parked: pop the hood in the morning, but at least minimize the "wake up", by going in through passenger door to pop the hood.

    Better, and avoiding the vagaries of voltage get something Solar BA9, do an electronic "load test". It will read voltage, but more importantly, will test the Cranking Amps, give you a verdict on the battery's health.
     
  11. Kboy

    Kboy Junior Member

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    Thanks for all the suggestions and help. But what’s the ticking sound from the battery. Is it ok to leave it as is and just jumpstart when I’m ready to drive?
     
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