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When should I be changing the 12V battery? 2015 prius c <39,000 miles

Discussion in 'Prius c Care, Maintenance and Troubleshooting' started by PriusCOwner001, Apr 25, 2023.

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  1. PriusCOwner001

    PriusCOwner001 Junior Member

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    I noticed my dash cam was shutting off. I have it set on low bit rate recording while parked. Saw it shut off about 3.5 hrs after parking. The voltage cut off on my dash cam is set to 11.4. I used self diagnosis mode to check 12V battery:

    11.7 after being parked for 7 hours, engine off
    14.4 after being parked for 7 hours, engine turned on
    12.2 after 20m drive home, engine off
    14.5 after 20m drive home, engine on

    I am testing out 1FPS recording instead to see how long the camera lasts before shutting off. But I am wondering if I should be looking at changing out the 12V battery soon. Haven't had any issues with car starting.
     
    #1 PriusCOwner001, Apr 25, 2023
  2. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    That's killing your 12 volt.
    Time for a new battery. If you want to confirm, have it tested with an electronic load tester. Stores selling batteries will often have these, and will test for free. Or you can DIY test with Solar BA9 or similar. If it comes up with CCA below spec (say under 300), it's time. The tester will let you know the voltage, measured CCA, and typically give a verdict, if it's viable or not.
     
    #2 Mendel Leisk, Apr 25, 2023
  3. PriusCOwner001

    PriusCOwner001 Junior Member

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    Just checked the car again, 11.9 after about 2.5 hours. I changed the cutoff for the camera to 12.4 volts if that helps the battery. I guess I'll start looking to see who sells replacement batteries near me and offers the CCA test. Manual says 11.0 to 12.5 is half charged. Is under 11.0 the point when the car will no longer start?
     
    #3 PriusCOwner001, Apr 25, 2023
  4. bisco

    bisco cookie crumbler

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    does the dashcam shut off with the car?
     
    #4 bisco, Apr 25, 2023
  5. PriusCOwner001

    PriusCOwner001 Junior Member

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    No, I have it hardwired and on parking mode. It cuts off based on the voltage cutoff I put it on. Odd thing is, I had it set on 11.4 before, the diagnostic screen showed the battery as 11.7 despite the camera shutting off.
     
    #5 PriusCOwner001, Apr 25, 2023
    bisco likes this.
  6. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    ^ Set your dash cam thus, get another battery, you’ll be good. You don’t want to lumber the diminutive battery with anything extra.
     
    #6 Mendel Leisk, Apr 26, 2023
  7. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Keep in mind that the car does a number of post-shutdown tests. Some of them are scheduled to occur hours after shutdown.

    These tests involve actuating valves and pumps, so they use electricity. Not a lot of electricity, but it is measurable. Meaning, the overall system voltage may be appropriately dipping down due to the load of the tests being performed.

    If the camera sees 11.5 and the car starts a purge valve test *boop* maybe it's down to 11.4 for a second, the camera calls it a night, the test finishes and the voltage bounces back up afterwards.

    ...but the better answer is that 8 years is a great run for one of those 12v batteries. You got your money's worth, now it's time for a new one.
     
    #7 Leadfoot J. McCoalroller, Apr 26, 2023
  8. rhkcommander

    rhkcommander New Member

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    Yep, any load will drop it. You'll often hear one of the pumps humming away.

    I'm still on my original from 2012, but I got a new one to replace it anyway when I do the hybrid battery too.
     
    #8 rhkcommander, Apr 26, 2023
  9. douglasjre

    douglasjre Senior Member

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    #9 douglasjre, Apr 26, 2023
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