what to do after jumpstart

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Ynprius, Mar 4, 2019.

  1. Ynprius

    Ynprius New Member

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    My Prius didn't start this morning. I'm pretty sure that the issue is a dead battery. Last night, at around 1am, I noticed my headlights had somehow turned on. This was really strange because they were clearly off when I got out of the car and walked through my driveway. When I went to inspect the car (was someone breaking in?!), I noticed I couldn't unlock the doors. I tried and tried and tried to unlock the doors with my remote key (no mechanical key, unfortunately) for about 10 minutes but I finally got it opened. Then I turned off the headlights and tried starting the car but it didn't power on. Not sure what happened but the headlights somehow turned on while the car was off and drained the battery. Since it was 1am, I decided to wait till the morning to do anything, and of course, the car wouldn't start in the morning either. So now I'm having roadside assistance come jumpstart my car. What should I do after that? Can I drive to work just fine? I read online you should leave your car on ready for ~8 hours before you drive it. Is that true? Do I have to take it to the dealership or a mechanic after this? Or can I do without that?
     
  2. WilDavis

    WilDavis Senior Member

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    When you first get into the car, is the dome-light at normal brightness, or is it dimmer than usual?

    I don't know how experienced you are re. electronics. Have you access to, and do you know how to use a digital multi-meter? If all else fails, you here is a way of checking the 12V AuxBattery which doesn't require any equipment:

    DO-IT-YOURSELF TEST PROCEDURE (thanks to jdenenberg):
    - Without brake pedal, press the Power button once and release to enter ACC mode
    - Press and hold the MFD Info button, then turn the headlights on and off three times to enter Maintenance mode; release Info button
    - Press “Menu” (on screen)
    - Press “Display Check”
    - Press “Vehicle Signal Check” - the battery voltage is shown and should be about 12.4 to 12.8 Volts (normal for an unloaded* battery)
    - Again without brake pedal, press Power button and release to put a current load on the battery - the voltage should stay above 12.0V (if less than 12.0V the battery is not well, or there is a fault or unusual load somewhere)
    - Press brake pedal and press Power button once to enter "Ready" mode - the battery is now charging at about 14V (if less than 13.6V or more than 14.4 there may be a problem with the charging circuit)
    - Turn car OFF to leave Maintenance mode

    * you can load the battery by turning on the headlights!

    Good luck! - hope this helps - Wil :)

     
    SFO likes this.
  3. SFO

    SFO Senior Member

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    Hopefully the roadside person knows how to jump start the vehicle correctly (from under the hood, instructions are in the owners manual) without blowing something up. Once the vehicle is running you can drive it again. If your 12v battery is old it may not take much of a charge and might need to be replaced (autozone, pepboys, dealer, etc).

    Can you safely let the vehicle charge itself in "Ready" and "P" at work for the day?

    How old is your existing battery?

    Now might be a good time to consider a new/used lock set for one of the doors.
     
    Raytheeagle likes this.
  4. Skibob

    Skibob Senior Member

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    There is a mechanical key located inside of your key fob. Do you not have that key? Was your headlight switch physicaly on?
     
  5. padroo

    padroo Senior Member

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    If it is the original 12 V. battery I would replace it and then go from there. You need to get friendly with your owners manual and lean a few 12V skills, they will pay off in the future.
     
    WilDavis likes this.
  6. Mendel Leisk

    Mendel Leisk Senior Member

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    I would get the battery tested first, to see if it's viable. You can do a rudimentary check of voltage with a digital multimeter, that'll get you started, but a more in-depth test with an electronic load tester is better, will report voltage and test the Cold Cranking Amps, which is a good barometer of the battery's "health" You can DIY this test with something like Solar BA5, or take it round to most automotive retailers selling batteries, likely test for free. Or dealership, for maybe $50. Maybe free if you're a regular.

    Next step, if it seems viable, would be to hook it up to a smart charger, 3~4 amp range. The kind that will do a full charge regimen, then taper off, trickle charge, if you want. CTEK 4.3 is an example. And see how it goes from there.

    All that said, you can also just go the charger route: the charger will not commence charging if the battery is toast, so can act as an assessor as well. And it if keeps running and running, never indicating complete, you know it's time for a new battery.

    And all that said, lol, if it's over 5~6 year old, it's time for a new battery in any event.
     
    padroo likes this.
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