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Help... I left my interior lights on!

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Misty fog, Nov 5, 2012.

  1. Misty fog

    Misty fog Junior Member

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    Left it on overnight, around 10 hours. Did I just screw up my traction battery? When I started the car again I saw 3 bars. Then the engine started running, I left it idle to run awhile. After a couple minutes it stopped, then after a couple of minutes the engine ran again... this repeated twice and then the SOC was almost at 8-9 bars!
     
    #1 Misty fog, Nov 5, 2012
  2. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    First the good news, you did no damage to the traction battery, it is completely disconnected when the car is not READY.

    Once you start the car, it will begin recharging the 12 volt battery, which has been powering the inside lights.
     
    #2 JimboPalmer, Nov 5, 2012
    Misty fog likes this.
  3. etobia

    etobia Member

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    You have basically reduced the battery strength and the gas engine is recharging it. Your mileage will reduce because of this, but as you state, the bars return to 8-9, so the engne has done it's job. Question: Have you returned the overhead light function to power off? :) No, i don't think you screwed up your traction battery......you merely restored it.
     
    #3 etobia, Nov 5, 2012
  4. sooperedd

    sooperedd Junior Member

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    Left mine on the first night after buying it. Didn't harm anything. Your Prius has a 12v AGM battery that can be drained much deeper than a typical Lead Acid. Don't even worry about it.
     
    #4 sooperedd, Nov 5, 2012
  5. Misty fog

    Misty fog Junior Member

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    OK, have been pretty careful about taking care of my Prius that I got quite upset about this incident. Feel much better now knowing no harm's done, thanks!
     
    #5 Misty fog, Nov 6, 2012
  6. lopgok

    lopgok Member

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    If you use led interior lights, the power drain will be about 5 times less...
    They are dirt cheap, and brighter than the lightbulbs and should never need to be replaced.
     
    #6 lopgok, Nov 8, 2012
  7. Mendel Leisk

    Mendel Leisk Senior Member

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    Your 12 Volt battery has taken a hit. You were lucky: an interior light left on overnight can kill a battery, unfortunately. Or put it near-dead. Don't just rely on assurances, see for yourself:

    Get a half-decent ($30~40 range) digital multimeter, and check the voltage to get a more complete picture of what your battery's health is. If it's 100% you'll get a reading around 12.7 volts or higher. Under 12.6 and it's likely taken some damage.

    You can do the voltage check under the hood, at the jumper location. It's in the underhood fuse box, check in the manual. Red lead to the jumper terminal, then black lead to a bare metal bolt or bracket on the car body or engine.

    An "intelligent" charger is worthwhile, for events like this, and just for periodic maintenance. My pref. is CTEK 3300, but it's kind of pricey, there are lots of choices. It will likely take an overnight charging session. The CTEK has indicator lights to indicate when it's still charging (amber), and when it's satisfied the battery is fine and fully charged (green).

    Another item to consider is a portable jump starter, for emergency use with dead battery.

    The hybrids tend to have diminutive 12 volt batteries, and an inadvertant light left on can kill them. Cheap insurance is to turn completely off as many of the "convenience" lights as you can, if you're ok with that.
     
    #7 Mendel Leisk, Nov 10, 2012
  8. Misty fog

    Misty fog Junior Member

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    I only left one side of the front interior light on overnight, and it seems everything is back to normal after the incident. No MPG hit or any malfunctions. Going to monitor the situation for awhile, probably get the service center to look at it once its time for the next checkup - not too good with self maintenance!

    Now, this might not be related, but yesterday I got the refuel alert (down to 1 bar). After driving for about 10km or so, I suddenly realized that the distance to empty is now zero! Fortunately the SOC was quite high, more than enough for me to make it to the gas station. I put in around 40.1 litres. I usually pumped at around 38.5 litres, was I really running on empty? Any chance the late refuel alert might be related to the battery drain on my 12v battery last week?
     
    #8 Misty fog, Nov 12, 2012
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