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Clock off and auto-window up/down not working w/o losing 12V

Discussion in 'Gen 2 Prius Technical Discussion' started by roflwaffle, Aug 14, 2012.

  1. roflwaffle

    roflwaffle Member

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    Anyone have any ideas about this? All my radio presets are still there, so it probably wasn't lack of power from the aux battery. What else could cause the clock to reset and the DS window to forget the auto up/down settings?
     
    #1 roflwaffle, Aug 14, 2012
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    It is most likely that your 12V battery is close to dead. The radio station memory may tolerate a brief loss of power.
     
    #2 Patrick Wong, Aug 14, 2012
  3. roflwaffle

    roflwaffle Member

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    As of 3 hours after being operated it's at 12.3V. It could be on it's last legs, but it seems odd to me that the window/clock would be reset but not the stations. I ran the battery down after having the headlights/radio on for about twenty minutes recently, is it possible that having the interior lights on for an hour could have done something similar?
     
    #3 roflwaffle, Aug 14, 2012
  4. Patrick Wong

    Patrick Wong DIY Enthusiast

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    It certainly is possible if the 12V battery has limited capacity, which appears to be the case given the circumstances that you have related.
     
    #4 Patrick Wong, Aug 14, 2012
  5. Tideland Prius

    Tideland Prius Moderator of the North
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    It's possible though the dome lights have a 20 min timer and a 5W map light shouldn't drain it in 1 hour (I've left the hatch ajar overnight and the car started up in the morning). I've also left the map light on for several hours during the day (too bright, couldn't tell it was on when I locked the car).
     
    #5 Tideland Prius, Aug 15, 2012
  6. roflwaffle

    roflwaffle Member

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    After sitting overnight the battery was at 12.1V and sagged to 11.8V during startup. I imagine it could be at something like 25% of capacity, which would be a whopping 60Wh in real world (not C/20) use. Maybe I can replace it with a more durable chemistry... :)

    Edit - I just had the clock jump to some random number again, and I noticed the car didn't shut down after one button press, so they may be related. The most I can get battery voltage to drop to by getting on the brake pedal while the vehicle is off so the booster activates seems to be 11.1V, but there could be some sort of intermittent problem with a single cell that causes voltage to drop well below that.

    Edit 2 - Found the problem. I left the positive battery cable loose, user error ftw.
     
    #6 roflwaffle, Aug 16, 2012
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