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Constantly fully charged

Discussion in 'Gen 2 Prius Technical Discussion' started by gumption, Jan 5, 2011.

  1. gumption

    gumption New Member

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    I have a 2007 Prius that, for the last 2 days, has remained at full charge through normal, flat-level highway driving. With typical driving, I expect to see the charge at half, or 1 bar above half. Anyone have an idea why I would be carrying a full-charge at all times?

    Related: my MPG has dropped from a typical 52-55 to around 47.

    Any thoughts?
     
  2. qbee42

    qbee42 My other car is a boat

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    How is the outside temperature? Cold weather can do that.

    Tom
     
  3. gumption

    gumption New Member

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    Hi Tom-

    Thank you for your reply.

    It been colder here than normal (it's winter), but not COLD. I live in Los Angeles, so cold here is 40-50F.

    Update on behavior: it seems that the full-charge issue is intermittent. The car started behaving normally during my drive to work. When I left work, the car was still acting normal. Then at some point while driving, the car started carrying a full charge (and continued to charge).

    Could a relay or sensor or something like that be at fault? I hope to not have to replace a computer!
     
  4. uart

    uart Senior Member

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    Hi Gumption. I cant find the post but I seem to remember that another member here had exactly the same problem a while back and the dealer couldn't figure it out or offer any help.

    Eventually the guy just tried disconnecting the 12V battery for an half an hour or something and then reconnecting it (effectively re-booting all the ECU's). It totally fixed it!
     
  5. GrumpyCabbie

    GrumpyCabbie Senior Member

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    What mileage are you at?
    Do you carry dogs?
    Is anything blocking the rear battery vent on the back seat?
     
  6. ursle

    ursle Gas miser

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    I like the re-boot idea, it's a digital device and re-booting forces all the electric gremlins to ground;)
    I wonder how old your 12v battery is, if it's weak the engine is constantly running to charge(drop in mileage) it and the traction battery will also always be charging or charged.
     
  7. MikeyC

    MikeyC Junior Member

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    I am also looking at a 07 Prius with 62k on it. The previous owner did car dogs as evident by the few dog hairs I found. Grumpy Cabbie what are you getting at?
    Were is the rear battery vent?

    I drove it today and noticedthat it was in the Blue range and only once did it get into the green (1 bar). ANd when it did it was a short time before it went back to blue... Outside temp was about 29-35F and the Heater was run for a short time.


    Is this a prerequisite to Battery problems?


    Mike
     
  8. GrumpyCabbie

    GrumpyCabbie Senior Member

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    There have been previous posts on here about owners suffering with the HV battery fan clogging up with dog hairs, causing it to not be effective which allows the HV battery to overheat (and also reducing its life!). There are some threads which give instruction on how to clean the HV fan - worth considering if dogs had been carried in the past.

    There is a vent hole on one side of the rear seat which is where the HV battery fan sucks air from. If it is covered by a passenger or dog etc then the battery can overheat and cause the full charge issue.

    Maybe I'm clutching at straws?
     
    1 person likes this.
  9. Rokeby

    Rokeby Member

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  10. Hal W

    Hal W New Member

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    Our the fan could have stopped. By the way is there a warning on the dash if this happens? H
     
  11. GrumpyCabbie

    GrumpyCabbie Senior Member

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    The fan is mostly whisper quiet when running but on hot days you will hear it as it can be quite loud. I'm not sure whether a warning light comes on if it fails though it is quite probable. Thing with the dog fur is that it doesn't stop the fan at first but just completely clogs it up and reduces its effectiveness. Because it's still running (though badly) the car still thinks all is ok (when it isn't).

    Check out the above link and see if it could assist.