Getting lower gas mileage since "bad cells" replaced

Discussion in 'Gen 2 Prius Main Forum' started by cinsolidarity, Feb 28, 2019.

  1. cinsolidarity

    cinsolidarity New Member

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    Hi all.

    I recently took my 2006 Prius into the shop to fix a battery issue. This is a car I purchase about 6 months ago, assuming it was in decent shape. 158k miles on it.

    I paid $300 for basic reconditioning and that 300 included swapping out up to 2 cells if they're bad. The mechanic told me it was the worst battery he had seen in a long time and that I should try and sell it soon before it really begins to fall apart.

    He said he went ahead and swapped out 6 of the bad cells since they were so bad. I was getting an average of 54 mpg before he worked on it. Now I'm getting 48 mpg. Should I be suspicious that he actually took decent cells and swapped them for worse ones? Is there any reasonable/legitimate reason why I lost an average of 6 mpg after he did the work on it and swapped 6 supposedly bad cells?

    Thank you for your help
     
  2. fotomoto

    fotomoto Senior Member

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    Two things; replace the battery ASAP; preferably with new if you want the car to run right for a long time. Second; during the last 6 months the weather has changed. Heating the interior requires energy and in a prius all energy comes from gasoline. Combine that with a battery that's getting weaker and mpg's are going south.

    GOOD LUCK!
     
    #2 fotomoto, Feb 28, 2019
    Last edited: Feb 28, 2019
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  3. SFO

    SFO Senior Member

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    What codes were thrown that required taking it into a shop, you mentioned having a battery issue?
    That is still above the national fleet average, many don't get near that. How many tanks of gas have you used since servicing?
    Guess anything is possible, though unlikely. Was your battery untouched, or had the prior owner swapped modules in the past?

    Did you take it into Steve's shop - http://phoenixhybridbatteries.com/ ??
    Pretty sure there are many, and what @fotomoto said above makes the most sense, or it could be winter gas formulation, or the mechanic disconnected the 12v which reset the MPG, or the tires need air, or you have a battery that is actually on its last legs and could fail during the next heat storm or big hill climb.

    Keep the battery cool during the summer or when temps go over 70F, and I bet you get a bunch of extra miles out of your existing pack.
     
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  4. Skibob

    Skibob Senior Member

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