Battery, MPG issue. Is my battery failing?

Discussion in 'Gen 2 Prius Technical Discussion' started by Morganp1, Oct 8, 2015.

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  1. Morganp1

    Morganp1 New Member

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    I bought a 2006 Prius in May and it now has around 120,500 miles on it. The past two weeks I've been getting increasingly worse MPG, starting at 42 and now dropping down to 32 avg. I usually get around 50 but I initially chalked it up to an increase of highway driving. Today I noticed that my battery level went down to one and then two lines and was purple, then a few minutes later went back up to five or so and was blue and then went to green again. It kind of seemed like it lost some power too. My average MPG says it is 32.

    Not sure if this is related, but last week when I filled the tank, it only took 7ish gallons, where it normally takes 9.5. The first line of the gas level, which typically takes about 100+ miles to go away went down after 25 and the tank was empty after 300 miles rather than my normal 500. But then when I refilled the tank yesterday and it took the full amount.

    Is there something wrong with my electric battery? What could be causing the poor MPG and low battery?
     
    #1 Morganp1, Oct 8, 2015
  2. greasemonkey007

    greasemonkey007 Active Member

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    A failing hybrid battery will cause the gas mileage to decrease, and your battery graph will go up and down quickly. If you don't have it already, I would suggest getting a mini VCI to help diagnose your problem. They're less than $50 on ebay or amazon. You can not only check and clear fault codes, but you can read battery voltages, and get a good idea of the health of your hybrid battery.
     
    #2 greasemonkey007, Oct 8, 2015
  3. Eclipse1701d

    Eclipse1701d Prius Enthusiast

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    42 to 32 is a big drop. Purchasing mini-vci would allow you to check the individual cells, in your hybrid battery, for problems. Of course, there are other things to check. Your 12 volt auxiliary battery may be failing. But, I don't think that your mpg would drop by 10. I could blast you with a complete list, but I would start with mini-vci and checking your 12 volt...
     
    #3 Eclipse1701d, Oct 8, 2015
  4. Aaron Vitolins

    Aaron Vitolins Senior Member

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    Sounds like the Hybrid battery is on the way out :( I don't see why, but for some reason over the time I've been on this sight, I've seen a lot of 2006 Prii with battery problems... We have two, the oldest just crossed 190,000 miles yesterday and 11 years old. It shows hardly any signs of battey issues! It stays at 6 blue bars almost all the time.
    My 2005 has 270,000 mile and is running great. I changed the battery at 239xxx miles due to an amazing deal on a 2008 battery. It did show slight signs of age before I replaced it, it would drop bars on the battery graph pretty quick if driven in the city, or using the AC.

    Maybe your battery has a bad cell or something. Has this car sat for long periods of time?
     
    #4 Aaron Vitolins, Oct 8, 2015
  5. JimN

    JimN Let the games begin!

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    If you are in a CARB state the battery could still be under warranty. If so, it may be worth a trip to the dealer to at least document the problem in case it fails just after the warranty expires.
     
    #5 JimN, Oct 8, 2015
  6. jeff652

    jeff652 Senior Member

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    This is a negative recalibration, and it is the first tangible sign of a degraded battery that is starting to fail. If you are covered under warranty and you can convince the dealer to replace the battery for you even though it has not "failed" yet, you should go that route. If not, you should consider reconditioning the pack with one of our Prolong Reconditioning Packages. If you treat the battery soon enough, you will most likely be able to recover the pack and enjoy a couple years or more of life extension from your current battery.
     
    #6 jeff652, Oct 12, 2015
  7. johnnyb588

    johnnyb588 Member

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    Not to thread-jack, but I'm looking into getting a mini-VCI, but everything I have found seems to require XP or some 32-bit version of Windows in order to work. That's something I don't have. Am I correct in my understanding that 32-bit Windows is the only way to go?
     
    #7 johnnyb588, Oct 13, 2015
  8. greasemonkey007

    greasemonkey007 Active Member

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    I've got mine on a new laptop with windows 8.1 (64 BIT system). But I had to have the vci installed on a virtual machine, so it thought it was on a 32 bit system. I turn my computer on and open the virtual machine, then go to techstream. I had my computer repair guy install it for me.
     
    #8 greasemonkey007, Oct 13, 2015
  9. y_one2002

    y_one2002 Junior Member

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    I ordered mine a week ago on ebay for 64bit version. Cost $40. Use price filter, u will find it.
     
    #9 y_one2002, Oct 13, 2015
  10. Sillywizard

    Sillywizard Junior Member

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    Is there a VCI or mini-VCI for Mac that will diagnose the condition of the HV-battery?
     
    #10 Sillywizard, Oct 14, 2015
  11. Eclipse1701d

    Eclipse1701d Prius Enthusiast

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    No Apple VCI... Not even an app for that...
     
    #11 Eclipse1701d, Oct 14, 2015
  12. dolj

    dolj Senior Member

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    No, but you can run it in a Win XP or Win 7 virtual machine in Bootcamp on your Mac.

    You could also use VMWare or Parallels.
     
    #12 dolj, Oct 16, 2015
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