Prius Gen II - Dying Traction Battery Question

Discussion in 'Gen 2 Prius Main Forum' started by Woodchuck, Jan 17, 2019.

  1. Woodchuck

    Woodchuck Junior Member

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    We've had our Gen II Prius since it was new and the traction battery is clearly starting to fail. While I have no CEL or anything, my mileage is down to 35-36 on average. My question is: Will the Prius leave me stranded if the battery fails while I am 200 miles from home? Or can I still limp home on the ICE alone? If I can limp home, can I sustain highway speed on the ICE alone?
     
  2. JC91006

    JC91006 Senior Member

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    There are many things that can leave you stranded 200 miles away, it's not only the HV battery that can do that. If you have that fear, you would have to take action and start replacing parts on your 12 year old car.

    But specifically about the question you asked, the HV usually will not just die, it most likely will have 1 failed cell and all the scary dash lights come on to scare you. Unless you know what those lights are for, you'll just have to risk driving it home (it "normally" won't just die). It may or may not be the battery when those lights come up.

    Have you checked the health on your 12v battery? Usually a mileage drop that big will be related to a 12v battery or low under inflated tires
     
    #2 JC91006, Jan 17, 2019
    Last edited: Jan 17, 2019
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  3. Skibob

    Skibob Senior Member

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    AAA with the 200 mile free tow is 119 a year 1-200 mile or 3-100 mile tows a year.
     
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  4. bisco

    bisco cookie crumbler

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    you can't limp home once the pack won't turn over the engine. it can get to the point where you're underpowered.
    not many stories here of people who were stranded due to a bad hybrid battery, but you can't go on forever. unless you're waiting for an inheritance, replace the bad cells, the whole pack or the car
     
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  5. Woodchuck

    Woodchuck Junior Member

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    Thanks All. I still have no Red Triangle of Death yet, but it sounds like it may be in my (and my Prius's battery) 's best interest to try and tackle this now, before more damage occurs. I have access to Techstream and I am good with the procedure to replace bad cells. I guess it might be time to tear into this little car on a weekend and see what I can do. I'll let you all know how it goes.
     
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  6. bisco

    bisco cookie crumbler

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    don't forget to balance!(y)
     
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  7. Woodchuck

    Woodchuck Junior Member

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    I have the Prolong Charger and Discharger, so will do!!!
     
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  8. bisco

    bisco cookie crumbler

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    have you been using it?
     
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  9. Woodchuck

    Woodchuck Junior Member

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    Yes, but as of late I keep seeing the mileage quickly creep down from 41 down to 35 or so in short order. Last year I conditioned the battery about 3x with progressively poorer results each time.
     
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  10. bisco

    bisco cookie crumbler

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    tech stream will tell you the condition of the cells. it could be that you have other problems
     
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  11. Raytheeagle

    Raytheeagle Senior Member

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    How long have you been reconditioning?
    Do you have the intelligent Discharger?
    Do you discharge down to 17 volts?
    How many reconditioning cycles have you done?
     
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  12. Woodchuck

    Woodchuck Junior Member

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    I bought the Prolong about 18 months ago and have used it 4 times. I do have the discharge unit. Each time I have followed the full set of instructions and discharged to 17v and then finally balanced the battery. Initially there was an improvement to about 42mpg, but now the Prolong system only has a minor effect. The result diminish from 41 mpg to 35mpg after a tank or two of fuel.


    iPhone ? Pro
     
  13. Raytheeagle

    Raytheeagle Senior Member

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    How long are your reconditioning sessions lasting?

    Do you do top end balancing between reconditioning sessions?

    Is each reconditioning session three cycles?

    While mpg is low, does the battery pack seem to not cycle?
     
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  14. Woodchuck

    Woodchuck Junior Member

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    It takes almost 4 days to complete the full cycle. I only do balancing when I charge it initially and then again after the last discharge (down to 17v). Yes, there are 3 sessions involved in the full process. On the last question: It seems to cycle, but the motor is clearly laboring more

    I plugged Techstream in and all of the cells seem to be reliably at about 15.5 volts. No codes. Maybe my Traction battery is fine and there is some other issue?


    iPhone ? Pro
     
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  15. Raytheeagle

    Raytheeagle Senior Member

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    So every 4 months you do a full 3 cycle reconditioning?

    No just top end balances in between the 3 cycle reconditioning sessions?

    How long do you hold at the top end after each discharge cycle before starting the next one?

    If you are ever interested, we have meet ups in the Bay Area and should be one soon:

    Possible Monthly install meets. Bay Area-Fremont
     
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  16. Woodchuck

    Woodchuck Junior Member

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    Correct. Correct. I just wait for it to top out during the middle discharge/charge and call it good. For the final one, I hold it for 6 hours for the balancing.

    Thanks for the link. I’ll try and make one, but I have 3 young kids so it’s hard to be sociable!!! Lol


    iPhone ? Pro
     
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  17. Raytheeagle

    Raytheeagle Senior Member

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    I’ve got a 7 and 6 year old, so I understand ;).

    I’d say let it top end balance a bit more and see if that improves ;).

    What condition is the ice in? Consume any oil?
     
  18. Prodigyplace

    Prodigyplace Senior Member

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    Also remember to wait after the final charge before driving. Otherwise you can kill the battery.
     
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  19. dolj

    dolj Senior Member

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    Or .... just use your discharger to take it back down to 222 V if you need to drive/switch on before 2 hours.

    My opinion is that unless you are in the final death throes of battery life, every 6 months (if my calculations are correct) is too frequent. As you have observed, you are getting little benefit from your subsequent charging sessions. Maybe only do full sessions annually.
     
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  20. JC91006

    JC91006 Senior Member

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    Or simply start the car and put it in neutral, that won't charge the battery. Put the AC in high until the SOC drops
     
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