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Battery recal everytime SoC goes green?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by josh2008, Nov 20, 2010.

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  1. josh2008

    josh2008 Active Member

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    Hi all, I need your help.

    I'm not exactly certain how to explain this but I will certainly try. My fiance (member here MandiRocker) has an 05 Prius with 83K on the clock that is exhibiting some odd state of charge behavior that is continually getting worse. Any time the battery reaches a SoC level of greater then 62% or so (high 6 bars-8 bars) shortly there after SoC will starting bottoming out (as verified on ScanGauge) regardless of driving conditions to 2 bars (40%). You can be in glide, driving with the engine on (even with charging occuring and SoC will drop), this will even occur during regen. Once SoC drops to 40% the engine will kick on and charge the battery back to 4 bars (~51%) and that's it. Never higher. I've done some research and this seems to be consistent with a HV batt recalibration situation. This would be fine however except this is becoming a more common (every time) occurance. You use to be able to go to green Soc and it would slowly bleed back off to 6. If you hit green on a trip, drop to 4-6 bars, park car, when you leave for next trip it will drop right away to 2 (even if going downhill during stage 1). It now does the Soc crash every single time, the battery during normally driving doesn't ever seem to go above 4 bars now except with extended periods of highway driving and even then it seems to struggle to maintain 5-6 bars. This car has not always behaved this way and we're growing concerned that this may be early signs of HV batt failure. Since the car is still under HV batt warranty I wouldn't normally be concerned but she will be returning back to college in a few months and will be commuting 120 miles round trip in a day. I would like to try and get this taken care of before she gets stranded going to/coming back from school and or before warranty is out. I had her call the 1-800 number and get a case number. As my sig says I am a tech for Toyota, the veh has no codes but this is very abnormal SoC behavior. I've talked to the higher ups at my dealership and "cannot replace without failure DTC's". I apologize for the long post. Any insight/advice anything at all would be appreciated from you guys. Thanks as always. :)
     
    #1 josh2008, Nov 20, 2010
  2. andyprius

    andyprius Senior Member

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    As a Tech for Toyota you obviously know that there is nothing worse than trying to duplicate a malfunction. Since Toyota will only accept DTCs as proof of of HV Bat failure you must be able to think of someway to contribute There must be some natural way to stress the HV Bat. ( and legal ).
     
    #2 andyprius, Nov 20, 2010
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hi Josh,

    Thanks for sharing this story. One possibility would be for you to purchase and install a battery from a newer model year 2G that had been totalled. That might cost $600 or so, but incurring that cost might be better than worrying that your SO's vehicle will fail at some point during her 60 mile commute.

    Or, you could induce an early battery failure, and I imagine that you could figure out a way to make that happen if you really wanted to.
     
    #3 Patrick Wong, Nov 20, 2010
  4. josh2008

    josh2008 Active Member

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    Only other way to get replaced under warranty is approval from our FTS, I am looking into this.
    Patrick, I have been considering putting in a used pack and have been looking. Do you hace a reccomended source? Trust me, I've been thinking.;)
     
    #4 josh2008, Nov 20, 2010
  5. Patrick Wong

    Patrick Wong DIY Enthusiast

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    1. I don't have a recommended source, but eBay Motors has numerous 2G traction batteries for sale. Here is one example, supposedly from a 2007 with 30K miles, for a $400 Buy It Now price:
    04 05 06 07 08 09 PRIUS BATTERY HYBRID BATTERY PKG - eBay (item 370447918608 end time Dec-19-10 12:06:36 PST)

    If the battery is really as described, that sounds like a good deal to me.

    2. I'm wondering whether it would be helpful to disconnect the 12V battery negative terminal for a while, just to let the various ECUs power down and then have a fresh reboot when you reconnect the battery. Maybe that would help the SOC problem that your SO's car has?

    3. For fun, check the calibration levels of the engine and hybrid vehicle ECUs and download the latest versions relevant to the 2005 model year.

    4. To exercise the traction battery: Prius in READY, gear selector in N with gasoline engine off, AC set to MAX COLD so the compressor is running: traction battery SOC will drain down pretty fast and you can get it down to one red bar or no bars. Then shift to P, force charge back up to 8 green bars, rinse & repeat...
     
    #5 Patrick Wong, Nov 20, 2010
    1 person likes this.
  6. spinkao

    spinkao New Member

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    Hi Josh,
    I assume that as Toyota technitian you know better than me, but what about the 12V battery? How old it is, and did you test its condition? It is known that dying 12V battery can cause some rather odd behaviour, although I am far from stating that it is indeed the cause, or even a likely possibility, of your problems.

    If I were you, I would check and perhaps even replace the 12V battery as a precaution (if it is more than, say, two years old), and in case it does not help, I would perform some tests on the traction battery. For example, I would force-charge it to 8 greens and try how far would the vehicle go at a steady slow pace in EV mode. If it is less than say half a mile, I would probably start to worry. I would also inspect the HV battery visually, checking especially the contacts for any signs of corrosion. I would also check the voltage of individual cells and look for weak ones, preferably under some reasonable load (with the vehicle powered on and engine stopped). This should tell you something about the condition of your HV battery.

    Also, does the HV battery lose charge when the vehicle is parked and powered off overnight? This would also be an indicator of possible impending failure.
     
    #6 spinkao, Nov 20, 2010
  7. josh2008

    josh2008 Active Member

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    May just have to try this, wonder how many cycles it would take at this point.
     
    #7 josh2008, Nov 20, 2010
  8. josh2008

    josh2008 Active Member

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    My apologies for not properly quoting that, Pat, some of my replies are in the quote box. Thanks!
     
    #8 josh2008, Nov 20, 2010
  9. josh2008

    josh2008 Active Member

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    I did test the 12v and it does check fine, in fact just as good as the one in my 2010. When the battery goes green and if I enter glide state then, not even using battery power for ev propulsion the battery will go from green to the point of kucking the engine on at bottom of two bars in exactly .5 mile. On one occasion, few weeks ago she did park at work with 6 bars and when she went to leave it was down to 3, car had been off the whole time.
     
    #9 josh2008, Nov 20, 2010
  10. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hi Josh,

    After further thought, my guess is that the symptoms are more likely associated with the traction battery ECU acting weird, than the traction battery itself. I suggest that you try powering down the 12V bus, to see if that results in an improvement in the symptoms. Good luck.
     
    #10 Patrick Wong, Nov 20, 2010
  11. josh2008

    josh2008 Active Member

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    Where should I have SoC at before disconnecting 12v?
     
    #11 josh2008, Nov 20, 2010
  12. Patrick Wong

    Patrick Wong DIY Enthusiast

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    If you are referring to the traction battery SOC, it doesn't really matter. After you return power to the 12V bus and make the Prius READY, the traction battery ECU will develop a new estimate of where it thinks the traction battery SOC is.
     
    #12 Patrick Wong, Nov 21, 2010
  13. uart

    uart Senior Member

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    #13 uart, Nov 21, 2010
  14. josh2008

    josh2008 Active Member

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    Just hooked 12v back up after ~1hr40min of being disconnected. Going to go for a drive soon. One odd thing tho, parked with 2 pips on the fuel gauge, it's now flashing and saying add fuel and ScanGauge shows 12.5% fuel remaining. I even turned car off and back on a few times, still flashing. Odd.
     
    #14 josh2008, Nov 21, 2010
  15. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hi Josh,

    After you reconnect power to the 12V bus, it takes a while for the fuel gauge to decide how much fuel is in the tank. In the meantime the gauge will flash one bar, that is normal.
     
    #15 Patrick Wong, Nov 21, 2010
  16. josh2008

    josh2008 Active Member

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    The fuel gauge did during the test drive return to normal operation. Ok, just got back from test drive. Results - absolutely no change in hv batt behavior. Once the SoC hit green range and the SoC starting crashing it was flat in .4 miles. It then charged back to 6 bars (which is odd) and then began dropping again. After that it hung out at its usual 4 bars. What are your thoughts Patrick? I thoroughly appreciate all your help/insight on this.
     
    #16 josh2008, Nov 21, 2010
  17. caffeinekid

    caffeinekid Duct Tape Extraordinaire

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    As a general rule, if any given machine has computer modules and logical controls, it will need a "battery pull" every now and then. It should be one of the first steps taken upon unusual behaviors...coded or otherwise. I couldn't honestly count how many devices I have repaired with a proper reset and/or harness disconnect/reconnect...everything from cell phones to iPods to automobiles.
     
    #17 caffeinekid, Nov 21, 2010
  18. josh2008

    josh2008 Active Member

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    Have had to do this to my Droid, know what you mean. :)
     
    #18 josh2008, Nov 21, 2010
  19. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hi Josh,

    What is "flat": Does that mean no bars on the SOC gauge?
     
    #19 Patrick Wong, Nov 21, 2010
  20. josh2008

    josh2008 Active Member

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    Sorry for vague description, "flat" is bottom of 2 bars, ~40%, where it bumps the engine on to recharge.
     
    #20 josh2008, Nov 21, 2010
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