It might be time for a new traction battery....

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by nedim, Feb 15, 2015.

  1. nedim

    nedim Junior Member

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    Hey everybody. Would like to get some opinions on my case.

    I left my house this afternoon and headed to the car wash.. My battery about %60. Today was sunny and there was a line of 7-8 cars for the wash. It took me maybe 4-5 minutes to get in the wash and that was all in EV mode. In the tunnel I get a message that says " Low traction battery please put car in park"( it was something like that) . So after that the engine charged the battery to 60% and I have driven 160 miles city driving and the engine never went off.. Just came back home turned the car off and it starts immediately with the engine running...
    btw NO DTC's !! if someone can tell me how can I check with Techstream battery health that with be great.

    I remember other member here replaced his battery like a month ago. He said that it discharges and charges very quick.. I saw that symptom too..

    I know 200+ miles are a lot but I was hopping that the battery will go bad module by module....seems like they are all bad..

    I did a test a month ago on Max V - Min V but the biggest number I saw 0.7

    So I guess it is time for a new used battery, but before that just wanted to hear some thoughts.

    Thanks
     
  2. bisco

    bisco cookie crumbler

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    oh boy.:( how did you test, never heard of all the modules going bad.
     
  3. kc410

    kc410 Active Member

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    It sounds like one (or more) of the 14 batt module pairs has a weak cell. When the Vmax-Vmin voltage gets to ~0.7V is when the battery becomes a a major problem to deal with driving. What happens is when the battery gets low the weakest cell starts to drop in voltage very fast. What I noticed on my battery was as long as Vmax-Vmin never dropped below 0.7V the ICE would operate normally. When Vmax-Vmin does drop below ~0.7V it would set a code P0A90 & would force the ICE to run continuously when the Prius was in Ready mode. In Torque I could see the trouble code under "Fault Codes". I could "Reset" the fault codes, which would clear this code & immediately the ICE would shut off if I was sitting/parked & in "Ready" mode.
    Before the battery got really bad it would set a "Pending Trouble Code P0A90" that would only show up when I manually asked Torque to check for trouble codes. I think this "Pending Trouble Code P0A90" gets set when Vmax-Vmin gets below ~0.7V, but only for a brief time.
    The "Pending Trouble Code" will not display any faults on the Prius dash.
    When it sets the hard fault P0A90, that will light up the dash ! & check hybrid iirc.

    Find out where in Techstream to check & reset trouble codes. Either one of these codes will reset (clear) when you "reset trouble codes" & the Prius will drive normally until Vmax-Vmin gets to ~0.7V or more.

    Torque is easy for me to use any time I am driving. I remember one time when I got into some road construction & was forced to run the battery low. The dash lights up & the ICE runs continuously, but the Prius drives OK. I just got to an area I could get out of traffic & put the Prius in Park (still Ready). The ICE continues to run as I get Torque connected. Once I check trouble codes & see it is the P0A90 I reset the trouble codes, the engine immediately stops as I put the Prius in Drive & continue on my way.
     
  4. IMkenNY

    IMkenNY Im just being nosy

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    Other Prius members have had problems with automatic car washes draining the HV traction battery and not only getting the warning message but also have the car shut down when the warning goes unheeded .This was a result of having to leave the vehicle in neutral which disabled the ICE from recharging the battery.

    The software is set to shut down the Prius before the traction battery is completely depleted.

    If your problem persist, a traction battery grid charger may be the answer for your battery.
     
  5. Christian_cool

    Christian_cool Junior Member

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    Sounds like your battery is bad.. How many miles/kilometer on her before you got this battery issue?
     
  6. jdcollins5

    jdcollins5 Senior Member

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    +1 Above

    Chances are there is nothing wrong with your battery. If it were the car it would be throwing DTC's and you would not be able to drive the car. You pulled down the HV Battery driving in EV and then putting it in Neutral to go through the car wash. A lot of members have reported this problem.

    If the difference between Max-Min is greater that 0.3V for a time delay it will be generating a DTC and stopping the car.

    Continue to drive it and see if the battery gets fully charged and the engine turns off.
     
  7. kc410

    kc410 Active Member

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    Vmax-Vmin of less than 0.7V will not set a trouble code. When Vmax-Vmin goes over ~0.7V it will set a trouble code & cause the ICE to run continuously. The Prius is still drivable, even for long distances if necessary. I have encountered this situation a few times when my traction battery was failing.
     
  8. wjtracy

    wjtracy Senior Member

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    By my count we have only had one Gen3 HV battery replaced here on PriusChat in the USA, excepting some taxis in Europe.
     
  9. HaroldW

    HaroldW Active Member

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    Go to the cleanmpg forum. Com and check out the thead $7.00 repair of traction pack. Very interesting. Clean-up the .corrosion saved the owner $4400. Dollars. Hal
     
  10. nedim

    nedim Junior Member

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    Thanks for the info. I started the car this morning, it did its normal warming and engine shut off... Where exactly in Torque you can see pending codes ? I did not see any codes in ScanGauge, Torque or Techstream ....
    Doing the test where you engage the parking break and put the car in reverse shows me Vmin-Vmax = 0.1 ...I can see that number change only if I am driving...

    As I remember you did change the whole battery, right ? Why didn't you consider replace only a module ? And here comes my next question... How can you tell which module is bad ????

    One other thing...What I noticed on ScanGauge is that when I drive the car in EV mode or stay parked with AC on SOC from ~70% goes slow down to 50%.. When the car is under 50% it just deploys the battery to 35% in maybe less than a minute( not always tough, but most of the time) For example yesterday, till I got in to the tunnel the car was probably at 45% and then in the middle of the tunnel it was 25% when I saw that message...( NO AC ON)

    I am thinking of a Grid charger option, but don't want to invest $500 for maybe 2 months fix ?
    I noticed the fast drop/charge maybe at 200k miles and now it happened at 204k miles
    I am pretty sure I am the only one in this forum with that many miles.

    I tried searching for it, nothing ... Can you send me a link ?
    Thanks
     
  11. Mendel Leisk

    Mendel Leisk Senior Member

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    'Nother thing, steer clear of car washes, at least that type. The Prius transaxle just doesn't work well with that setup.
     
  12. jdcollins5

    jdcollins5 Senior Member

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    The Repair Manual says greater than 0.3v for a set time delay will set a DTC. Where are you getting your information?
     
  13. Former Member 68813

    Former Member 68813 Senior Member

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  14. kc410

    kc410 Active Member

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    From 6 months of monitoring the Prius via Torque while watching the traction battery die.
    I drive the vehicle on a daily basis. I always have a BT adapter plugged in. Cell has Torque Pro.
    I mostly monitored the 14 battery module pairs & monitored the Vmax_block & Vmin_block, along with SOC, temp readings, fan speeds etc.
    When I was curious about what or why of anything I would look & see what was really going on.
     
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  15. kc410

    kc410 Active Member

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    Just to give ppl an idea of what I monitor via Torque Pro, I have two screens of information - one screen of 24 & another of 23.
    main page: all 14 battery module (pair) voltages, Traction Battery voltage, Traction Battery Current, Vmax, Vmin, Block # max, Block # min, SoC, Fan Mode, Aux Battery, Vmax-Vmin
    Second page: all 14 internal resistances, Fan Mode, TB intake, TB1, TB2, TB3, Aux Battery Voltage, Aux batt temp, plus a couple more.
     
  16. jdcollins5

    jdcollins5 Senior Member

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    I have something very similar using Engine Link on my iPad. I have seen Vmax-Vmin bump 0.3V but have never seen anything higher.
     
  17. kc410

    kc410 Active Member

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    Lets see if I can answer these one at a time...

    Thanks for the info. I started the car this morning, it did its normal warming and engine shut off... Where exactly in Torque you can see pending codes ?
    ANSWER: a pending code will show up the same place as a fault code. In Torque its under "Fault Codes". after it checks for faults on its display page a pending code will "Pending Code" in front of it. A pending code never shows up on the Prius dash (at least it never did for me).

    I did not see any codes in ScanGauge, Torque or Techstream ....
    ANSWER: like above - in Torque hit "Fault Codes" & let it run - takes ~ 1 minute & it will display a page - any codes will be shown there.

    Doing the test where you engage the parking break and put the car in reverse shows me Vmin-Vmax = 0.1 ...I can see that number change only if I am driving...
    ANSWER: I have never done the "parking brake test".
    ANSWER: This is going to be a longer answer (there is no short answer) - The Prius will only allow the battery to operate in the range of 40-80% SoC (State of Charge). The Prius will try very hard to keep the battery at 60% SoC. At 60% SoC the module pairs in my failing traction battery would still be very close in voltage, sometimes within 0.1V across all 14 pairs. BUT, below 60% SoC the voltage difference became very pronounced & the module pair with the weak cell would fall off very fast. Say at 55% SoC the battery might show 0.7V difference between Vmax & Vmin & below 55% SoC things got much worse. Here is the unexpected part - Going above 60% SoC was just as bad. Slowing down from hi speed to a stop would put a substantial charge into the battery. The module pair with the weak cell would soar in voltage compared to the other 13 module pairs. This has at times caused the P0A90 fault for me.

    As I remember you did change the whole battery, right ?
    ANSWER: yes
    Why didn't you consider replace only a module ?
    ANSWER: I did consider that. I considered it enough to purchase two HiTec x4 80 chargers & one HiTec 30A power box to run them (I have another HD 12V supply to run one of the HiTec chargers). With that I can do 8 battery modules at the same time. The problem is, even at the best the Prius will be out-of-service for 3-4 days at a minimum.
    Then I found a whole traction battery - then had to build a new charger/discharger to cycle the whole pack.

    And here comes my next question...
    How can you tell which module is bad ????
    ANSWER: by monitoring the voltages of the 14 battery module pairs. As the battery discharges most of the 14 voltages will track each other. Most likely you will see one of the module voltages dropping quite a bit below the other voltages. This module pair will point to two battery modules, either of which could contain the weak cell. Another way to find which module pair is weak is by monitoring the Torque pids "Block# min" & "Block# max". During discharge (<60% SoC) the "Block# min" will be the block with the weak cell. During charge (>60% SoC) the "Block# max" will (probably) be the block with the weak cell. Now you know it is one of two adjacent battery modules. You need to use a voltmeter to determine which module has the bad cell. I do not suggest doing this BUT in theory you could pull the cover on the traction battery while it is installed in the vehicle & run down the traction battery & then measure the modules. All 28 of the modules will track each other very well if they are good. The ones that drop the most contain failing cell(s)


    One other thing...What I noticed on ScanGauge is that when I drive the car in EV mode or stay parked with AC on SOC from ~70% goes slow down to 50%.. When the car is under 50% it just deploys the battery to 35% in maybe less than a minute( not always tough, but most of the time) For example yesterday, till I got in to the tunnel the car was probably at 45% and then in the middle of the tunnel it was 25% when I saw that message...( NO AC ON)
    ANSWER: I do not have a ScanGauge. The SoC that appears on the dash of the Prius is NOT an accurate gauge when the traction battery is failing. With a _good_ traction battery installed, the dash gauge is fairly accurate, but very slow to respond. Note I have stated a few times before - the Prius tries _very_ hard to keep the battery at 60% SoC. With a failing traction battery going below 60%SoC is like falling off a cliff. There is just no more capacity in the failed cell when it gets somewhat discharged.

    What I tried to do to keep using my traction battery for another few weeks/month(s) was to avoid getting the battery out of its 60% SoC area. If I was stuck in traffic or had to sit for any length of time I would keep the Prius in "D" with my foot on the brake & press on the accelerator to force charge the battery. I would try to get the battery back to 60-62% SoC then let the ICE shut down.
    Also I would try not to use the AC if stuck in traffic as it pulls the batt. down fast (with a weak traction battery).
    If I found myself having to slow down from speed lots, to keep the battery from getting much over 60% SoC I would turn the AC on high (very cold) to use up the regen. amp-hours that got put in the batt. Remember the Prius will set a code during regen braking also if one cell gets fully charged & its voltage soars.

    Gosh, I'm tired now! Happy reading
     
    #17 kc410, Feb 15, 2015
    Last edited: Feb 17, 2015
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  18. kc410

    kc410 Active Member

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    Well, that is what my battery was doing when I first started monitoring it.
    At anything around 60% SoC all the voltages would be within 0.1V.
    It was only when discharging below 60% SOC that one voltage would drift lower than the others.
    For me, the problem first came to my attention when I was watching "Blk#max" & Blk#min" together.
    I would often see 1 & 7.
    Block 1, being at the end will be the coolest.
    Blocks 1 & 14 are the end sets of modules & blocks 7 & 8 are the middle (hottest) sets of modules.
    Block 7 had a cell that continued to go downhill, slowly for the longest time, then it started getting bad fast.
    There is a good chance you will find the Blk#min to be the same every time the battery is much below 60% SoC.
    Still it is possible that the battery will not get any worse in 10 years - but good to keep an eye on it :)
     
  19. jdcollins5

    jdcollins5 Senior Member

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    I see Block 6 the most at Block # min although it is constantly changing. I have been watching this for some time but have not seen any appreciable difference. I will keep monitoring it closely.

    Thanks for your insight above.
     
  20. kc410

    kc410 Active Member

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    With Vmax-Vmin just touching 0.3V at times, it is possible that there is no real problem at all. Each of the block voltage measurements takes time & are done sequentially so there can be voltage variations between the blocks as the readings are not made at the exact same time.
    Ideally both Blk#max & Blk#min would jump around at random indicating all 14 blocks are equally matched. In reality block #1 (or 14) is probably going to be the best because it has the best cooling. If Blk#min jumps around, even when the battery is discharging at say 50%, then things are fine. Then again, if you start seeing the same Blk#min when the battery is discharging at say 50% or lower, it definitely is somewhat weaker than the rest.
     
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