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Gen II Prius Individual Battery Module Replacement

Discussion in 'Gen 2 Prius Technical Discussion' started by ryousideways, Apr 24, 2013.

  1. Phildo

    Phildo Active Member

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    What charger do you have that will discharge at 5A?
     
  2. tri4all

    tri4all Member

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    an older Dynamite Passport ultra charger. I also have two new chargers but only go up to 1-2 A max. it looks like the new version of the passport ultra also goes up to 5 A discharge

    what are your thoughts on the question I posted?
     
    #2402 tri4all, Oct 30, 2019
    Last edited: Oct 30, 2019
  3. Ed69

    Ed69 Junior Member

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    Reporting back to The Prius Collective to add data points on HV battery reconditioning.

    I used the Prolong Charger & Intelligent Discharger. I never opened the case and didn’t know to look for the sticker to date the battery to verify whether it is original to the car. This is my process:

    Date 2019/07/29: ‘04 Prius Hybrid Traction Battery long recondition 166,500 miles. Ambient temperature 75*F. The car normally gets 49 mpg and SOC usually hovers around 6 bars. -surprisingly good battery performance for a new to me 2004 Prius. Decided to recondition after a hot drive up a long incline to Joshua Tree (with A/C switched On) made the car go into one bar purple and the engine run noisy in “battery protection mode” for the first time.


    Chrg1: 14 hours 239V 342mA

    (Started 6:30pm @ 226V, rose to 238V by 12:30am, remained at 239V by 8:30am when discharge cycle started.)

    Dschrg to 134V - 8.5 hours

    (Bounced to 177V when I saw it)


    Chrg2: 21.5 hours 235V 322mA

    (Started 5:20pm @ 177V, rose to 228V by 1:00am, found it at 234V @ 8:00am, 235V @ 9:45, 236V @ 10:20, 12:30, 2:30, dropped to 235V @ 3:00pm when discharge cycle started.)

    Dschrg to 84V - 6.5 hours

    (Bounced to 180V when I saw.)


    Chrg3: 21 hours 235V 323mA

    (Started 9:30pm @ 180V, 230V @ 6:30am, 233V @ 9:30, 235V @ 12:00pm, 236V @ 4:30, 235V @ 6:30 when discharge cycle started.)

    Dschrg to 84V - 5.25 hours

    (Bounced to 163V within 30 seconds!)


    Chrg4: 34 hours 238V 232mA (Started 11:45pm @ 163V, rose to 233V by 11:00am, 237V by 12:00am, 238V by 9:30am. (Waited several hours before the test drive).


    Results:

    The car drove well and got good mileage even before the reconditioning. The results of three cycles are subtle but the car does appear to perform better insofar as the HV battery now largely stays at 6 bars, rarely goes into green and has yet to reach 8 bars. I saw it dip down to purple once when I parked the car but kept the A/C running but never during actual driving. Efficiency remains the same at 49 mpg with no dramatic changes in engine performance.

    Now after 4 months and driving 2k miles the reconditioning showed marked improvement to the traction battery. I’ve only seen the battery reach 8 bars once in 4 months and turn purple twice. It now likes to stay in the blue and does hover between 6 bars and 7 bars. I regularly get calculated 49-50mpg at the pump with computer estimating 51+mpg. I drive conservatively with my eye partially on the computer while on the freeway (aired 40psi on the tires) but otherwise do not bother with hypermiling games.

     
    #2403 Ed69, Oct 30, 2019
    Last edited: Oct 30, 2019
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  4. Phildo

    Phildo Active Member

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    You'll most likely find that the charger won't discharge the modules at 5A.

    Sure, it will for a small, single-cell battery, but not for a six-cell Prius module.

    (Note: Huge lack of knowledge here, so it will be a vague answer.)

    Discharge depends on Watts and Voltage. It's the discharge wattage that you actually need to know about.

    I've got an iCharger 406DUO that discharges at around 10A. The 4010DUO discharges at around 20A.

    The old model Turnigy Reaktor Quadkore/Charsoon Antimatter 4x300W (ie identical) will discharge at 2.7A, increasing to 3.1A as the module voltage drops.
     
  5. Buphagus

    Buphagus Junior Member

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    How to do same test when car is running?

    My thought is to use the dr prius app in record mode and see the before and after result of a hard highway acceleration from 0 to 60 plus
     
  6. ianerickson34

    ianerickson34 New Member

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    Does another thread exist showing folks' success with diy module replacement/rebalancing? I would love to know how many miles one has achieved before the red triangle comes back after utilizing the rc charger techniques. I'm about to undertake this project myself to get my 2007 prius back on the road then sell but I want a clear conscience that it will last a good while for the next owner.

    SM-G930V ?
     
  7. Ed69

    Ed69 Junior Member

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    My 2-cents, if you just want to sell is to have a hybrid shop do it and get a warranty. Even a 1-year warranty will make the seller feel more confident about buying the car. This is if you live in an area that has many Prius specialists like LA that will rebuild and rebalance for $600 with warranty.
     
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  8. ianerickson34

    ianerickson34 New Member

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    That's the solution I'm arriving at as well. I have a good shop a couple hours away that I'll likely go with. Thank you!

    SM-G930V ?
     
  9. Frank1234

    Frank1234 Member

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    am new to the chat so here my 2 cents,, if you going to sell it getting a warranty in the battery, doing the job in a shop will be the best bet, about how long will last to the red triangle to come back it will depend on how good the job gets done is my believe, many individuals just change the bad cell while others individuals change the bad cell and also test for any other cell that is weak doing a load test, the replacement cell should match the capacity as close as possible of rest of the other cells, meaning capacity of the cell it's what it matters, not the volts, you have to try to get the same capacity and I read that hybrid automotive can get you the capacity you need with only the year and miles from your car after you replace the bad cell you need to balance and volt on each cell even out on every one since capacity will be no 100% equal I recommend a grip charger to keep a balance, otherwise when the volt different get to high expect to see the triangle again even if all the cells are good this is my opinion.
     
  10. ianerickson34

    ianerickson34 New Member

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    Hey everyone, I have a brand new, unopened, Charsoon Antimatter 4 channel, 20A charger for sale for $250. Avoid the 3 MONTH shipping time from China. Was going to use it to rebuild my battery but taking it to a shop instead. Let me know if anyone is interested!

    SM-G930V ?
     
  11. George W

    George W Active Member

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    but the new ones are listed for less than what you are asking.
     
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  12. SFO

    SFO Senior Member

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    Without putting members on the spot, does anyone have the recipe for the secret sauce knowledge below?

    "We developed a process that restores every module (except the ones that already failed) back to 6AH and it's accomplished in a single cycle of the module."

    If known, or even where it might be hiding, could someone please send me a PM or post it here for all to share :)
     
  13. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

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    You can technically make those claims without making the cells any better for Prius usage without doing anything other than a couple charge/discharge cycles. Or a heavy discharge and quick charge cycle. NiMH doesn't have the cadmium that grows those crystals of doom like NiCd batteries but the nickel plates still do get deficiencies over time. Otherwise they don't "lose" capacity in the traditional sense. If you were to do your capacity tests at a few mA rates, you'd see no change from new.

    But that doesn't help in the Prius...
     
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  14. Frogblast

    Frogblast Junior Member

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    I’m still working my way through this epic thread, but I wanted to check/confirm a few things for my car that finally hit P0A80. So after trying to figure out this thread’s history (I haven’t read nearly all of it yet, still working through it), I have a ton of questions:

    Is there any value in trying to use the ODB-reported voltage values while driving to diagnose how many bad banks I have, or should I jump straight to disassembling the pack and testing individual cells?

    I’ve seen some YouTube videos that just take off the bus bar, and measure voltage across each pack, without any particular conditioning or load. I’m guessing that leads to inaccuracy depending on how much each cell happened to be charged when last used?

    To measure voltage w/ load (such as the halogen bulb approach: is there a better way?), does each cell need to be charged or conditioned first, or is the initial condition irrelevant? (ie, only the change in voltage is relevant?).

    When using the battery conditioning devices, I see all the spreadsheets showing the mAh consumed during each of the 3 discharge/charge cycles. What are those numbers being used for? Is this an alternate way of doing the ‘load testing w/ halogen bulb’).

    What are the generally accepted criteria for a ‘bad’ cell? Is it just more-than-average voltage drop during the load test? Or is it also the mAh produced during discharge? Is that ‘mAh discharged’ the value that you’re trying to keep balanced across all cells in the pack? Is it only relevant for the last cycle?

    What specific value are people referring to when saying that the cells need to be balanced? (My best guess is either the 3rd cylce discharge mAh, or charging to a specific voltage before installation?) What breaks when this is imbalanced? How close is ‘balanced’? (I’ve seen 500mAh thrown around?)

    How do you end up finding replacement cells that are well matched with the cells you already have? Most aftermarket/recycled cells seem to guarantee a particular capacity, but is it possible that cell might be ‘too good’ and not match the rest of my old cells?

    Is there a turnkey step-by-step process assembled somewhere, rather than having to glean it from the epic history of this thread? I’m finding it somewhat difficult pulling it all together (but I have some time to figure it out... My car doesn’t have to go anywhere for a month).
     
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  15. Frogblast

    Frogblast Junior Member

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    I finally viewed this video on YouTube (which has been linked previously in the thread), that ended up answering almost all of my questions:


    I guess I’ll try to summarize that here, and hopefully if I got it wrong, someone could correct me:

    There are three independent tests being done. (I ended up confused by intermixed conversations about the various tests). For a cell to be considered good, it must pass all 3 tests:

    a) Initial check of per-cell voltage straight out of the car, under no load. In a well behaving battery, all cells should be at the same voltage, because the car wants to maintain them in that state. Any that are lower than the rest are already bad.
    b) Load test (w/ halogen bulb) with the batteries straight out of the car: If some cells end up with a greater voltage drop than the rest, the cell is bad (each cells should be starting from around the same place, since we’re only considering cells that passed test (a)).
    c) Attempt to restore capacity in the surviving cells via the 3x charge/discharge cycles (or more than 3x, in the video). Discard any cell that doesn’t produce 6000 or 6500 mAh for the final discharge?

    And finally, during the re-install process, the voltage across the cells need to be leveled across the cells. It doesn’t particularly matter what the target voltage is, along as each cell is charged/discharged to roughly the same value.

    Did I get somewhere close to reality?

    The voltage leveling part leaves me with one idle question: I can’t imagine everything would stay in sync by itself across 10 years and 200K miles without some process always pushing the cells to have similar voltage levels. Is that the case or not, and if so, why wouldn’t it work if you just put in a bunch of non-voltage-leveled cells?
     
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  16. dolj

    dolj Senior Member

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    You seem to have captured the essence of the process.

    I'm not sure you can restore an old module to 6500 mAh, but it could appear to do so if your charge rate was gentle enough. The important thing is to do the same thing – i. e. being consistent.

    You can build a workable battery even if all modules are only 3000 mAh capacity.

    In regards to terminology, it helps with clear communication to use the same names for things.

    These are modules:
    Prius Gen II HV Battery Module.jpg
    and are the smallest unit that you can work with. It is made up of 6 cells.

    A Prius Gen 2 HV (hybrid vehicle) battery is made up of 28 modules connected in series. Modules are paired into 14 blocks which is the smallest unit the battery ECU monitors. This means the battery also consists of 168 cells connected in series (28 x 6).

    I hope this helps.
     
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  17. spdracrm3

    spdracrm3 Member

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    I've had good success at work proving bad cells by graphing the 14 voltage data pids and load testing them by driving wot in reverse in an empty parking lot 3 times (massive load as It just uses electric motor and is largest load you can put on the HV battery) and between each pass going forward (engine will start and recharge)till engine stops then repeat reversing. We use a recording snapon scanner that will also show max/min for each block and will wirelessly transmit to desktop from which I print out graphs and can show customers. 100% I find data matched code for bad block/cells which will have lowest voltage under extreme load and highest voltage during recharging.

    Rebuilt my 175k 04 pack by cherry picking best cells from 3 tested as above HV batteries (lowest recharge voltage, highest discharge voltage) still going strong after 10k miles 52mpg and .1V max difference between blocks. I monitor using Dr prius and OBDLink. Never balanced them just let HV controller do its thing.

    SM-G960U ?
     
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  18. Albert Barbuto

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    I've had good results doing pretty much the same as the above post. (spdracrm3) I back up a small hill, just down the street from where I live. Backing up gently can easily draw 50-60 amp from the pack. I capture the data with Torque Pro, and a Canon Powershot on movie mode. This method is fast, easy, and inexpensive...
     

    Attached Files:

  19. dy/dx

    dy/dx Junior Member

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    This works for me, correct me if I'm wrong. I had enough time to do this, you can adjust yours based on your spare time. Please note that this is just a guide based on my opinion and the opinions of others. It may not be 100% correct but it isn't 100% wrong. Inputs are welcome. Approximately 21,000 miles after rebuild. I do approximately 20,000 miles a year.

    BATTERY SPECIFICATIONS:
    Module capacity: 6500 mAh.
    Minimum acceptable capacity: 4000 mAh
    Load testing range: 7.0 v - 7.9 v
    Resistance range: 10-15 milliohms
    Self discharge rate: 0.1V per month
    Nominal voltage: 7.2V
    Resting voltage: 7.8V - 7.9V
    Charge efficiency: approximately 70%
    Module number: 28 close to ECU (GEN2)

    CHARGER SETTINGS:
    Mode: Program Save then Program Load
    Battery type: NiMH
    Nominal voltage: 7.2V
    Charge current: 650mAh
    Charge capacity: 9200mAh
    Discharge voltage: 6V
    Discharge current: 1A (or highest current)
    DCHG>CHG: 3 cycles
    User Set Program:
    Capacity Cutoff: 9200mAh
    Safety Time: off, (time doesnt matter)
    Temp Cutoff: 45C (using temp probe)
    Waste Time: 10mins.
    Delta peak: 15mV

    BATTERY TESTING AND RECOVERY:
    1. Measure open circuit voltage and identify bad modules. Record voltage range.
    2. Apply load with H4 bulb with low and high beams connected together for 2 minutes. Record the voltage difference and identify bad modules. Difference between modules not more than 0.3V.
    3. Discharge good modules to 6V and charge to capacity of 9200mAh (3 cycles). Discard modules less than 4000mAh. Capacity to be determined by the last discharge cycle. Leave modules compressed in the casing when charging.
    4. Let battery rest for 7 days and check open circuit voltage to see excessive self discharge rate. Identify bad modules.
    5. Connect all good modules in parallel for 12 hours to equalize the voltages, then record equalized voltage range.
    6. Perform second load test. Apply load with H4 bulb with low and high beams connected together for 2 minutes and check for bad modules. Difference between modules not more than 0.3V.
    7. Buy used modules with similar capacities to replace bad modules. Repeat steps 1 to 6 for new modules. Note: conduct load test within the recorded voltage range in step 1 and 5.
    8. Discharge new modules and good old modules to the range of 7.2-7.6V.
    9. Match modules into blocks by difference in voltage during second load test (step 6). Total of voltage drop of two modules in each block to match the remaining 13 blocks. Strongest block to be in the middle if possible.
    10. Connect all 28 modules in parallel for 12 hours to equalize the voltages. Voltage difference not more than 0.3V.
    11. Install battery in the car.

    TIGHTENING TORQUE:
    Upper battery carrier: 5.5Nm
    Upper battery cover: 8Nm
    Battery Assembly: 19Nm
    Frame wires: 5.6Nm
    Battery carrier panel: 7.5Nm
    Remaining brackets: 28Nm
    Buss bar nuts: 5.4Nm

    GENERAL INFORMATION:
    1. Don't clean the busbar nut, replace it if necessary.
    2. Use the highest capacity modules on block #1, #7/#8 and #14.
     
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  20. dolj

    dolj Senior Member

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    Very nice summary. I can't verify some of your information one way or the other as I haven't used hobby chargers.

    The only standout for me is (and I mention it more those that follow along):
    You can save yourself 24 hours by not doing this at all. It has been discussed somewhere back in this very thread. The recommendation and the reasoning behind it were put forward by one of the respected (and a professional) PC members, but essentially there is not enough potential difference between any one module to make enough electrons flow in any direction to achieve any sort of equalization. Just ensure the modules are charged to the same voltage – and this assumes that the process you outlined results in closely matched modules in your battery. It is not a shortcut to avoid doing the work. If your modules set is not closely matched, you will be going back in, in the not too distant future.

    By way of comment and in no way a criticism:
    I personally like 7.9 V/module as this will give the car a 60-65% SoC when the battery is back in use. Just to elaborate a bit more, at 7.2 V/module, the entire 28 module battery is entirely discharged, and I personally wouldn't install a battery at this voltage, so I don't know what would happen if you did, but I wouldn't go lower than 7.7 V/module which would give 40% (no bars on the MDF). Finally, if you wanted to have 80% (8 bars on the MDF) 8.15 V/module is the target to aim for.

    But once again, a very nice summary and it will make it easier for those that follow. I for one, appreciate the effort you have made to make it.

    Cheers.
     
    #2420 dolj, Apr 16, 2020
    Last edited by a moderator: Apr 18, 2020