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How to tell a "good" blade from a "bad" blade?

Discussion in 'Gen 2 Prius Technical Discussion' started by kiwisteve, Aug 13, 2019.

  1. kiwisteve

    kiwisteve Junior Member

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    Location:
    Rotorua, New Zealand
    Vehicle:
    2006 Prius
    Model:
    Two
    I was having some trouble with my 2007 Gen 2 Prius. After troubleshooting, found out it was the battery ECU and the voltage sensing harness. A pin had burt out. Makes sense if you take a look at my previous post about my odd battery readings.

    I decided to try my luck at my local junk yard to see what I could find. Spent an hour looking and just when I was about to give up, I found a 2006 gen 2, all smashed up front and roof, but HV battery untouched. The junk-yard guy had no idea, so I offered him NZD$400, about US$275, for it if it still had the parts in it I wanted. I replacement ECU and harness was going to cost me NZD$600, so I thought I'd try my luck.

    I walked out of there with a complete battery, with a good ECU and harness. Battery is really good condition visually, no rusting or any leaking cells.

    I've moved over the ECU and harness to my Gen 2, and she is happy again, no error codes for over 500kms now.

    She does feel a little bit sluggish though, and it may just be me, but I feel like the ICE motor is running more than it should.

    There are a couple blades in the original pack in my Gen 2 than can't handle my load testing 12v 70w bulb for more than a minute before dropping to 6v.

    I have gone and charged all the cells in the junkyard pack, using my smart balance charger. Did them 2 at a time, took a few days. The pairs all accepted a good amount of charge, and I have tested them under load with the 70w light bulb. Most of the pairs were able to handle the bulb for 2mins before dropping under 13v, so roughly 6.5v per blade. I thought this was pretty good, am I correct?

    I know I need to run tests on the blades individually, this was just a quick way to see if any were really bad.

    What I am hoping to do is to try build the best pack possible out of the 2.

    So what I am wanting to get some help with is what sort of testing senario would people recommend to weed out the "bad" or "weak" blades. Ideally using my existing 70w light bulbs load.

    I sorta after something like:

    fully charge blade, rest x hours, if can maintain 70w load for 3mins before dropping to 6v, then good. If less than 2mins then weak, if less than 1mins, send to recycle depot.

    Then try to assemble the strongest, and most closely balanced pack of 28 blades.

    I know best way would be to get a fancy multi channel charger/discharger and cycle them, and work out remaining capacity, bit they are very hard to source in New Zealand, and very pricey.

    My smart charger can safely charger them up, it can discharge too, but only at 5w, so will never get anywhere.

    Any help and or advice would be greatly appreciated. :)

    Thank you in advance.

    Steve.

    Posted via the PriusChat mobile app.
     
    #1 kiwisteve, Aug 13, 2019
  2. spdracrm3

    spdracrm3 Member

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    2004 Prius
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    V
    I work at a shop so have access to a graphing/recording scan tool and what I've done on the batteries I've exchanged is do a load test on the cells using the best tool I think (the car itself ) the computer controlling the hybrid system is what has to be satisfied with the battery health and therefore I think will work best to test them . So I do three full throttle reverse accel runs in an empty parking lot ( it only uses battery in reverse) while recording the 14 cells on scan tool ,run forward till engine stops (recharge) between each run then print out results and compare graphs and max/min voltages .you can the use these to pick the cells with the least amount of change between lowest voltage (high load ) ,to highest voltage (weak cells take more voltage to recharge ),and computer looks for cells that are drastically different than the others ,which I think is all the fuss over "balancing the cells"). All the ones I've done had cell specific codes set when customer brought in with the dreaded triangle on which matched the cell that showed bad in this test I do

    Worked so far to pick good cells from three batteries and make one good one for my dialy driver 04 which is getting 50mpg consistantly

    Only disadvantage of this test is battery has to be in car ,but if done before removal data can be used.

    SM-G960U ?
     
    #2 spdracrm3, Aug 13, 2019
    kiwisteve likes this.
  3. kiwisteve

    kiwisteve Junior Member

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    Location:
    Rotorua, New Zealand
    Vehicle:
    2006 Prius
    Model:
    Two
    Thanks very much for your reply, very helpful.

    What software do you use for recording the battery data? I have been using Prius Doctor app, it shows the 14 blocks voltage data. Just don't think it will give me a read out of the min and Max voltages.

    Thanks again.

    Posted via the PriusChat mobile app.
     
    #3 kiwisteve, Aug 14, 2019
  4. dolj

    dolj Senior Member

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    I'd be tempted to try and keep all the modules (blades) in the "newer to you" pack together, if possible. So, to that end, I'd do a three cycle charge/discharge (discharge each pair of modules (block) down to 9.6 V; 7.2 V and 6.0 V respectively) on all the modules of the "newer to you pack" and then do a final balance charge of all modules. Reassemble and install in your car. There is another pair of apps – Hybrid Assistant and Hybrid Reporter, I think they're called – that you could then do some health check and analysis type testing on the battery in car.

    I think that would be better than trying to build a frankenbattery.

    Just my 2c worth.
     
    #4 dolj, Aug 14, 2019
  5. spdracrm3

    spdracrm3 Member

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    We use a Snap On Solus pro scan tool and its software will record and print graphs
    SM-G960U ?
     
    #5 spdracrm3, Aug 14, 2019
  6. Skibob

    Skibob Senior Member

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    If you had an entire battery why didn’t you just install it and see what happened? I have never heard of a battery module being called a blade before. Is that some New Zealand thing?
     
    #6 Skibob, Aug 16, 2019
  7. ChapmanF

    ChapmanF Senior Member

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    Try slicing a tomato?
     
    #7 ChapmanF, Aug 16, 2019
    Skibob likes this.
  8. dolj

    dolj Senior Member

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    Not particularly a New Zealand thing. I have seen it here and there. I think whoever coined it had enough sense to know the module was a collection of cells so recognised they needed to use a term other than cells.
     
    #8 dolj, Aug 16, 2019
  9. ChapmanF

    ChapmanF Senior Member

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    In IT circles, individual computing elements made for high-density, hot-swappable server chassis have been 'blades' for a while.

    Using them on tomatoes can get very messy.

    As can trying to hot-swap a Prius battery module.
     
    #9 ChapmanF, Aug 16, 2019
    Skibob likes this.
  10. Skibob

    Skibob Senior Member

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    I use my blade on tomatoes all the time with great success. If I tried to cut a tomato with a battery module...Not so much.
     
    #10 Skibob, Aug 16, 2019
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