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got some young 2012 modules

Discussion in 'Generation 1 Prius Discussion' started by scotman27, Apr 10, 2014.

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  1. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Touch the modules and see if any of them feel 'warm'. If you have a thermometer, put it in the temperature probe, hole and read it out. My personal feeling is 100F is "Ok" we got enough. Over 110-120F, time to stop and let that one cool off and rest for a couple of days.

    When you go to 'pair' the modules, you'll need to match the weak and strong. Then put the best pairs in the middle of the pack and weakest pairs on the ends. This will tend to even out the heat load in the future.

    Bob Wilson
     
    #141 bwilson4web, Apr 21, 2014
  2. scotman27

    scotman27 Active Member

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    no they feel cool to the touch. just shot them with my temp gauge, around 50 to 60 degrees Fahrenheit.
     
    #142 scotman27, Apr 21, 2014
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  3. scotman27

    scotman27 Active Member

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    only thing i dont like is the voltage getting up to 8.7v. but i guess i shouldnt be worried because ive seen on my scangauge while braking the voltage of a bunch of pairs getting to almost 18.3v with my current battery. they come back down almost immediately but ive seen it get that high coming down a long hill.
     
    #143 scotman27, Apr 21, 2014
  4. scotman27

    scotman27 Active Member

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    when I get this done and run these numbers to you regarding the four modules that I'm cycling right now, if they check out with you. should I cycle the rest of the pack. I feel that I should but I want to check with you guys first.

    Samsung galaxy precedent
     
    #144 scotman27, Apr 21, 2014
  5. usnavystgc

    usnavystgc Die Hard DIYer and Ebike enthusiast.

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    In order to do it right, you need to cycle all of them so you can match the weak with the strong and inevitably,
    "balance" the pack. :)
     
    #145 usnavystgc, Apr 21, 2014
  6. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Agreed but only do:
    • discharge to normalize start
    • charge to dV/dt or charge limit
    • discharge to measure capacity
      • (put aside for parallel charge)
    What this does is you can quickly scan the modules to rank them. Then put them all in parallel to charge up to your assembly voltage. Done!

    Bob Wilson
     
    #146 bwilson4web, Apr 21, 2014
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  7. scotman27

    scotman27 Active Member

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    what do you mean by discharge to normalize start

    Samsung galaxy precedent
     
    #147 scotman27, Apr 21, 2014
  8. bwilson4web

    bwilson4web BMW i3 and Model 3

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    No one knows how much charge is on a module, initially. So a discharge to 6.0V puts the modules in a known, discharge state with most of the reactive chemicals in a know, initial state. The subsequent charge works against all of the reactive chemicals in the module. But as you've notice, sometimes the charge does not dV/dt stop. That is why we don't use the charge Ahr as the capacity. Regardless of the charge stopping mechanism, at this point, the module is as fully charged as anyone knows to accomplish.

    The next discharge actually measures the capacity of the module. This is the one useful for matching modules.

    Normally, the charger would then cycle into 'charge mode' but you have an advantage. You have mastered how to wire the modules in parallel and charge them all to the same ending voltage. This is brilliant and much better at getting all modules to a common state of charge before assembly.

    Bob Wilson
     
    #148 bwilson4web, Apr 21, 2014
  9. scotman27

    scotman27 Active Member

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    When I recharge, should I keep the charge limit at 7000mah?
    Run 2 cycles of charge /discharge ?
    Or 2 cycles of discharge/charge?
    Mind you when I do this ill probably be at work or sleep for most of the cycling. because I cannot do this when I'm just at home I'll never get it done

    Samsung galaxy precedent
     
    #149 scotman27, Apr 21, 2014
  10. scotman27

    scotman27 Active Member

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    A couple of these are just starting their third cycle of discharge. Should I stop them around the 7.4v mark?

    Samsung galaxy precedent
     
    #150 scotman27, Apr 21, 2014
  11. bwilson4web

    bwilson4web BMW i3 and Model 3

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    If they were mine, I'd probably stop at 6.0-6.5 Ahr as I've never seen one higher than about 5.1-5.2 Ahr.

    I would follow the second as that is also how the MRC 989 works.

    I often did this while working too.

    Bob Wilson
     
    #151 bwilson4web, Apr 21, 2014
  12. scotman27

    scotman27 Active Member

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    okay so I'll drop the milliamp cutoff down to 6500, 2 cycles of discharge/charge.

    Now the ones that are just beginning the third cycle of discharge before charge, should I shut then down when the get about the 7.4volt mark?

    Samsung galaxy precedent
     
    #152 scotman27, Apr 21, 2014
  13. scotman27

    scotman27 Active Member

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    ok got some numbers:
    module 11:
    d1 2507
    c1 7000
    d2 6094
    c2 7000
    d3 1388
    c3 0285 (i accidently disconnected the wires)

    module38
    d1 3803
    c1 4272
    d2 4122
    c2 3880
    d3 3830
    c3 4206

    let me know what you think
    these two are done and i believe are the strong ones.
     
    #153 scotman27, Apr 21, 2014
  14. scotman27

    scotman27 Active Member

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    the only thing i dont like is that third discharge. on module 11
     
    #154 scotman27, Apr 21, 2014
  15. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Comments inserted
    * * Start * *
    ok got some numbers:
    module 11:
    d1 2507 # Was this the first discharge after parallel charge and partial discharge?
    c1 7000 # The dV/dt did not work, which happens and makes other results suspicious
    d2 6094 # Trustable Ahr capacity, most good. Was this an end-module?
    c2 7000
    d3 1388 # Weird but let it rest for 2-3 days and retest.
    c3 0285 (i accidently disconnected the wires)

    module38
    d1 3803
    c1 4272 # YEA! The dV/dt worked
    d2 4122 # Use this as the capacity
    c2 3880
    d3 3830
    c3 4206

    let me know what you think
    these two are done and i believe are the strong ones.
    * * End * *

    This shows why I don't like using a high Ahr limits because it potentially leads to overcharging the module. Overcharging leads to gas formation and heat. That module 11 did not trigger the dV/dt could be due to a slight imbalance of the six cells doing their dV/dt at different times. It could also be insensitivity of the charger to the dV/dt change. Regardless, let the module sit for 3-4 days or as long as possible so the internal chemistry can recombine the gas into water. On retest, try to use a smaller charge current. It will take longer but be less stressful for the module.

    Bob Wilson
     
    #155 bwilson4web, Apr 22, 2014
  16. scotman27

    scotman27 Active Member

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    omments inserted
    * * Start * *
    ok got some numbers:
    module 11:
    d1 2507 # Was this the first discharge after parallel charge and partial discharge? YES
    c1 7000 # The dV/dt did not work, which happens and makes other results suspicious
    d2 6094 # Trustable Ahr capacity, most good. Was this an end-module? NOT SURE
    c2 7000
    d3 1388 # Weird but let it rest for 2-3 days and retest. WEIRD IS RIGHT
    c3 0285 (i accidently disconnected the wires)

    module38
    d1 3803
    c1 4272 # YEA! The dV/dt worked
    d2 4122 # Use this as the capacity
    c2 3880
    d3 3830
    c3 4206

    let me know what you think
    these two are done and i believe are the strong ones.
    * * End * *

    ok i recycled the module 11
    discharge 5155
    charge 7000
    ahhhh much better.

    module 16:
    D1: 2019
    C1: 7000
    D2: 6101
    C2: 7000
    D3: 6299
    C3: 7000

    Module 19:
    D1:3308
    C1:7000
    D2:6068
    C2:7000
    D3:6238
    C3:7000

    Looking good so far :)
     
    #156 scotman27, Apr 22, 2014
  17. scotman27

    scotman27 Active Member

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    OK what do you recommend for cycling the pack. '
    here are my settings: correct my settings with bold.
    Discharge cutoff: 6v
    mah charge cutoff: 7000
    charge: 2amp
    discharge: 1amp(highest it can do)

    Delta v/vt: Default

    my question is if you set a higher mah cutoff doesnt that force the inbalance cells in the module to catch up to the ones that are already charged? so should i keep the mah cutoff at 7000 and decrease the charge amps to 1amp? Im going to start cycling the modules starting from the left hand side., but am waiting on feedback as to whether I should keep my current settings or change them before I begin. I think I got good results for what i have it set at so far but i most certainly dont want to destroy a module.
    I know that guy in that one thread that brought his capacity back on his 05 (Prius Battery rebalance thread | PriusChat) had great results using the same charger I have and he posted his settings on the forum so thats where I started with my settings.

    Let me know what to do, I leave for work around 11:30 and want to get these on cycle beforehand.

    thank you,
    Scott
     
    #157 scotman27, Apr 22, 2014
  18. KhaPhoRa

    KhaPhoRa Member

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    Yes, overcharging will help balance the cells. Technically it's the bad cells that reach capacity first and the good cells catch up. It's a death spiral: bad cell over charges and degrades, reduces capacity and over charges sooner next cycle and degrades, reduces capacity and overcharges sooner next cycle, etc etc. balancing is definitely good. What really helps these packs last as long as they do is the narrow "state of charge" they are kept in, so an unbalanced cell really takes a long time to develop into a problem. If you have time and really want to balance in the safest way possible, a charge current of 500ma is the way to go. In my tests however one or two cycles of overcharging at a faster rate won't flat out destroy these modules, you might theoretically lose some miles at the end of the packs life, but to what extent I can't say.

    Edit: just make sure to manage the swelling of the modules.
     
    #158 KhaPhoRa, Apr 22, 2014
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  19. scotman27

    scotman27 Active Member

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    the pack is clamped together.
    I bumped my charge rate down to 1amp, discharge/charge 2 cycles. starting with modules 1 thru 4
     
    #159 scotman27, Apr 22, 2014
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  20. scotman27

    scotman27 Active Member

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    i just got home from work, they are just starting their second cycle discharge first. gees thats taking long, i guess thats a good thing. i have the mah set for 7500 per a thread made up by brit prius that balanced and regained lost module capacity. the four are slightly warm but nothing to be concerned about. ill shoot them with the temp gun again
     
    #160 scotman27, Apr 22, 2014
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