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got some young 2012 modules

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

  1. scotman27

    scotman27 Active Member

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    would it hurt or substantial decrease the accuracy if I bump up the amperage to two amps
     
  2. scotman27

    scotman27 Active Member

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    No im keeping them in compression for sure. i dont need one blowing up like a balloon.
     
  3. scotman27

    scotman27 Active Member

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    i started a cycle to hopefully get me an idea of what I got, one strong one weak. so far they have both come down only about 0.2 to 0 .4 v and it shows they are pretty equal after 1 hr its showing 0.7 a discharge(even though 1.0A is the highest discharge it will allow me to select) and 845mah at 7.09 to 7.11v they started out at 7.28 to 7.34. im guessing this is a good sign.
     
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  4. scotman27

    scotman27 Active Member

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    ok i was doing one cycle. they all got around 1600 mah discharge and i caught the one stopping around 7.0v. then i realized the stupid stop timer was set for 120mins. stupid me messed up the test. however i let it recharge at 2a and i had to stop the voltage at just shy of 8.4v and it showed almost 2300mah. now i know i messed up so sunday when I get home im going to resume the cycle on those 2 weak ones and 2 strong ones and see what happens. because im off monday so ill be able to keep an eye on them as well.
     
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  5. bwilson4web

    bwilson4web BMW i3 and Model 3

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    My experience has been that the charging Ahr is an unreliable number as these modules can be 'overcharged'. The excess charge is converted to heat and gas and results in lower discharge values on subsequent charge/discharge cycles. So my module tags have number pairs:
    • charge - only IF the dV/dt trigger event occurs, usually just the first one. After the first or second charge, they typically stop only when the charge limit is reached.
    • discharge - the usable capacity as this is what the battery module dumped.
    To minimize damage because over charging leads to a loss of subsequent discharge capacity, I put a charge limit. This is typically is typically no more than 5.5Ahr. After the second discharge becomes the value I use for a module. With the MRC 989, a cycle consists of:
    1. initial discharge to the lower limit voltage - typically 6V for these module or 1V per cell. Since we don't know the initial state, this number is not useful
    2. initial charge to the dV/dt or charge limit, typically 5.5Ahr - if the module reaches the charge limit, it is usually not a good sign. It means the dV/dt failed to stop the charge. Because I get no indication of what stopped the charge, I record but don't really worry about this value until I have several others. Exceeding 8V per module is overcharging the modules that reduces capacity.
    3. first full discharge to 6V per module - this is the initial Ahr capacity and typically the maximum that will be seen.
    4. second full charge to dV/dt or charge limit - if the charge stops before the charge limit, we know the dV/dt logic worked. This is always higher or equal to the first full discharge but not usable for module Ahr capacity. It is only discharge capacity that has any use . . . but then the module has no charge and can not be used for anything else.
    5. subsequent discharge/charge cycles - interesting to establish a pattern but always I find lower discharge capacity than the first. I see no evidence that cycling these modules increases capacity.
    So when I see a report of charging to '8.4V', well I'm glad these are not my modules. One of the reasons for using a low charging current is these modules are somewhat tolerant of low, current, overcharging. The literature points out and a temperature probe confirms the temperature rises, swelling shows the internal pressure grows, as the internal chemistry converts H{2} and O{2} back into H{2}O and a bunch of heat. In overcharge, the module is just an expensive resistor.

    Bob Wilson
     
  6. scotman27

    scotman27 Active Member

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    so when those got to 8.38 thats not a good sign then?
    so are these junk?
     
  7. scotman27

    scotman27 Active Member

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    i know they werent even warm, they were cool
     
  8. bwilson4web

    bwilson4web BMW i3 and Model 3

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    These modules are fairly tolerant of some over-charge especially at low amps . . . unlike some LiON batteries. But no battery likes it. This really is a case where ~8.0V should be considered, in my opinion, the maximum. I have seen as high as 8.8V using my MRC 989 BUT there was no charge happening. The modules were just getting warmer and warmer.

    They are still good and given your discharge only went to 7.0V and you saw 1.6 Ahr, I'm expecting you'll find about 3.5 Ahr capacity. There is a heck of a lot of charge remaining between 7.0V and 6.0V.

    Bob Wilson
     
  9. scotman27

    scotman27 Active Member

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    so how would i set this charger to shut it off at 8.1v instead of letting it run up like that? because I highly doubt ill get thermal runaway at those charge rates, ill probably cycle the whole pack. even while im at work, that way maybe in a week or so i can have a decent pack.

    i can assume that at 3.5 ahr, that I could possibly recondition this pack to maybe 5ahr which would be great. i know there is another post on here about a guy that did it with his 2007 pack and brought it back to capacity.

    this thread and he used the same charger im using the hitec x4 plus
    Prius Battery rebalance thread | PriusChat
     
  10. scotman27

    scotman27 Active Member

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    only reason it stopped discharging at 7.0v is because i was a dummy and didnt turn off the timer and left it at 120 mins.
     
  11. scotman27

    scotman27 Active Member

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    sorry that thread was of a 2005 prius not an 07
     
  12. bwilson4web

    bwilson4web BMW i3 and Model 3

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    My experience has been that once the first, full discharge occurs, the module stays at the same or slightly lower, discharge capacity regardless of how many times it is cycled. I've only found one way to get the full capacity back but that is extremely experimental.

    After you swap the modules and have the car running with the new modules, I'll talk and show you how this experimental approach works. Understand, EXPERIMENTAL, which means the reworked modules may be considered junk afterwards. That is why we only want to do it with 'scrap' modules.

    Bob Wilson
     
  13. scotman27

    scotman27 Active Member

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    Ok, well hopefully mine will bounce back or actually be of a great capacity to begin with.
     
  14. scotman27

    scotman27 Active Member

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    Ok I'm home now, happy Easter to all. I am getting my charger setup and an going to cycle 2 strong 2 weak and see what happens, I got mah cutoff set to 7000. Discharge set to 1amp charge set to 2amp cutoff voltage set to 6volts. Using my hitec x4 plus. Let me know what you think.

    SCH-M828C ? 2
     
  15. bwilson4web

    bwilson4web BMW i3 and Model 3

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    I've not seen used modules having more than 5.1-5.2 Ahr capacity but I haven't been dealing with the newer style modules.

    I have one sample of the new style plus the 38 in my rebuilt pack . . . in service. Still, I probably would have started less than the 6.5 Ahr capacity of a new module. Still, you're at the leading edge.

    Bob Wilson
     
  16. scotman27

    scotman27 Active Member

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    ok so my modules are still cycling they seem to be pretty good. i believe they are on the 3rd cycle but im not sure. and i dont know how to check on this charger while its cycling. right now i got 4 of them(based on resistor test). 2 weak 1 strong on the discharge, 1 strong on charge
    here are the numbers currently:
    module11:strong) Discharge; 7.15v 5153mah
    Module16:weak)discharge 6.94v 5589mah
    module19:weak) discharge 7.29v 4332mah
    module38:strong)charge 8.24v 2117mah

    i think number 38 is bad. but im not sure. and im not sure if i should interrupt the cycle. but i know last night i watched it peak out at 4300 and some mah on charge before it did 5 mins waste time then started the discharge. the voltage was 8.34v and i think when i went upstairs this morning on discharge it was almost at 5000mah. so im not sure where the discharge ended on that.
    what do you think?
     
  17. usnavystgc

    usnavystgc Die Hard DIYer and Ebike enthusiast.

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    You only measured the charge cycle on 38. Run the discharge cycle and I'll bet you get a satisfactory number.
     
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  18. scotman27

    scotman27 Active Member

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    man i sure hope so. it seems weird that it would be bad. so far any type of charge or even the resistor test revealed voltages very steady with one another.
     
  19. scotman27

    scotman27 Active Member

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    so far its at 3270 mah with 8.44v. i have cutoff on all set to. 7000mah. is that acceptable. so far bob seems optimistic about my pack
     
  20. usnavystgc

    usnavystgc Die Hard DIYer and Ebike enthusiast.

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    I have followed this whole thread and it is my belief that every module you have is not only good or acceptable but, very good.