Possible Group Buy - Check Interest - Lithium Titanate cells

Discussion in 'Hobby Engineering' started by rainwulf, Jul 15, 2018.

  1. Sunder

    Sunder Member

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    Thanks. For a large quantity, if it made sense, I could engage a TaoBao agent, but for small projects, probably not worth it.

    I will keep it in mind though.
     
  2. aXis

    aXis Member

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    Just an update on my 24V 40AH yinlong LTO pack.

    I haven't finished my BMS yet (been flat out doing house renovations), but after 180+ days of use with about a 30% daily capacity cycle, the imbalance between cells hasn't really changed. The weakest cell is still the weakest, about 30mV below the average. The strongest cell is still the strongest, about 15mV above the average. Worst case imbalance has remained around 45mV the entire period.

    The trend of weak vs strong still seems to be driven by the position in the pack - the ones at the top weaker than the ones at the floor. They are sitting on foam on concrete, then suspended 20mm above that, but I still wonder if it's just thermal effects so I've flipped the pack upside down.

    Maybe the imbalance would be more significant and require management if I did deeper discharge, but at this point it's not a problem.
     
  3. OP
    OP
    rainwulf

    rainwulf Member

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    I have discovered that as well.. whatever imbalance is there stays there. They must be so damn coulumb efficient. I like to think of them as giant capacitors heh.
     
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  4. mtma

    mtma Member

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    Suggests that the factory quality is very consistent too
     
  5. OP
    OP
    rainwulf

    rainwulf Member

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    Well i have a dead 35ah!

    Expected - it was in a pack of 40s. The pressure cap vented, and its all dry inside.

    This weekend im going to cut it open for giggles.
     
  6. aXis

    aXis Member

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    Wild! Share some photos please.
     
  7. vk2fro

    vk2fro Member

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    Keen to see whats in it too, shoot a video and make sure you wear appropriate saftey gear in case it decides to go nuclear. :)
     

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