Can I use a 3S2P configuration with Battery Protection Board? Please see image

Discussion in 'Power Electronics' started by pmap93, Sep 6, 2016.

  1. pmap93

    Thread Starter New Member

    Aug 15, 2016
    15
    0
    hello and good day!

    I'm in the last stage of the project in my little portable speaker. But I'm having doubts with the Battery Protection Board.

    Power Electronics make me nervous, especially with Lithium ion.

    The board claims it's only for a 3S 18650 (or similar voltage) battery. But I want to double the mAH (capacity), so I decided to use 3S2P configuration. My question is, is it safe? Will it have problems?

    The Batteries I'm planning use are the Panasonic NCR18650B.
    (Which I'm guessing is having it's own protection already, better safe than sorry):
    [​IMG]


    This is the wiring I was planning:
    [​IMG]

    VERSUS the original from eBay:

    [​IMG]

    I hope it's clear, and i hope for someone to reply soon :)

    Regards,
    Paolo
     
  2. ian field

    Distinguished Member

    Oct 27, 2012
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    784
    2P, 3P and sometimes even 4P turn up in laptop packs, its simply how they end up with the sum of the capacities without huge bulky cylindrical packs.

    Just make sure your controller module is rated for the Ah capacity you end up with.
     
  3. pmap93

    Thread Starter New Member

    Aug 15, 2016
    15
    0
    Hello and thank you for your answer!

    Just to be clear, the charging controller is an IC on the board? If so, which one? Can you please direct it to me?

    This is the board
    https://www.ebay.com/itm/321779081018

    It doesn't show much information about its mAh Rating.
     
  4. ian field

    Distinguished Member

    Oct 27, 2012
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    Its advertised as an 18650 guard plate - typical capacities are usually somewhere in the general direction of 2200mAh.

    If you want to protect higher than that - buy something that's advertised to do so.
     
  5. pmap93

    Thread Starter New Member

    Aug 15, 2016
    15
    0
    Can I buy TWO of these and have to separate 3S packs and connect them in Parallel?

    |==Batt]=[Batt]=[Batt]==[Protection Board]===|
    | --------------------------------------------------------|
    |==[Batt]=[Batt]=[Batt]==[Protection Board]===|

    |
    ---------------------------------------------------------|
    [GND]------------------------------------[Output of around 12V]
     
  6. ian field

    Distinguished Member

    Oct 27, 2012
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    I'd contact the manufacturer and ask - but my gut says its not advisable.
     
  7. pmap93

    Thread Starter New Member

    Aug 15, 2016
    15
    0
    Thanks very Much.

    I'll avoid eBay for now and look for more reputable resellers of Battery Protection modules
     
  8. ian field

    Distinguished Member

    Oct 27, 2012
    4,415
    784
    Lithium cells are very high energy density - if it gets out all at once, you'll have a fire on your hands.

    Its best not to take chances, at least till you know which ones are calculated risks.
     
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