Help with 15 Cell LiFePO4 Battery Charger

Discussion in 'The Projects Forum' started by Ben12, Mar 17, 2015.

  1. Ben12

    Thread Starter New Member

    Mar 17, 2015
    3
    0
    Hello folks,

    I need help designing a 15 cell LiFePO4 Battery Charging System. I have no idea where to start. I've seen designs for 2-4 cell systems, is there a way I can expand those designs to operate on 15 cells in series? The cells are 3.2V nom with 100A/H. Ideally I'd like the charger to be a 2A charger.

    This is a link to the type of cell.

    http://www.ev-power.eu/Winston-40Ah-200Ah/WB-LYP100AHA-LiFeYPO4-3-2V-100Ah.html
     
  2. Papabravo

    Expert

    Feb 24, 2006
    10,145
    1,791
    Are you planning to make only one of these, or do plan to sell some?
     
  3. Ben12

    Thread Starter New Member

    Mar 17, 2015
    3
    0
    Making only one of these for a prototype design on a personal project.
     
  4. Papabravo

    Expert

    Feb 24, 2006
    10,145
    1,791
    Well I recommend that you try doing two or four cells at a time before you tackle 15. As I understand the literature they want you to charge them individually.
     
  5. ronv

    AAC Fanatic!

    Nov 12, 2008
    3,290
    1,255
    Seems like you should be able to do it.
    You will need a 55 volt power supply with current limit and 15 balance modules.
     
  6. Bernard

    AAC Fanatic!

    Aug 7, 2008
    4,172
    397
    I believe charging individually is for only the first charge. The statement on firse charge to connect all cells in parallel bothers me. For a $ 2133 battery, can not afford many mistakes. I did not see a suggested charging current but suspect for 100 Ah that 20 A would be in range; 2 A a little slow? A second or third reading might be in order.
     
  7. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,993
    745
    according to the datasheeet they recommend optimal charging at 50 amps, for 2 hours, your 2 amp will take 50 hours, so your going to need a 55V 50 amp psu.
     
  8. alfacliff

    Well-Known Member

    Dec 13, 2013
    2,449
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    one advantage of the lifpe04 batteries is that they dont need super critical charging systems. 4 cells in series can be used as a car battery, using the cars charging system with no modifications. other types of Li batteries can catch fire, explode, or other nasty things if charged wrong, just a little, but the life04 dont require specialized charging systems.
     
  9. Ben12

    Thread Starter New Member

    Mar 17, 2015
    3
    0
    Thank you all for the responses. I think I'm going to start with charging 2 cells at a time with an active cell balancing system. If that works I'll see if I can expand it upwards incrementally.
     
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