Charge Several Lithium Cells

Discussion in 'Power Electronics' started by william.in.rs, Jul 9, 2016.

  1. william.in.rs

    Thread Starter New Member

    Jul 14, 2012
    4
    0
    Is it possible to connect several PCBs like this one
    upload_2016-7-9_12-59-14.jpg
    to a circuit like this:
    Code (Text):
    1.  
    2.          |   |                 |          |          |
    3.          |   o-------|<|-------|          |-----     |
    4.          |   |                 |          |    |     |
    5.          |   |                 ------------    |     |
    6.          |   |                                 o-----o    
    7.          |   |                 ------------    |     |
    8.          |   |                 |   USB    |    |     |
    9.          o---|-------|>|-------| charging |-----     |
    10.          |   |                 |protection|         ===   3.7V          
    11.          |   |                 | PCB with |        -----  Lithium
    12.          |   |                 |   4056   |          |    cell        
    13.          |   o-------|<|-------|   DW01   |-----     |
    14.          |   |                 |   8205   |    |     |
    15.          |   |                 ------------    |     |
    16.          |   |                                 o-----o
    17.          |   |                 ------------    |     |
    18.          |   |                 |          |    |     |
    19.          o---|-------|>|-------|          |-----     |
    20.          |   |                 |          |         ===
    21.      +5V |   | GND             |          |        -----  
    22.       from PC PSU
    23.  
    24.  

    to charge several serila Lithium cells from a single 5V (PC) power supply?
     
    Last edited by a moderator: Jul 9, 2016
  2. Papabravo

    Expert

    Feb 24, 2006
    10,163
    1,796
    I have no idea what that collection of ASCII characters is about.
     
  3. Techno Tronix

    Member

    Jan 10, 2015
    140
    10
    I think yes, you can but it is risky as you have to maintain a balanced charge for each battery. It is not safe to charge multiple cells.
     
  4. ScottWang

    Moderator

    Aug 23, 2012
    4,855
    767
    That is one kind of ASCII code art and used the ASCII code to draw the circuits to save the space of hard disk.

    ASCII code art.
    Assorted ASCII Schematics.
     
  5. ScottWang

    Moderator

    Aug 23, 2012
    4,855
    767
    You could have a common ground and only using one Schottky diode to reducing the Vf from 0.7V to 0.3V~0.4V.

    If you use two diodes then the Vin of charge module only have
    Vin = 5V-(0.7V*2) = 3.6V, that is too less for the module to charge the Lithium battery as 3.7V (full charge 4.2V or some are 4.3V).

    The TP4056, Input voltage: 4v-8v.
    I'm not sure does it has raise the voltage(boost) or not, if no then you should do as what I suggested, if it has boost then using one 1N4001~4007 could be ok.

    Code (Text):
    1.  
    2.          |   |                 |          |          |
    3.          |   o-----------------|          |-----     |
    4.          |   |                 |          |    |     |
    5.          |   |                 ------------    |     |
    6.          |   |                                 o-----o  
    7.          |   |                 ------------    |     |
    8.          |   |                 |   USB    |    |     |
    9.          o---|-------|>|-------| charging |-----     |
    10.          |   |                 |protection|         ===   3.7V    
    11.          |   |                 | PCB with |        -----  Lithium
    12.          |   |                 |   4056   |          |    cell    
    13.          |   o-----------------|   DW01   |-----     |
    14.          |   |                 |   8205   |    |     |
    15.          |   |                 ------------    |     |
    16.          |   |                                 o-----o
    17.          |   |                 ------------    |     |
    18.          |   |                 |          |    |     |
    19.          o---|-------|>|-------|          |-----     |
    20.          |   |                 |          |         ===
    21.      +5V |   | GND             |          |        -----
    22.       from PC PSU
    23.  
    24.  
     
  6. william.in.rs

    Thread Starter New Member

    Jul 14, 2012
    4
    0
    Sorry, I didn't expect font change. This is the real schematic:
    upload_2016-7-9_17-37-47.png
    As you can see from schematic cells are connected serial, not serila, sory for typo.
     
  7. william.in.rs

    Thread Starter New Member

    Jul 14, 2012
    4
    0
    Thank you @ScottWang!
    As far as I know the PCB doesn't boost voltage.
    I was wondering about if it is possible to charge several serial connected cells from a single power supply rather than thinkihg about voltage drop. However, the advice to use Schottky diodes is great.
    As I intend to repack used laptop batteries I need some protection circuit which would turn the whole pack off and request charging whenever voltage of any cell goes below some limit. Any idea?
     
  8. ScottWang

    Moderator

    Aug 23, 2012
    4,855
    767
    Because the batteries are in serial, assuming that you using 3 batteries, the total voltages of batteries should be 12.6V, and you only have about 4.2V for charge modules, so this circuit only for one battery, if the batteries are not charge at the same time then it will be ok, but they can't charge at the same time.

    If you want to match your original idea then you have to using the boost circuit, and do some modify, or using 5V to charge the batteries as in parallel, but not really.


    TP4056_3.7V-Lithium-cel_william-in-rs.gif
     
  9. bertus

    Administrator

    Apr 5, 2008
    15,648
    2,348
    Hello,

    The circuit scott shows you will only work if the charging controllers are isolated from the 5 Volts.

    Bertus
     
  10. Ylli

    New Member

    Nov 13, 2015
    26
    9
    Simple answer is NO. These charge modules do not look like they isolate the output from the input, and you will end up shorting everything out through the common terminal. You would need charge controllers that isolate the output from the input so that the output was floating.
     
  11. ScottWang

    Moderator

    Aug 23, 2012
    4,855
    767
    You could isolated the charge modules to charge many batteries.

    TP4056_3700mV-Lithium-cel_william-in-rs-02.gif
     
  12. Papabravo

    Expert

    Feb 24, 2006
    10,163
    1,796
    Dear Scott,
    Nobody needs to save space on a hard disk any more, and I don't need you to tell me what it was, I was there when it was created. It was an abomination when it was created and it still is. In the original post the code tags were missing and it was unreadable.

    Your diagram at least makes sense.
     
  13. william.in.rs

    Thread Starter New Member

    Jul 14, 2012
    4
    0
    Thank you all guys, now I am allmost convinced that I will have to disconnect batteries from serial connection to charge them separately and to reconnect them to get higher (needed) voltage. However, monitoring each cell voltage for overdischarge protection should be done in serial cell connection. I would appreciate any idea.

    The original question arouse from my thought that following circuit might work (charging several serial connected battery cells from single winding of a transformer):
    AC_charge.jpg

    When I moved from AC to DC I have got following circuit which would work if previous is working:
    DC_charge.jpg
    And this was the unreadable circuit from my original question.

    Can somebody open my eyes and tell me where I was wrong?

    P.S.
    My intention was not not to save space on hard disk, I am just (from ancient times) used to draw schematics that way. As this was my first post to AAC I haven't expected that it could get unreadable form for which I apologize once again.
     
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