What I'm trying to accomplish is buidling a battery powered bluetooth speaker. In order to do it I'm using the following parts:

  • Bluetooth amplifier module
  • 3x Samsung ICR18650-26FM Batteries
  • Battery protection board
  • Generic 24w (12v 2A) wall charger

    Now, I actually have some doubts about how to properly connect the battery protection board to the bluetooth board and to the charging port. Would it be sufficient to connect all of them together in a T-like connection? I'm pretty sure that the wall charger will output enough current to power the board and charge the batteries at the same time since I will not blast it to full volume all day while charging it, but is it the correct way to connect them anyway?

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    • \$\begingroup\$ The ground needs to be referenced from the same point. \$\endgroup\$
      – Voltage Spike
      Apr 5, 2017 at 22:05

    2 Answers 2


    Generic 24w (12v 2A) wall charger

    That worries me. Chances are that it's not a charger, but an AC adapter. If so, NO!, NO! NO!. You need an honest-to-goodness charger (current limited, proper voltage for three 3.7 V cells in series), not an AC adapter (wrong voltage, not current limited).

    how to properly connect the battery protection board to the bluetooth board and to the charging port.

    The charging port and the load (the Bluetooth board) are in parallel and connected to the P+ and P- of the BMS.


    As long as you follow all instructions and supply is adequate with 12.6V +

    enter image description here

    • \$\begingroup\$ I got that, but the thing I don't understand is the following: will it be enough to connect the two in/out ports of the board in the image above to the Bluetooth board power connector and tho the +/- leads of the charging port? I want to be able to use the speaker, while charging, without damaging the batteries. \$\endgroup\$
      – Szmoro
      Apr 6, 2017 at 6:29
    • \$\begingroup\$ Then you need a voltage >12.6 to charge and a current greater than charger and power amp to operate so a generic 24W charger will NOT DO IT. Update your question when you get these specs. It is critical. \$\endgroup\$ Apr 6, 2017 at 15:33

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