Batterypack 3S3P

This is a 18650 3S3P batterypack for various applications where you need 12V.
I am using it for my 300W DIY bluetooth speaker as a power source for example.

Size: 20cm x 9.5cm x 4cm

Parts

• 9x 18650
• 3x 10A BMS
• 2x WAGO clamps (5 slot)
• 1x XT60 connector female
• 0.8mm² wires
• 2.5mm² wires
• ferrules
• screws M3x10 (for plastic)
• double-sided sticky tape

Instructions

Just print the four parts, put the batteries in place and screw the bridge above them.
Attach the 3 BMS with some two-side sticky tape on top of the bridge and then solder the wires to the BMS's in order, otherwise you might damage it.
For each 3 cell block solder/spot weld:

1. positive from first cell to negative of second cell
2. negative from second cell to positive from thrid cell
3. negative from first cell to 0v BMS
4. positive from first cell to 4.2v BMS
5. positive from second cell to 8.4v BMS
6. positive from third cell to 12.4v BMS

After soldering all three blocks, glue the two WAGO clamps in place with sticky tape also. Then solder wires to all negative outputs of the BMS's and crimp ferrules to their ends. Stick those crimped (negative) ends all into one of the WAGO clamps. The same with the positive output (to the other WAGO clamp!).
Then solder two wires (2.5mm²) to the XT60 female connector, crimp their other ends and attach them to the WAGO clamps.
Screw the pullguard over the outgoing wires and attach the upper case.

Disclaimer

Be carefull with 18650 batterys, they can be dangerous if not handled properly!

If you have any suggestions for design, functionality or safety improvements, feel free and leave a comment.
Hope the thing works for you :)