How to make a charger for 10 batteries

They asked me to make a charger. The main difference from many was the presence of 10 channels. People are going to charge some lead batteries. The batteries in them are installed in weapons for the laser tag. This charger, the device can be used to charge Li-ion.

For homemade work we need

• To install the device, I chose a box for wiring. The dimensions of the casing are 4 * 6 cm. It took a segment of half a meter.
  
• Since they gave me the old connectors, I will install them in a new design.
  
• You will also need double-sided tape. I took on a foam basis.
  
• For the plugs of the casing, I took a soft plastic. It seems like there are factory plugs, but I have not found such.
  
• The basis of our charge are boards on LM2596 from China (//ali.pub/3ge64l). They have resistors to adjust voltage and current. There is also a resistor for setting the indication of the end of charge.
  
• You also need a connector for connecting an external power supply. At the time of assembly. Its type has not yet been determined.

Assembly assembly

It is necessary to connect all the boards together. I applied a soft wire. We connect all the pluses among themselves, we also connect all the minuses. Having soldered 5 boards, I checked them. They work.
We connect all 10 boards in parallel to each other.
Glue double-sided tape. Its thickness is about 1 mm.
I cut such plugs out of plastic. They will be attached to super glue, there’s nothing military. Lean against the box and smeared with glue.
For reliability, I took a piece of plywood. I will fasten the box to it.
I made holes in the plywood, on the sides, to fix the device to the wall.
I make holes for wires in the side of the box.
Through the holes in the box, I turn on the wires, tying knots on the wires. I solder the wires to the boards, respectively polarity. In the center is plus, the outer cylinder is minus.
I installed a connector on the box. An external power source is connected through it. I connected 12.6 volts. You can do more, but this device can be connected in the car.
I solder the external connector.
I almost forgot the main thing. Batteries in automatic machines at 6 volts. The boards are configured at 7.3 volts, with the resistor closest to the incoming connector. The current is set to 0.12 amperes. Resistor closest to the output connectors. I did not wind up the charge control indication, it was not necessary. I turn it on. Everything is working.
This is how the finished device looks. So far I have installed 10 boards. As necessary, you can add four more, a place for them is calculated. Close the lid.
Such a simple charger turned out. People were satisfied with the result. This device can charge any batteries. The main thing is to configure the necessary parameters.