It is planned to use such a powerbank as an emergency source of energy (which will not take up space in your bag). The cost of such a device will be about 70 rubles, if you have a battery from your old phone at home.
Let's get started!
The basis of this device will be a lithium battery from a broken phone (but you can buy a new one). The capacity of such a battery is 1200 mAh. This is not enough to fully charge the smartphone, but in an emergency it will help a lot.
We will charge it with the help of such a charging module for lithium batteries. On the front, it has micro USB output, and on the back there is where to solder the battery (and on top there is a charge indicator)
The phone will be charged from the battery with the help of such a Chinese boosting module. On the front side we see such a USB output, and on the other - a platform for soldering the battery.
Everything is connected according to such a scheme.
By the way, you can use several batteries by connecting from in parallel.
Thus, their capacity will be added up. For example, you can use batteries such as 18650. By connecting them in parallel, we get a very serious battery. But the essence of this powerbank is to make it small, but compact.
Continue assembly
Carefully open the battery and get to two terminals (- +). In the case or on the board it will be indicated where plus and where minus. Transfer these values to the battery using a marker. Now we tidy up the wires with a soldering iron.
For structural rigidity, glue the discharge module on the soup glue directly to the battery. After that, solder the wires to the terminals. You need to take quite thick wires, because the current from the battery is a whole ampere. We insert the wires into the discharge module, solder. And then solder the charging module to it. Please note that all plus sites are connected by a common wire to the plus of the battery, and all minus - with a minus.The charging module can now also be glued to the battery for super glue.
Now the red LED is lit on the discharge module, which means that the module consumes energy with idle mode.
The Internet says that the idle current is 140 micro amperes. Simply put, with a battery capacity of 1200 mAh, this powerbank will discharge itself in about a year. To prevent this, a small switch can be soldered into the gap of the negative wire.
Now carefully wrap the entire powerbank with electrical tape, and then make holes in the electrical tape so that the LEDs of the charging module are visible. It will be much more aesthetically dragging this device into a hefty shrink, but it costs too much.
Now let's charge our baby. We connect it to the USB output of the computer.
A red LED indicates that it is charging. When the battery is fully charged, the green LED will turn on.
Well, now you can charge!
Thank you for watching!
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