DIY power bank supercapacitors

Supercapacitors have tremendous capacitance compared to conventional capacitors. They also have a number of advantages over lithium-ion batteries, such as: they are not afraid of low temperatures, they are not afraid of a complete discharge. All this made me turn the bank on supercapacitors.
Conventional power banks, if they are idle, are discharged over time, since the elements have self-discharge. And one fine day, when you need to take a bank, say, on a hike, it will be "dead" and will not show signs of life.
The same model, made on ionistors, will always be ready for work if you first charge it.

Will need

• 4 supercapacitors (ionistors) at 2.7 V and 500 F.
  
• Controller with LCD and USB 5V 1A, 2.1A.
  

The controller performs several functions at once: it controls charging and discharging the battery, protects against short circuit, and displays the capacity of the entire battery on the display.
Micro USB is used to connect the power supply for charging. The other two USB are outputs for connecting the load.

Making a power bank on ionistors

We solder two supercapacitors in series. Plus to minus.
We also solder the following two. And already these two pairs are soldered in parallel to each other, "plus" to "plus", "minus" to "minus".
The result was a battery of ionistors with a maximum voltage of 5.4 V and a capacity of 1000 Farads.
Solder the controller.
We insert the USB cable and charge our new power bank.
As soon as it’s charged, we connect the phone and check if it is charging.
Yes, everything works fine - the mobile is charging.
To isolate all the contacts and make some kind of case - put on a shrink film and blow all over with a hot air gun.
Under the display, cut a window with a clerical knife.
Side view, USB ports open.

Conclusion

In conclusion, I would like to add a fly in the ointment: ionistors have a large self-discharge compared to lithium-ion batteries, therefore, after a full charge, the time of its use is more limited than that of commercially available devices.