Radio designer 3 in 1 or how I did reserve charging with a USB output on 5 volts.

I decided to collect a good backup charge. In this review I will try to describe how I did it and what I did.
ATTENTION!!! If you do not have experience with lithium batteries, it is better to find instructions for their use, otherwise there may be dire consequences, up to the explosion of the batteries !!!

To collect such a charge of one stabilizer is not enough, you need more batteries (I used lithium 18650), and you still need to charge them and bought more for the batteries such a charge.
I received all 3 devices with a difference of 2-3 days and everything was well and securely packed.
Used materials:
1. Voltage stabilizer - bought on aliexpress for $ 2.47 + $ 3.20 shipping, totaling $ 5.78
2. 6 batteries 18650 - purchased on an IIC for $ 21.57 (set) - 15% discount
3. Charger for 18650 batteries - purchased on BIC for $ 8.48 - 15% discount.
4. Connectors, wire, foil glass fiber - bought everything in an offline store for 200 rubles.
5. Straight arms - from 0 to 1000 rubles.
Device Specifications:
Voltage 3.7 volts with a declared capacity of 4000 mAh (most likely there is no such capacity)
The output voltage is 4.2 volts and a current of 900 mAh (the voltage of my multimeter gave 4.14 volts).

Voltage regulator:
Input voltage declared 1-5 volts, actually stops working after reducing the battery charge to 3.13 volts, and this is very good, it will not completely land the lithium batteries.
Output voltage of 5 volts and 1 amp, no currentI checked, but it seems to be true, the devices charge quickly and if you use a Chinese thin cable to connect the battery and the stabilizer, they will begin to heat up and burn, so you need to use wires with a large cross section.
The hull did so temporarily until a suitable hull was found, which I have so far made of foil fiberglass.
It turned out such a miracle:

Used 6 batteries connected fromat the same time, but for starters, I equaled their potentials (whoever is interested, will find the information necessary for this in the internet). To begin with, I decided to check how much is enough and whether the stabilizer from 1 battery will work at all (this is only about 18650 batteries). Oddly enough, everything worked fine, but not for long.
Then I picked up another 1 and tried from scratch (fully discharged) to charge the tablet, the batteries were enough for 70% of the charge.
Next was a check done with 4 batteries,The tablet charged 100%, also charged the almost completely discharged tablet and it charged 100%, then charged another tablet, but I didn’t completely discharge it.
Now I have connected all 6 batteries and I am still conducting tests, but as long as I like the result, when I discharge completely, I will write here how much 6 batteries were enough for me.
Charging had to be refined, or rather soldered to it connector for charging batteries.

On the stabilizer there is a blue LED that indicates the charge, when it goes off, it means the battery is discharged, if it is dim, the device that has been charged has already been charged or is not connected.
So, finally, I discharged it))) Enough for 3Fully charge the tablet, charge the bluetooth headset, 2 times the communicator and 1 time the usual phone, the indicator is not bad. Now I will do a battery charge test)))
Device turned off:

Enabled device:


I want to add that the stabilizer is very small (only 20 × 25 mm.)

The battery compartment turned out like this:

Well, a couple of photos:

It is expensive all this assembly, but if you believeChinese ampere hours of batteries, it turns out I got a backup charge of 24000 mAh, I think of course it will be less, but still if the tablet is fully charged at least 2 times, then it will be great, the test will show. Of course, the weight of the device is not small, 500-700 grams, but this is nothing.
In general, a decent device turned out, Icompletely satisfied. I wish he would have another discharge indicator that would show how many percent of the charge remained, but I think I will find something Chinese, but this is in the future.
And finally, the video:
P.S. Do not scold much for the design of the case, of me the designer is very bad, and the case is made temporarily until I find a suitable case.