1 idea for using batteries from old mobile phones

Electronics 76 126 11

An old cell phone battery can still serve you well and be useful. The battery itself may no longer be charged due to the past years, but it has one useful thing that will more than last for many more years.

The fact is that the batteries of almost all mobile devices are equipped with a built-in charging controller. This is a small board located in close proximity to the battery, controlling not only charging, but also discharging, preventing the critical voltage from being underestimated. In addition, this small scarf protects the battery from short circuits. And some models also have a temperature sensor that monitors the operating temperature.

So, you can easily get this useful controller and use it for your 3.7 V lithium-ion batteries, say, the 18650 series - http://alii.pub/5becfz

Idea for using old cell phone batteries

We take the battery from an old mobile phone and carefully try to lift the upper plastic part.

Then we crawl up with wire cutters and bite off the flat lamellas coming from the battery.

Next, all that remains is to remove the board from the plastic protection.

Here is the charging controller itself.

On the sides there are areas for connecting the battery, marked with the symbols “B+” and “B-”. On the reverse side there are 3 pins for connecting to the phone. The two side ones are usually the way out.

We solder the wires to the controller going to the battery.

Then we solder a battery to the controller, consisting of 3 18650 batteries connected in parallel.

Solder the wires to the controller output.

We apply 5 V to the input and charge the battery.

As soon as the battery is fully charged, the controller opens the circuit.

Next, power can be taken from the controller output.

Watch the video

How to make a simple Power Bank 5000 mAh in a syringe case - https://enn.washerhouse.com/7433-kak-sdelat-prostoj-power-bank-5000-ma-ch-v-korpuse-iz-shprica.html

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Comments (11)

#1 Yuri_ Visitors 22 March 2021 18:31
14

The board in question is a protection module, but in no way a charge controller!
That's why:
So, you can easily get this useful controller and use it for your 3.7 V lithium-ion batteries, say, the 18650 series
- advice is frankly sabotage.

And even as protection, this scarf can only be used with a full understanding of where it can be used and where not, otherwise you can recharge it before the fire.
- Answer
1. #2 Yuri_ Visitors March 23, 2021 00:47
  12
  
  Although, on the other hand, if a person charges batteries by connecting them in parallel, then no controller will help him.
  
  Answer
  1. #3 Sergey K Visitors March 23, 2021 01:46
    1
    
    Why is this kind of charging not suitable for you? This is quite a standard method; it cannot be charged sequentially. And in parallel - as much as you like and you can even install different capacities, but different capacities and even a balancing board does not help, well, except that the capacity differs by a couple of percent...
    
    Answer
    1. #4 Yuri_ Visitors 23 March 2021 16:49
      3
      
      When charging a battery, it is important to regulate the amount of current passing through it. This is what the charge controller basically does.
      
      Now let’s imagine such an extreme case: we have 20 batteries, about which we know that they require a charge current of 5 amperes. We connect them in parallel, connect them to a 100 A charger, and start charging.
      But we don’t know that of these 20 batteries, 19 have a very high internal resistance, and the twentieth, on the contrary, has almost a short circuit inside.
      What will happen? That's right, almost all 100 A will go through one battery, and the charger won't even move to stop this mess.
      
      And when batteries are connected in series, the current flows through all batteries exactly the same.
      
      Answer
      1. #5 Sergey K Visitors 24 March 2021 16:39
        0
        
        Well, thanks for explaining, now run urgently to get a patent, otherwise the whole world is already tired of creating chargers for serial batteries with balancers ;) Well, and at the same time equalize the charge by connecting banks in parallel.
        No, of course, strictly speaking, charging the elements separately is not a bad idea; at the same time, you can select them by capacity and reject defective ones. But in fact, a short circuit in lithium cells is a much rarer phenomenon than loss of capacity. I've never seen one in my life. In lead ones, yes, they often short out...
        
        Answer
        
        #6 Yuri_ Visitors 25 March 2021 02:27
        2
        
        the whole world is already tired of creating chargers for series batteries with balancers
        But for some reason, in all the chargers for AA batteries that came into my hands, they (the batteries) were not paralleled, but were controlled individually.
        
        in fact, a short circuit in lithium cells is a much rarer phenomenon than loss of capacity
        My words about short circuits should not have been taken literally (I even made a postscript on purpose).
        But different types of batteries have different internal resistance, and as the batteries age, it increases in them, and also in different ways. And we get a battery from cans with different resistances. And in addition to this, there is a problem typical for electronics, when in order to increase the current passed, the power parts are paralleled, but their resistance is different, and through the one with less it, a larger current begins to flow than through the others. Because of this, it heats up more than others, due to heating its resistance decreases, as a result of which even more current begins to flow through it - and so on until it flares up.
        In batteries, resistance is also inversely proportional to temperature.
        
        Answer
      2. #7 SERGEY ISOV Guests 30 April 2021 16:43
        1
        
        In parallel, you can connect and charge any batteries with the same chemistry. the voltage across them will be the same and the currents will be distributed according to the internal resistance.6th grade. although you don't understand. the board will cut them off at the same overall voltage.
        
        Answer
        
        #8 Yuri_ Visitors 1 May 2021 17:04
        0
        
        and the currents will be distributed according to the internal resistance
        
        Everything is correct - they will be distributed according to internal resistance. But this resistance is not constant, it changes during the charging process depending on the temperature. Moreover, the TCS is negative. I hope you understand what this can lead to.
        
        Answer
    2. #9 Yuri_ Visitors 23 March 2021 16:58
      0
      
      Let me add: “there is almost a short circuit inside” - this is a normal condition for a healthy battery. And the closer its internal resistance is to zero, the better it works.
      
      Answer
2. #10 Valery I. Guests 28 March 2021 19:57
  1
  
  I bought charge-discharge controllers for lithium-ion batteries on ALI, the price was about 25 rubles, with a USB-micro connector, with light indication - well, a very convenient thing.
  
  Answer
#11 Georgich Guests May 15, 2021 11:33
1

Until I see the pattern for this scarf, I won’t even try. With the same success, we can say how to charge CuCumulators from a Chinese garland controller. Moreover, in parallel.
- Answer