DIY do it yourself
Master classes, instructions, useful tips, recipes.
» » »Charger for battery from laptop power supply
Charger for battery from laptop power supply

The network has repeatedly hosted options for using a laptop adapter as a charger for a car and other batteries, using a lamp as a load resistance.
You can, of course, and so, but it’s much more convenient, using not very complicated refinement, to charge the batteries without any lamps. To do this, you do not even need to be an advanced radio master, but just be able to use a soldering iron and a multimeter.

We will need:


  • the power supply itself,
  • 25-40 watt soldering iron with a thin tip,
  • variable resistor 18-22 kOhm,
  • multimeter
  • several resistors with a resistance of 10; one; 2; 3 kOhm.,
  • thin soft wiring.

Attentiveness and some patience will not be superfluous.

Making a charger from a laptop power supply


In our "computerized" time, few people did not have the ancient one lying around, maybe not a working laptop for a long time. If not with you, so with friends. By the way, the older the product, the easier.
We take the power supply (adapter) from it and look for a sticker or inscription on it directly on the case. The one with an output current of 3.5 - 4.5 Amperes is suitable for us.
Charger for battery from laptop power supply

Using a flat screwdriver, disassemble the housing along the gluing line.
CAUTION! The body is glued very tightly. And it’s not worth breaking, and it’s not advisable to get hurt from a torn screwdriver.
You get something like this:
Charger for battery from laptop power supply

We release the power supply board from the screen.
Charger for battery from laptop power supply

Desoldering, if necessary ... on this board is marked in red.
Charger for battery from laptop power supply

Next, we are looking for a place to solder the output wire on the board, it is located on the opposite side of the network connector.
Not far from this place, as a rule, is a small "octopus" microcircuit.
Charger for battery from laptop power supply

We find her foot number 6 and carefully monitor the track to the nearest smd resistor.
Charger for battery from laptop power supply

Knowing its face value is, in principle, not necessary. We don’t need it anyway and will be deleted.
Next, we take a variable resistor with a resistance of 18-20 kOhm.
Gently unsoldering the smd resistor, in its place we solder with a thin soft wiring, a variable resistor.
Charger for battery from laptop power supply

We put its engine in the middle position.
After all these manipulations, we connect the network cable, plug it into the outlet, and do not forget about CAUTION. Still - near 220 Volts. Fights ... if you do not respect him.
The probes of the multimeter included in the measurement of the “constant” are connected to the low-voltage connector of the unit (the one that should be inserted into the laptop).
Slowly we rotate the resistor engine, we achieve on the multimeter display indications of 14 with a small, volt. We don’t touch the engine anymore.
We disconnect everything from the network, carefully so as not to stain the solder adjacent to the place of soldering parts and not to knock down the set position of the "variable", we unsolder the wiring from the board.
We measure the resistance of the variable resistor in the position you fixed.
For different blocks, it can be different. From the resistors you have, we select by connecting in series the value that the multimeter showed.
For example, 10 + 3 or +5 kOhm.
We solder the resistor in this way, we put it in place so that there is no contact with other parts. If necessary, isolate or output wires outside the board.
Once again, check the voltage, for quality soldering.
If everything is fine, we assemble the block by gluing it in half with a “Chinese nozzle” (hot glue) or a hot soldering iron.
I got it like this:
Charger for battery from laptop power supply

However, for better control, I also installed an ammeter (which was).
Securing it to the case with an ordinary clamp.
Charger for battery from laptop power supply

This is how the charging process looks.
Charger for battery from laptop power supply

Such voltage and amperage, solely because the battery that I use for the paralet is fully charged.
We tried to recharge the battery from the car. It copes without problems.
Why recharge? Because the charging current of a strongly discharged battery will obviously be more than three and a half amperes, which means that the unit will simply go into defense as if it were a short circuit, which, incidentally, is not afraid of.
Hope the information was helpful.
come back
Comments (28)
  1. Igor Ryzhev
    #1 Igor Ryzhev Guests February 9, 2019 7:32 p.m.
    5
    what is the chip? What are 14 volts? Batteries are charged with current, not voltage. Why not leave variable resistance? This is just to stir up the battery.
    1. Vladimir Lukyanov
      #2 Vladimir Lukyanov Visitors February 11, 2019 11:19 p.m.
      0
      This is a so-called microcircuit. power driver, you can leave the variable one and adjust the output voltage to the voltage, the author gave advice on how to remake from 19v to 14v.
  2. Goncharov Alexander Yuryevich
    #3 Goncharov Alexander Yuryevich Guests February 9, 2019 8:11 p.m.
    0
    I saw a lot of tips for remaking power supplies, but for the first time so that it is so simple and accessible about such a delicate thing. Many thanks to the author! I could not find fault with anything. It would be useful to supplement the name of the chip, I'm sure there are options on the market for units with a different pinout of the chip. Thank.
    1. Kiteblack
      #4 Kiteblack Guests March 7, 2019 03:53 a.m.
      1
      You, first, familiarize yourself with the battery charging modes, and only then admire. And do not try to repeat - ditch both the battery and the power supply. If you break google - Batteries (all without exception) are charged with current, and a certain value. In lead it is 0.1C. Those. battery, with a capacity of 60Ah, it is recommended to charge with a current of 6A. Here is a voltage stabilizer, and with protection against short circuit and overloads (if you are lucky, then, when connected to a discharged battery, it will simply go into protection, if you are not lucky, the key transistor will fly out with a whistle). Before sharing "clever thoughts", the author would not hurt to go to a "circle of crazy legs" for at least a couple of days ...
  3. Semen
    #5 Semen Guests February 9, 2019 11:15 p.m.
    0
    In vain the ammeter set. It was necessary to put an aperture.
    1. Vladimir Lukyanov
      #6 Vladimir Lukyanov Visitors February 11, 2019 11:24 PM
      0
      Learn materiel
      Ammeter (from amps + μετρέω “measure”) - a device for measuring amperage.
  4. Guest Vladimir
    #7 Guest Vladimir Guests 10 February 2019 01:26
    4
    I would leave a variable resistor, and by adjusting the output voltage it would be possible to limit the charge current without going off to protect
  5. Guest Alex
    #8 Guest Alex Guests February 10, 2019 04:42
    2
    Greetings, if you calculate the power of the unmodified 20 * 3.5 = 70 watts, now we will deduce the current of the converted 70 \ 14 = 5 Amperes, so that it will cope with the car) all the more, the majority of the old s \ y had a current of 4.5A, and this is already 6.5A after alteration.
  6. Guest Michael
    #9 Guest Michael Guests February 10, 2019 08:43
    1
    That's how many times I already see “We take a variable resistor and rotate it, and then take readings from it ...” - I screwed up this way so many times - for this method you only need a wire-type resistor, or rather an attenuator - this is the so-called , step or discrete resistor, which you can assemble the desired value from the resistors of lower resistance. The attenuator is preferable, and on it to perform the selection of the desired parameter of the tested device, and for one and get, automatically, the required parameter. Which is possible to apply in the required design.
  7. also a doctor
    #10 also a doctor Guests February 10, 2019 1:56 p.m.
    0
    The population of old system engineers with power supplies is much larger. Are there any power supply outputs with the necessary voltage?
    1. Guest Michael
      #11 Guest Michael Guests February 11, 2019 11:28
      0
      No, there are high amperes 12, 5, and 3.3. volts. You can charge it, but you won’t be able to fully charge it. Without alteration, you can power 12 V screwdrivers. You can even 14, but the speed will be less.
      1. Vladimir Lukyanov
        #12 Vladimir Lukyanov Visitors February 11, 2019 11:21 p.m.
        0
        What are you saying?)
        High amp outputs due to what implemented?)
        The power circuit + transformers, which are exactly the same as here (by the way they are essentially identical) are controlled by the driver.
        And in computer PSU, this method is also perfectly applied by setting the voltage by changing the value of the resistor. It’s just that there is mikruha on 16 legs, but there is no problem finding a datasheet on them
  8. Sergey S.
    #13 Sergey S. Visitors February 10, 2019 4:44 p.m.
    0
    He made many different artisanal chargers. For such as in the picture, I suggest indiscriminately block.
    In series with battery 2, two incandescent bulbs, the first took 26 volts 20 watts, the charge current
    400-500 ma. the second at the end of the charge 26 volts 5 watts, current 80-100 mA.
    Monitor only the voltage, not more than 15 volts on the battery.
  9. Gregory
    #14 Gregory Guests February 11, 2019 07:37
    1
    The power supply from a samsung laptop of 14 volts without alterations gives a current of 3 A on the AKB-55
    1. Vladimir Lukyanov
      #15 Vladimir Lukyanov Visitors February 11, 2019 11:23 p.m.
      2
      The article indicates how to remake 19c in 14c. Why koment about 14 volt block?)
  10. Guest Victor
    #16 Guest Victor Guests February 11, 2019 18:32
    0
    ... Yes, everything turned out fine and works ... Only hands breaks ... Infection ...
  11. alex
    #17 alex Guests February 11, 2019 8:15 p.m.
    0
    do the charging for the car battery from recharging the phone ... urgently at 62am / h
  12. Guest Victor
    #18 Guest Victor Guests February 11, 2019 11:23 p.m.
    1
    The simplest thing is to consistently put up resistance!
  13. Vyacheslav
    #19 Vyacheslav Guests February 13, 2019 08:08
    1
    There is a power supply from the camcorder: 8.4v 1.5A. Can I use it to charge a 12v battery?
  14. igor
    #20 igor Guests 13 february 2019 09:06
    0
    It is possible and automobile through a 21vat bulb.
  15. Guest Victor
    #21 Guest Victor Guests February 13, 2019 12:53
    0
    Well, the red arrow is not the 6th leg in the photo.
  16. Alexander.
    #22 Alexander. Guests February 13, 2019 5:31 p.m.
    1
    I would be ashamed to publish such a self-made dog. Find the circuit of your PSU, datasheet on the “6-foot microcircuit”, taste the principle of PWM operation, figure out what changes you need to make to the circuit, check it in practice, and only then advise others.
    1. Anastasis
      #23 Anastasis Guests February 19, 2019 19:16
      0
      at least he did something and shared ,? You are constrained. A author well done thank him
  17. Leonid
    #24 Leonid Guests March 5, 2019 4:41 p.m.
    0
    Could be so. But in developing the topic, I implemented another option. You need a laptop power supply of 19 volts, 4.5 A. A DC-DC converter lowering 9A with voltage and current adjustment, an indication module 0-100V, 0-10A digital, a charge monitoring module XH-M601. All. Without altering the voltage of the PSU, we lower the DC-DC module to the level of 15V, set the current limit level to 4-4.5A on it and charge the battery with this stabilized current. The display module shows the voltage on the battery and the charging current. The charge control module will disconnect via the charger network when the voltage at the terminals of the 15V battery is reached. Modules are finished inexpensive products from the online store.
  18. Kiteblack
    #25 Kiteblack Guests March 7, 2019 03:41 a.m.
    0
    Afftar, please name at least one type of battery that is charged with voltage?
    I can’t put a deuce - just a count! Bold, uncouth, count ...
    1. Leonid
      #26 Leonid Guests March 7, 2019 07:46 a.m.
      0
      You need to read carefully and all the letters that are written. Maybe you will understand something.
  19. Sergey K
    #27 Sergey K Visitors April 23, 2019 6:47 p.m.
    0
    After the alteration, a stable voltage of 14V is obtained? Not an ice, at the end of charging there will be a very small charging current, in my opinion it is much better to make a charger from such a power supply by supplementing it with a current stabilizer on the LM1084 chip without touching the power supply itself. Well, supplement with a Chinese amp-voltmeter to control current and voltage.
    1. Guest Roman
      #28 Guest Roman Guests April 24, 2019 2:57 p.m.
      0
      You think wrong. Not a single charger in the world is capable of delivering a large charging current, while increasing the battery’s own EMF, approaching the charger EMF. The decrease in current at the end of charging is Ohm's law.

Read also

Error codes for washing machines