Automatic ni-mh battery charger can make by yourself

A nickel-metal hydride battery, also known as NiMH, is a secondary cell.They are used in cameras and other electronic devices. They are widely used Because it’s cheap and has a flow rate capacity of the cells to be used as required. Can replace the generic battery immediately.

Important. Can bring to new charging hundreds to thousands of times. Make savings in the long run. and also help maintain the the environment.

Though we will generally choose to buy battery charger. Which is both fast and slow charging. Based on the budget, there, which is most expensive. We should build it up by yourself, because it’s cheap and good quality.

The project is the Ni-MH battery charger on automatically shut off when fully charged. Can charge the batteries from 1-10 pcs. Depending on the input voltage.

In circuit has LED indicator are 2 LEDs. By showing the charging status and will be off when the battery is fully charged.
And the LED function indicator that the battery is connected correctly.

For input voltage is supplied to the charger circuit can be used for the power supply ranging from 12-16 volts and use current to charge to 800 milliamperes.

Operation of the circuit.

From the circuit in Figure 1. When connects the battery into both point P3 and P4. There is LED2 will glow In the event of connecting correctly of all battery. If battery reverse polarity, this LED2 go out, We need to check the battery correctly.

Some voltage from the battery is compared to the voltage at IC1-TL072. Which the TL072 is determined to compare the voltage between pin 2 and pin 3.

Figure 1 Automatic ni-mh battery charger using TL072

In case the voltage from battery to charge each cell is still low. The output from pin 1 of IC1-TL072 will send to a transistor Q1, Which acts as switch on-off working to transistor-Q2 so the current can flow to the battery.
And when the circuit is charging there LED1 will show the charging status.

When the battery is full, its the voltage is compared at the IC1, will make an output at pin 1 of IC1 go to stop working of Q1-transistor, then also causes the Q2-transistor stop.

The end of battery charging, and LED1 indicator charging is off, to display that the battery is full enough.

The Amount of current in charging battery of the project is determined at 800mA. By there is R7-resistor is a current limiter as above.

The S1-switch is pushed for starting charging, in the event that the battery correctly. But not available charging so we can push it to recharging again. To test that this battery has Fully charged.

How to builds this project.

This project have a few components so easy to build. First make the single-sided PCB layout as Figure 2 or can also use easily the Universal PCB Board. Then assemble all parts on the PCB as Figure 3 Which We recommend detailed only because they think you can create your own.

Figure 2 The single-sided PCB layout of Automatic ni-mh battery charger.

Figure 3 The Component layout for the PCB.

The Detail Components
Q1______BC327__ 50V 800mA PNP Transistor ___________= 1 pcs.
Q2__________MJE2955___50V 3A PNP Transistor_________= 1 pcs
D1,D4______1N4148_____75V 150mA Diodes____________ = 2 pcs.
D2,D3______1N4001_____50V 1A Diodes_______________ = 2 pcs.
Electrolytic capacitors
C1,C4______1000uF 25V Electrolytic capacitors___________ = 2 pcs.
C5_____1uF 50V Electrolytic capacitors__________________= 1 pcs.
C2,C3______0.1uF 100uF polyester capacitors_____________ = 2 pcs.
1/4 watts 1% Resistors
R1_________10K_______________= 1 pcs.
R2_________1M_______________= 1 pcs.
R3,R9_______1K_______________= 1 pcs.
R4_________ 470 ohms__________= 1 pcs.
R5_________ 150 ohms 2 watts____= 1 pcs.
R6, R8______100K______________ = 2 pcs.
R7___________1 ohms 2 watts_____= 1 pcs.
You buy them at

Other circuits are recommended.

(with pcb)

  1. Make solar aa battery charger by TL497
  2. Stabised Current Battery Charger by LM723
  3. Nicad Battery Charger by IC LM317T
  4. Simple Ni-cad battery charger with little parts

14 thoughts on “Automatic ni-mh battery charger can make by yourself”

  1. Hi, it possible to put USB at P1 and can I replace IC1-TL072 to IC LM317.. plus can I add solar panel to this circuit?

  2. No you cannot use USB port. Voltage only 5V.
    LM317 is a regulator – TL072 is an Opamp. Two different components altogether, so you cannot do this. Yes you can put a 12V solar panel on input.

  3. Is it for 9v battery? If not than what corrections I should do in it to make it work fpr 9v rechargable battery?

  4. hi, may i know what kind of switch was u used? is’t relay ? and can this circuit charging 9v of battery ? tq =)

  5. can I place only one cell of 1.2 volt 2800mAh for charging/ any changes in ckt for same automatic working?
    for more then one cell charging, connection parallel or series of cells?
    thanks in advance :)

  6. Hello,

    Thanks for the circuit!

    I need to charge a pack with 7x 1.2V NiMH batteries (8.4v totally) and it’s a soldered package, so I cannot charge each cell individually.

    Is this charger able to charge this battery package?

    Thank you,
    Rodrigo Wantuk

  7. I like the circuit and could have a use for it. My question is how many cells can be charged at on time? I have a 6 cell pak that I need to charge. All cells are in series and cannot be separated. Thanks much for the help.

  8. Great circuit; however, I am confused about how to use the charger correctly – please clarify the statement below from the above project description.

    “The project is the Ni-MH battery charger on automatically shut off when fully charged. Can charge the batteries from 1-10 pcs. Depending on the input voltage.”

    Does this statement mean that a variable power supply must be used?

    If the above statement is true then, the variable power supply output voltage should be adjusted between 12-16V to be able charge Ni-MH battery packs with a voltage range of 1.2 (1 AA battery) to 12V (10 AA batteries). Correct?

    Thank you for clarifying how to use this project correctly.

  9. Circuit subject – Automatic ni-mh battery charger can make by yourself —

    After more research I determined that a variable power supply that can provide a range of voltages from ~3.15V to 18V is needed.

    This range was determined by adding ~1.65V (voltage needed to charge 1 AA NiMH battery)to the ~1.5V needed to operate the charger circuit, which is ~3.5V then multiplying 3.5V by the range of cells that may be charged (1-10 cells).

    With this in mind I have decide to build a variable power supply based on the LM317. Then put both circuits in one project box with a selector switch and presto – a combo variable power supply and NiMh battery charger.

  10. Hello i build this circuit.At the moment it works in the part the the green led glows when i connect 1 battery.I input 12v as you clarify .The charge starts when i press button,red light glows and in my multimetr shows 880ma of current that flow in the battery.My problem is that charge does not stop .Battery is burning hot and still red led does not go off still charges.I am assuming that if i let it go it will explode.I tried with 2 batteries in series some effect what could be wrong please?should i lower the input voltage ?The reason i built this charger is for charging 6 cells of1.2 in series.Will this work without mod?

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