A simple automatic key, in addition to the main function: automatic shutdown when fully charged, also has the function of starting and stopping the cycle using clock buttons.
The circuit is connected between the charger and the battery. Can be easily adjusted to any control voltage between 6-24 V.
Will need
- Stabilizer TL431 - http://alii.pub/5mclsi
- Transistor IRFZ44N - http://alii.pub/5ct567
- Multi-turn potentiometer 10 kOhm - http://alii.pub/5o27v2
- Tact buttons - http://alii.pub/5nnu8o
- LEDs - http://alii.pub/5lag4f
- Resistors 1.5 kOhm; 1 kOhm; 15 kOhm - http://alii.pub/5h6ouv
Scheme
The circuit consists of two main components: the first is an adjustable threshold stabilizer assembled on a TL431 chip and the second is a switch on an IRFZ44N transistor.
The principle of operation is simple: as soon as the voltage reaches the set value, the stabilizer will close the switch and the flow of charging current will stop.
Making a key for charging batteries
The automatic key circuit will be assembled using a hinged installation. Thick strands of copper wire are used as power buses.We fix one wire and begin the assembly by soldering a 1 kOhm resistor. We first trim the long output elements.
Solder the stabilizer chip. Pinout in the photo.
Solder the adjustable divider circuit.
Add a “negative” power bus.
Solder Light-emitting diode and a resistor.
Next button and more Light-emitting diode with resistor.
Solder the transistor. Pinout in the photo.
All that remains is to solder the button and a powerful diode.
The circuit is ready for use.
Turning on and testing the charger
Instead of a battery, temporarily connect an incandescent lamp to the output. By rotating the variable resistor slider, we will ensure that the lamp goes out when the voltage exceeds 14.3 - 14.4 V (Full charge voltage for acid batteries).
Now let's connect the battery. The buttons can be used to start or stop the charging cycle.
When the voltage reaches above 14.4 V, the device will disconnect the battery from the charger.
At this point the work process is completed, the barathea is fully charged.
Watch the video
How to make a balancing unit using transistors for any number of lithium-ion batteries - https://enn.washerhouse.com/7518-kak-na-tranzistorah-sdelat-blok-balansirovki-na-ljuboe-kolichestvo-litij-ionnyh-akkumuljatorov.html
