If you leave your headlights or radio on overnight, the battery in your car will almost certainly run out. To charge a dead battery at home, you can buy or assemble a car charger.
It is necessary
- - computer power supply;
- - 25-volt output capacitors;
- - enamel wire d0, 5-0, 6 mm;
- - resistance 2 W;
- - ammeter;
- - soldering iron;
- - solder;
- - flux and soldering acid.
Instructions
Step 1
Take a computer power supply TX or ATX, check it for operation. Remove the top half of the case and see which chip it is built on. The TL494CN circuits (analogs of KA7500, DBL494, A494, IR3M02, mPC494C, MV3759, M1114EU, etc.) are suitable for us.
Step 2
Remove all outgoing wires from the board, leaving only 2 yellow (12 volts) and 2 black (this is "COM", ground). The ATX power supply unit also has a green wire corresponding to the permission to turn on PS-ON, solder it to the ground. The wires of the fan and the 220 volt network must also be unsoldered.
Step 3
Remove the board from the case and replace the 16-volt output electrolytic capacitors with 25-volt ones. Please note that you should not reduce the capacitance of the capacitors (you can increase it).
Step 4
Look at the tracks of the first output of the microcircuit, cut off all unnecessary elements (by cutting or unsoldering the parts). Attach the variable resistor to the front bead of the case, it will act as an output voltage regulator (set voltage from 3 to 24 volts). If you plan to use the device only for charging a car battery, you can set a constant resistance with a voltage of 14.4 volts.
Step 5
Remove all unnecessary connections 2 and 3 pins of the microcircuit. On the quadruple output, turn off the protections that block the issuance of pulses, leaving the "soft start" function, cut off all unnecessary ones.
Step 6
On the 15th and 16th pins, organize the limitation of the output current so that at any load resistance the current does not exceed a certain value and you are not afraid of short circuits. To do this, make a current sensor in this way: take a two-watt resistance of the MLT type, wind an enamel wire d0, 5-0.6 mm on it, in one row (turn to turn), and solder the ends to the resistance terminals. Instead of a current sensor, you can install a conventional ammeter.
Step 7
Replace the variable resistance with a constant one by setting the maximum charging current. If you plan on charging a 60 amp-hour lead acid battery, set the charging current to 6 amp.
