Probably every motorist faced with the problem of a discharged battery. Sometimes the battery is discharged in the most unexpected situations, for example, when the driver is going to work and is in a hurry so as not to be late. At such moments, a discharged battery can lead to not very pleasant consequences.
In order to avoid such situations, many motorists resort to using special devices that are allowed to charge the car battery. Such chargers can be easily purchased in specialty stores or markets. The range is wide, the prices are different.
But many motorists at least once thought about making a charger for their own batteries. But such an opportunity really exists. In fact, each user can assemble such a device on their own, spending only on the components of the entire device. In addition, using all the necessary schemes and instructions for this, any motorist can manufacture a charger. for a car battery with your own hands, especially if he already has some experience with electrical engineering.
1 A simple charger on the LM317 chip
- 1.1 Scheme
2 Powerful battery charger
- 2.1 Scheme
3 Impulse Battery Charger
- 3.1 Scheme
A simple charger on the LM317 chip
For starters, you can imagine the option of creating devices on the chip LM137, which is a linear voltage regulator, capable of adjusting the output voltage. This option may be called one of the simplest, since the device itself is not a complicated self-made charging device, which allows the user to make it without any special problems.
In this embodiment, the device will involve as many as two stabilizers. This is done in order for one of these two stabilizers to be connected according to the current regulator circuit, while on the second a threshold node must be assembled.
Above is a diagram of such a charger. On it you can see that R2 and R3 resistorsWith the help of which you can set the required output voltage to the user, replaced here with a variable resistor. This is done for more convenient adjustment. The battery charge will be completed at the exact moment when the voltage on the battery itself is equal to the charge voltage of the device.
The maximum allowable current charge is 1.5 Amps. Despite the seeming weakness, this value of the charger is enough to charge the batteries. The resulting device can be charged bespereboyniki, batteries for motorcycles and cars. In the case of the latter, the charging process will be very long, but it must be admitted that the variant of such a self-made charger is a very working one and can certainly come in handy.
In the event that the current from the charger is more than 500 mAthen the microcircuit is recommended to be installed on the heat sink.
Powerful battery charger
Above was a very simple version of an improvised car charger for a car battery, weak but permissible. Now there will be a version of one of the most powerful devices that you can do with your own hands. The current of such a device will be equal to 50 Amps, and the output power - 350-600 watts on average.
The scheme of such a device is very simple. The basis is taken by all known IR253, which will serve as the master oscillator. She will manage two power switches. It is recommended to use powerful N-channel field voltage transistors.
As you can see, the block diagram is a half bridge. The mains voltage is fed to the rectifier through a mains filter. To limit the starting current, a thermistor is used, having a rated current of 5 Amps and a resistance of 5 Ohms. Film capacitors and choke serve as a network filter for smoothing noise and network ripples.
As a bridge rectifier, you can take a ready-made bridge, but at the same time you can assemble it from four separate diodes. In both these cases, the bridge must be rated for a current of 6-10 and a voltage of 600-1000 volts (recommended values). For this, it will be very convenient to use ready-made diode assemblies that are already available in computer power supplies.
Electrolytes half bridge have effective capacity 330-470 uF and operating voltage of 200-250 volts. If the power of the block is higher than the allowable values, then the capacity should be increased of the above-mentioned capacitors, which, by the way, can also be found in the power supplies of personal computers. There you can also find a ready-made transformer that will not need rewinding.
Power transistors can be installed either on a common heat sink, or on individual ones. By the way, if the user decides to connect the power transistors to the common heat sink, then you have to pre-isolate his keys in order to avoid the likelihood of a short closure
During assembly, the microcircuit is recommended to be installed on a special platform. This is done for easy replacement of microcircuits in the event that it suddenly fails. The device will not be affected by voltage drops in the network, which guarantees its stable operation without any failures and noises.
It should be remembered that moment in idle mode transistors must be cold, even icy. Otherwise, this may indicate an error in the installation or some component of the assembly does not work.
It is recommended to use fast, pulsed or ultra-fast as a diode rectifier at the output of the device. high current diodes (these are 30 amps), you can also use schottky diode assemblies working on large power. In the case of this device, it is better not to use conventional 50 Hz rectifiers, since the output of the circuit has a high frequency voltage.
- Attention should be paid to the fact that this unit is not equipped with protection against possible short circuits, therefore, do not close the wires at the output, otherwise the circuit may malfunction and exit from building.
The whole scheme is quite compact and easy, which can please not the most experienced users who do not have certain skills and much experience in this matter. Having a scheme can help in this matter.
Impulse Battery Charger
You can consider the option of manufacturing a pulsed charger. The principle of creating such a device is that you simply need to replace the transformer power supply with a pulsed one. This is a fairly compact and lightweight charger, which will be discussed in detail below. The switching power supply is manufactured using IR2153 chips.
This circuit differs from its other counterparts in that in this case, instead of two capacitors, which are connected with a midpoint, only one electrolyte is used after the diode bridge.
This version of the charger is designed for relatively small power, which in principle can be corrected if you replace some components with more powerful ones. As a result, you can create a more powerful device.
In this scheme, keys of the 8N50 series can be used. These keys are equipped with an insulated housing, so in the case of a common heat sink, you can not worry about mica gaskets, as they can not be used at all.
Diode bridges, again, can be taken from the power supply from ordinary personal computers, and you can collect it from their four rectifier diodes.
Then you can mention the power supply circuit chips. Power can be taken from the break, resistor for current suppression by 18 kΩ. After the resistor is a simple rectifier on a single diode and the power is fed immediately to the chip. The power supply also contains an electrolyte with a parallel-connected ceramic or film capacitor, which is done to better smooth out noise and ripple.
- By the way, the power transformer can also be taken from the computer power supply. It is just perfect for such purposes, as it provides a decent output current and provides several output voltages at once.
Output rectifier diodes must be pulsed, as the usual will not be able to work due to the increased frequency. A mains filter can be omitted, although a pair of tanks and a choke, which is a filter, are desirable for installation. You can use an ohm thermistor by 5 to easily reduce inrush from the input to the filter; you can easily pull it out of a computer power supply.
Electrolytic capacitor is selected taking into account special ratio 1 watt - 1 microfarad. The voltage of such a capacitor should be 400 volts.
This is a fairly simple scheme that can be performed even by a user with no experience. In addition, if you have the necessary schemes and tips to create such a device, you can cope without any problems.