How do I charge the car battery at home?

Sooner or later, drivers have to deal with battery-related problems. Like any device, a battery has a certain life cycle, after which it is time to think about buying a new battery. On a car, it is often not fully charged, so to extend its life, it is necessary to periodically restore the battery using an external source. And sometimes it raises questions - how to charge a car battery at home from a regular household power supply.

General information about battery charging

In principle, an ordinary motorist does not need any special knowledge to work with modern batteries. No wonder they are called unattended. It is enough only to know that the battery is charged from a special device, and to be guided by the instructions for its use.

But as you know, drivers of the people are extremely curious and able to find a way out in any situation. That is why it is worth knowing at least the minimum amount of the basic requirements, the fulfillment of which will ensure the successful charging of the battery. They are simple and there are few of them:

  • For these purposes, a constant voltage source is used. It can be of any form - constant, pulsating, pulse, etc.
  • The current value during charging should not exceed 1/10 of the battery capacity, that is, current is required to charge a 62 Ah battery not more than 6.2 A. A higher value can damage the battery, and a lower value will increase the duration of the process.
  • Charging must be carried out until the voltage on the battery reaches 14.4 V.
  • Special devices must be used to charge the battery. There are many varieties of them, but if you are only interested in the end result, it is best to use automatic ones. They themselves will ensure the maintenance of the desired mode and disconnect the product from the network at the end of the process.

There are other very interesting subtleties associated with the device and operation of the battery, but to restore its performance, it is enough to follow the above requirements. Their implementation will allow you to charge the car battery at home without hassle, without making significant efforts for this.

What if there is no automatic device?

In general, in this case, you can do with your own strength and knowledge. If you have a transformer, on the secondary winding of which there is a voltage of about 15 V, then it is quite possible to assemble a simple charger, for example, such as shown in the figure below.

In this circuit, you can even do without the capacitor C1. A feature of its work will be the possibility of a significant current in the initial moment when the battery is connected, when it is practically discharged. In the future, as the battery is charging, its value will begin to decrease, and when the voltage is equal to that present on the secondary winding of the transformer, the process will stop.

That is, here the mode of automatic disconnection from the network is additionally implemented. There can be many options for constructing such a circuit, the figure below shows another one:

Or another, simpler version, with one diode. In this case, charging will go in pulses of current, the magnitude of which is limited by the light bulb. By selecting it, you can regulate the charging current.

To avoid its excessive increase at the initial moment, it is best to introduce an additional voltage regulator and mode control devices into the circuit, for example, as shown in the figure:

The process parameters are determined by the resistor R *. By changing its value, you can set the desired charging current. And an ammeter and a voltmeter will help control the process itself.

In addition to self-assembly of devices, it is permissible to use powerful external voltage sources, for example, laboratory power supplies. They allow you to get the result no worse than the chargers provide.

For normal operation of the battery, it must be charged periodically, at least once a year, using an external device. There is nothing difficult in this, you just need to choose it correctly, and then everything can go through automatically, without your direct participation.