How to choose a car battery charger?
Tips for motorists

How to choose a car battery charger?

      The choice of a charger for a car battery sometimes turns into a headache due to the variety of both the batteries themselves and their production technologies, and, directly, the chargers. An error in selection can lead to a significant reduction in battery life. Therefore, in order to make the most appropriate decision, and just out of curiosity, it is useful to know how a battery charger works. We will consider simplified diagrams, trying to abstract from specific terminology.

      How does a battery charger work?

      The essence of the battery charger is that it converts the voltage from a standard 220 V AC network into a DC voltage corresponding to the parameters of the car battery.

      The classic car battery charger consists of two main elements - a transformer and a rectifier. The charger supplies 14,4V DC (not 12V). This voltage value is used to allow current to pass through the battery. For example, if the battery was not completely discharged, then the voltage on it will be 12 V. In this case, it will not be possible to recharge it with a device that will also have 12 V at the output. Therefore, the voltage at the output of the charger should be slightly higher. And it is precisely the value of 14,4 V that is considered optimal. It is not advisable to overestimate the charging voltage even more, as this will significantly reduce the battery life.

      The battery charging process begins when the device has been connected to the battery and to the mains. While the battery is charging, its internal resistance increases and the charging current decreases. When the voltage on the battery approaches 12 V, and the charging current drops to 0 V, this will mean that the charging was successful and you can turn off the charger.

      It is customary to charge batteries with a current, the value of which is 10% of its capacity. For example, if the battery capacity is 100Ah, then the best charging current is 10A, and the charging time will take 10 hours. To speed up the battery charge, the current can be increased, but this is very dangerous and has a negative effect on the battery. In this case, you need to monitor the temperature of the electrolyte very carefully, and if it reaches 45 degrees Celsius, the charging current must immediately be reduced.

      Adjustment of all parameters of the chargers is carried out with the help of control elements (special regulators), which are located on the case of the devices themselves. During charging in the room where it is made, it is necessary to ensure good ventilation, since the electrolyte releases hydrogen, the accumulation of which is very dangerous. Also, when charging, remove the drain plugs from the battery. After all, the gas released by the electrolyte can accumulate under the battery cover and lead to case breaks.

      Types and types of chargers

      Chargers can be classified according to several criteria. Depending on the method used to charge, chargers are:

      1. Those that charge from direct current.
      2. Those that charge from a constant voltage.
      3. Those that charge the combined method.

      Charging from direct current must be carried out at a charge current of 1/10 of the battery capacity. It is able to fully charge the battery, but the process will require control, because during it the electrolyte heats up and can boil, which causes a short circuit and fire in the battery. Such charging should not last more than a day. Constant voltage charging is much safer, but it cannot provide a full battery charge. Therefore, in modern chargers, a combined charging method is used: charging is first carried out from direct current, and then it switches to charging from constant voltage in order to prevent overheating of the electrolyte.

      depending on the features of work and design, memory is divided into two types:

      1. Transformer. Devices in which a transformer is connected together with the rectifier. They are reliable and efficient, but very bulky (they have large overall dimensions and noticeable weight).
      2. Pulse. The main element of such devices is a voltage converter operating at high frequencies. This is the same transformer, but much smaller and lighter than transformer chargers. In addition, most processes are automated for pulse devices, which greatly simplifies their management.

      В depending on destination There are two types of chargers:

      1. Charging and starting. Charges the car battery from an existing power source.
      2. Chargers and launchers. They are able not only to charge the battery from the mains, but also to start the engine when it is discharged. These devices are more versatile and can deliver 100 volts or more if you need to quickly charge the battery without an additional source of electrical current.

      How to choose a battery charger?

      Decide on the parameters ZU. Before buying, you need to understand which memory is suitable for your car battery. Different chargers produce different current ratings and can work with voltages of 12/24 V. You should understand what parameters are needed to work with a particular battery. To do this, read the instructions for the battery or look for information about it on the case. If in doubt, you can take a picture of the battery and show it to the seller in the store - this will help you not to make a mistake when choosing.

      Choose the right amount of charging current. If the charger is constantly working at the limit of its capabilities, this will reduce its useful life. It is best to choose a charger with a small margin of charging current. Also, if you later decide to buy a new battery with a higher capacity, you won't have to buy a new charger.

      Buy ROM instead of memory. Starter chargers combine two functions - charging the battery and starting the car engine.

      Check for additional features. The ROM may have additional charging modes. For example, working with batteries for 12 and 24 V. It is best if the device has both modes. Among the modes, one can also single out fast charging, which allows you to partially charge the battery in a short period of time. A useful feature would be automatic battery charging. In this case, you do not have to control the output current or voltage - the device will do it for you.

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