On modern cars, more and more often, the manufacturer begins to install maintenance-free batteries. There are many recommendations on how to charge a maintenance-free battery, but they are all too sophisticated and an ordinary motorist does not always manage to understand the essence of the battery charging process itself. This publication will consider a simple and at the same time effective way to charge a car maintenance-free battery using an example Bosch silver s4.
Before you begin the charging process, you should immediately determine what age the battery is. Maintenance-free car batteries that recharge or reanimate for more than five years are a waste of time. Even if you manage to do something with him, his work will not be long. It is better to immediately bring old batteries to the recycling department.
And now about the technical aspects of charging. The charger with which you will be charged must work fully automatically, i.e. The charging process must be controlled by the program you choose. This program will be able to control the required charging current itself, as well as provide a constant supply of the desired charging voltage. It is also worthwhile to identify particular care when connecting the charger to the battery terminals. The red terminal is always fixed to, the black terminal to minus. If the terminals are not color-coded, look directly at the sockets of the charger and make the correct connection.
Remember that the battery must be charged in a well-ventilated area, since during this process substances that are harmful to the body are released.
And one more nuance, if you charge only your car’s battery from time to time, then buying the necessary charger is an unreasonable waste of money, because charging a maintenance-free battery in a specialized center will cost you much less than purchasing a device.
Video: How To Charge A Bosch S4 Battery
How to charge a maintenance-free battery. Instruction manual
- We connect, observing the polarity of the battery to the charger
- We set the required charging current. The charge current should correspond to 1/10 of the battery capacity. In our case, we have a maintenance-free Bosch silver S4 battery, the capacity of which is 12 volts 70 A / h and must be charged with a current not exceeding 7 A / h. If the battery is completely discharged, then it is recommended to charge it with the lowest current of about 1-2 A / h.
- Remember that when connecting the battery, the charger must be disconnected.
- After the above operations are done, turn on the charger, set the voltage to 14.5 volts, if there is a voltage regulator, set the current to the minimum value, after which the charging process begins.
- During charging of the battery, the current will decrease, and when the process comes to an end when the voltage at the terminals is 14, 4 volts, the current will correspond to the value of the self-discharge current of the battery. this is approximately 200 mA or 0.2A. Important to remember! If for serviced batteries, the nominal current during charging is 1/10 of the battery capacity, then for maintenance-free batteries, the main indicator during charging is not the current strength, but the voltage.
- I would also like to note that if the battery was completely discharged, its voltage during charging should also be slightly reduced to 12-13 volts. In this case, it is necessary to control that the current strength at the beginning of the process does not exceed 1/20 of the battery capacity. If this value exceeds, reduce the voltage.
Maintenance-free battery information
Maintenance-free batteries should only be charged with automatic chargers. The peculiarity of such batteries is that the degree of charge of the battery at the end of the charge directly depends on the magnitude of the charging voltage that the charger provides. For example, at a voltage of 14, 4 volts, a 12 volt battery can charge approximately 75% in 24 hours. 85% if the voltage is 15 volts at the same time by 85%. 90%, and at a voltage of 16 volts. by 95%. 97%.
It turns out that the maximum maintenance-free battery can be charged at a voltage of 16.3-16.4 volts for 20.24 hours.
In our case, we charged the unattended Bosch silver S4 battery with an ordinary charger, with the voltage set at 14.4-14.5 V, it was 90% charged in 24 hours, it should also be noted that at the beginning of charging the current reached 40-50A. To fully charge it was necessary to leave the battery for several hours.