A car battery has several characteristics. On the basis of a car battery’s capacity you can, approximately, say how much energy a battery can store up. The maximal value of inrush current allows you to figure out how fast a car battery can give this energy to the devices that need it. Battery terminals’ voltage allows you to find out the level of a battery’s charging and allows you to determine the operational capability of it. It is exactly voltage that is considered to be the most important. Based on the value of voltage, you can say if a car battery is functioning properly and if it needs to be charged. In case you buy a new car battery, the value of voltage will help you draw a conclusion on the quality of the battery you’ve decided to buy.
How Many Volts Should There Be In a Fully Charged Car Battery Of a Passenger Vehicle?
The majority of cars have car batteries that consist of 6 cell jars. The sum of voltage in these cell jars equals to 12 V. The summing of voltage is possible due to the fact that the cell jars are connected in series. Consequently, there are 2 ways to measure voltage. The first way is to measure the voltage of a car battery as a whole. The second way is to measure the voltage of each cell jar. The second way allows you to detect any problems in each separate cell jar that can decrease the voltage of a car battery as a whole. In order to measure the voltage of a car battery you need a special device, the so-called battery load tester.
The device has 2 contacts that are connected to voltmeter, a resistor and a holder. Before you start measuring voltage, you need to disconnect all the devices of your car from the car battery and leave the car like this for 8 hours. If you start measuring voltage right after you disconnect the devices from your car battery, the values you get may be inaccurate. It is necessary to measure voltage in conditions of room temperature. If the temperature is lowering down for 1 degree Celsius, a car battery is, roughly, discharged for 1 %. In other words, your car battery is charged but, since the temperature is low, you do not manage to use it. It’s forbidden to charge a cold car battery since it will, definitely, result in your car battery being damaged severely. Keep in mind that the lower the temperature is, the worse will a car battery be damaged.
How Many Volt Show Is a Fully Charged Car Battery?
There should be not less than 12,6 V. Actually, there can be up to 12,9 V. Such like car battery is completely charged and ready for use. If you start charging such like car battery with direct current, it will, gradually, be getting warmer. Still, its charge won’t change. After some time, the electrolyte in the battery can start boiling if you leave the battery charging for a long time. If you are buying a new car battery, check if the voltage is not less than 12,4-12,5 V. This means that the car battery is 80-90% charged. If the voltage of a car battery is 10,5 V, such like car battery is considered to be discharged. The thing is that such like battery will be unable to provide car devices with enough electricity.
Regardless of how many volts there should be in a charged car battery, you need to also consider the fact that it’s forbidden to totally discharge a car battery. The threshold value of 10,5 V is standard. It’s a usual value in case of which you start charging your car battery and the charge of your car battery will be replenished with minimal damage possible. If the voltage of a car battery is less than 10,5 V, for example, if it amounts to 8 V, it will be more difficult to charge such like battery. Besides, the service life of the battery will be significantly decreased. If the voltage of a car battery is even lower than 8 V, it may mean that there are irreversible processes taking place inside the cell jars. Very often, it so happens that it’s impossible to charge such like battery. It’s strongly not recommended to bring a battery to such a state.
The second way of measuring voltage is when voltage in each separate cell jar is measured. The minimal allowed value of voltage in each cell jar should amount to not less than 1,7 V. If a car battery is completely charged, each cell jar should have the voltage of 2-2,1 V. At the same time, the electrolyte density in cell jars should differ for not more than 0,02-0,03 g/cm3. How many volts should there be in a completely charged car battery if you are measuring the voltage when the engine of your car is running? When a car battery is being charged with the help of a charging device or it’s being charged from the alternator, the approximate value of the voltage that it gets amounts to 14,2-14,4 V. The increased voltage is necessary for the overcoming of the inner EMF of a battery itself. Otherwise, the current simply won’t get to where it should be.