What should be the voltage on the car battery?

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:42

Car owners would do well to know what the battery voltage should be. Normal indicators allow us to talk about sufficient battery charging and its high operational capabilities. With reduced power supply parameters, problems may occur with starting the engine and the operation of auxiliary devices necessary for comfortable operation.

Main Measuring Instruments

Before talking about what the battery voltage should be, you need to familiarize yourself with the basic devices designed to take indicators. With their help, you can make the most accurate measurements in the normal state and under load.

1. Multimeter - a universal device for working with various electrical circuits. Instruments can be analog or digital. However, as a rule, the latter ones are used. The readings in this case are displayed on a special display, which has a small size.
2. Load fork. In a simple version, it contains a voltmeter withthe ability to measure resistance. The body is usually made of metal. It is located on a special handle. More complex devices may contain additional elements.

Using the load plug too often is not recommended, as regular measurements may degrade the battery condition. In the case of a multimeter, there are no restrictions.

Indicators in the normal state

First you need to understand what should be the voltage on the car battery without the load created by additional devices and the engine at startup. Ideally, the power supply should output 12.6-12.8 volts. At lower values, it is advisable not to use the battery, since lead sulfate will form on the plates, which can lead to a decrease in capacity.

Load performance

You also need to know what the battery voltage should be when the engine is not running, but under load. In this case, you can determine the performance of the power supply. When using a load plug, the voltage must in any case be higher than 9 volts.

If the drawdown is too high, then first of all it is necessary to charge the battery and retest. Indicators will not increase when the battery is depleted.

Table for determining the level of charge

Immediately after no-load measurements, the condition of the battery can be determined. Knowing abouthow much voltage the battery should produce when fully charged, it is quite easy to establish its capabilities in a particular situation. To do this, you can use the presented table.

Voltage in volts	Percentage charge level
11, 94	10
11, 98	20
12, 04	30
12, 12	40
12, 20	50
12, 28	60
12, 36	70
12, 46	80
12, 58	90
12, 70	100

Measuring with the engine running

When the car engine is running, the indicators increase slightly. Typically, the battery voltage fluctuates between 13.5-14.0 volts. If the charge level is too low, the readings will increase as the generator will operate in boost mode.

Although the battery voltage should be higher when the engine is running, it may be slightly higher for 10-15 minutes after starting. If during this time it does not recover, then there is a problem withgenerator or electrical equipment.

After measurements, it may turn out that the voltage has not increased, but has fallen somewhat. In this case, the battery simply does not have time to charge normally. To check, it is recommended to gradually start electrical consumers, making measurements between turning on the devices. Indicators will drop significantly (by 0.2-0.5 volts or more) if the generator is faulty.

Battery Operating Rules

Even if you know exactly what the voltage on the battery should be, if you use it incorrectly, it will not be possible to maintain it for a long time. Therefore, special battery operation rules should be followed.

1. Before starting the engine, it is necessary to turn off the power consumption devices. In one attempt, it is not recommended to give a load lasting more than 5-10 seconds.
2. When driving around the city in winter, it is advisable to carry out additional charging of the battery using special devices, since the engine in this case runs at low speeds.
3. Checking the integrity of conductive elements should be done regularly. Possible current leakage can lead to untimely discharge of the battery. Thus, the operating voltage will be reduced.

About recharging

The power supply must be recharged at the right time, then the voltage will be optimal during operation. However, during such an eventmeet certain requirements.

1. Charging must be carried out at a positive air temperature.
2. Fill plugs should be unscrewed and left directly in the holes before connecting to the mains.
3. The appliance used must be 16 volts.
4. For 20 minutes after turning off the charger, do not tighten the plugs. The accumulated gases must completely leave the interior.
5. The device is charging in a room with supply and exhaust ventilation.

As a conclusion

Information about what the battery voltage should be will help you to identify problems with starting the engine and the operation of various devices without unnecessary difficulties. If the indicators are normal, then the reasons should not be sought in the power system.

It is desirable to make measurements using the above-mentioned instruments. It is impossible to use an on-board PC for these purposes, since the error will be too high. This is primarily due to the peculiarities of connecting the device directly to the network.

Check the battery regularly. If the car has not been driven for several days, and the measuring device shows a significant decrease in voltage, then the power supply is almost exhausted.