Car batteries in modern vehicles are equal to 12V DC, which is a well-known fact. But the minimum voltage to start a car can be slightly lower or higher. When we are talking about a chemical power unit, the stability of reactions in it varies. Your battery works under different conditions. So, the result can be different, even within one season.
The measurement of voltage is vital for car battery life. Modern vehicles have strict standards for these conditions. The physical parameters are the basis for daily routine service. Let’s see the main specifications of these elements.
What is the acceptable battery voltage for a car?
The old American cars had 6V power units. That’s why it’s pretty hard to find a decent battery for the oldtimer. The modern standard worldwide is 12V, but this parameter is changeable:
- The normal voltage needed to start the car begins from 12.6 volts.
- At the time of exploitation, this parameter is between 13.7 to 14.7 volts.
You can usually visually check this parameter with the inner electric light system of your machine. If the headlights are bright enough – you are equipped with a battery at decent capacity. However, some old cars, especially German Volkswagens and Opels from the eighties, sometimes have dim headlights right from the factory. Also, there are cases when lights are bright. And the battery is still quickly discharging. In these cases, you ought to test the power unit with a unique gadget – a multimeter.
How to сheck your car battery voltage?
There are two different ways to measure the voltage in the electrical system of your car.
Testing car battery with a multimeter
The testing cycle has the next stages:
- Turn your vehicle off. Check the ignition and headlights. After that, you have to open the hood and see the car battery.
- Set up your multimeter. Modern gadgets are tweaked easily, mind the scale. First of all, car electronics run under DC only. Then, pick the volts. The high mark should be up to 20 volts.
- Inspect the terminals. The orientation varies: sometimes you can find a “plus” on the left side (from your point of view), for some cars, it would be mirrored. In any case, the terminals are marked with the color and the sign. The positive terminal is red, so the red connection cable should go. The negative terminal, respectfully, is black. It is the general case that sometimes colors are different. Anyway, only the proper connection will give you the best result.
- Check the system to know how many volts to start a car do you have. A fresh loaded car battery should provide you 12.4-12.9 volts at the standing vehicle, which is off. Lower parameters mean that the machine drains some power out. Recharge the battery and check the tendency of power consumption.
- Do a load test. It would be an indicator of a battery condition. The minimum point is 9.5 volts. If the voltage dives lower – replace the battery.
Testing car battery without a multimeter
Another practical way we’ve described earlier is a headlight test. When the engine turns over, the headlights shall glare more bright. The working car produces higher voltage. If the headlights are still dim, you must inspect the battery more accurately.
Car battery load tests
So, we now know what a normal battery voltage for a car is. Every power unit has to be tested regularly for a better service and longing lifecycle. The main conditions for a load test are at least 9.6 volts. The lower-numbered battery is completely discharged and needs to be replaced or repaired. The test runs at one-half the CCA rating and a minimum temperature of 70°F.
Veritable loading means using carbon fiber. Under these conditions, portable testing devices will not show you real numbers. The prepared battery has to be in a high charge. Of course, you must follow all safety rules. It would be better to make all these preparations right at the certified workshop.