Since batteries start the power unit, every vehicle owner should be aware of how many volts a car battery has, and how to constantly maintain it in normal condition. It will also help you determine if the battery is in good condition or not. In this article, you will learn more about car batteries and how to increase their life expectancy.
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It is important to test your battery and electrical system periodically, not just when it is beginning to show signs of weakness. Whether it is you or your mechanic who does the testing proactively, as long as you test it at least twice a year will help you minimize the chances of failure.
How many volts does a car battery need to start?
More often than not, while both the generator and the engine are in the working state, the voltage of your battery should be within 13.7 -14.2 volts. If higher, it can be harmful to the battery, while if lower, then it is not fully charged.
Have you ever asked yourself, “what is the minimum voltage to start a vehicle?” According to experts, there is no exact answer to this question. In the standard state, a fully charged battery should display 12.6 – 12.7 volts on a voltmeter reading. Depending on certain conditions, this indicator may change a bit, and there is nothing wrong with that. For example, some automakers assure that their products have a voltage of about 13 – 13.2 volts, however, you should not measure it right away after charging the battery. As per experts, you have to wait at least an hour, then it should drop from 13 to 12.7 volts.
As the atmospheric temperature drops, the battery current drops too. In such a case, the voltage is difficult to estimate. However, it also falls down a bit and if it is lower than 11.5 volts, then it means that the battery is discharged by 50%. In this case, the device will require an urgent charging as its usage in such a state will result in plate sulfation, which in turn will reduce the working capacity of the battery and the duration of its service.
Nevertheless, even with a low voltage range, it is pretty possible to start a car or vehicle. If the battery is in good condition, or it does not need repair, and the generator supplies battery charging during the engine work, it can be safely started.
In spite of all that, if the voltage level falls below 11.6 volts, and the battery is almost completely discharged, its further usage without performance check and charging is impossible. However, in reality, the usual voltage for most of the passenger vehicles can be in the range of 12.2 – 12.49 volts, which signifies an incomplete charge. A decrease in quality and the performance of the device starts in the case of reduction to 11.9 volts or less.
How do you test if a battery is good?
The easiest way to check your battery’s voltage involves using a voltmeter, which measures the electrical potential difference between two points in an electrical circuit. Experts recommend using a digital voltmeter because they are much easier to use.
Perform this test 12 hours after shutting off your vehicle to give any surface charge a chance to dissipate, to get the most accurate reading.
Step 1
Make sure the vehicle is shut off.
Step 2
Detach the battery’s positive terminal cover. Inspect the terminal for any corrosion and clean it off if needed. Then, you will have to connect the voltmeter’s positive lead to the battery’s positive lead. Next is connect the voltmeter’s negative lead to the battery’s negative terminal following the same steps you did for the positive end. Then, you are all set to check the voltmeter readings.
Step 3
Look into the reading. A fully charged battery will usually show a voltmeter reading of approximately 12.6 to 12.8 volts. If the voltmeter is displaying a voltage reading anywhere between 12.4 and 12.8, that indicates that the battery is in good condition.
Step 4
Any voltage reading higher than 12.9 volts is a good sign that the battery has excessive voltage. In cases like this, turn on the high beams to drain too much voltage surface charge. In addition, an excessive charge could indicate that the alternator is to blame for an overcharged battery.
Step 5
Charge the battery if the voltmeter shows a voltage lower than 12.4 volts. However, if the voltmeter is reading anything lower than 12.2 volts, you should think about trickle charging the batter. This basically means that you would be charging the battery at a much slower rate, which enables you to prevent any risk of applying excess charge amperage that could add a lot of excess heat and off-gassing—and in extreme cases—explosions.
What causes a car battery to lose voltage?
Batteries can experience voltage drop for various reasons. Familiarizing the most common causes can help you address the problem more quickly and effectively. While there are a lot of reasons why a battery may be experiencing voltage drop, some reasons are much more common than others. Check out the tips that we have prepared on what to test and do if the voltage seems to be dropping on your battery without any obvious cause.
Starter and Battery Connections
In general, the very first thing you should check is the battery and the started connection. These are the most often encountered problems with any voltage drop in a battery. After checking the battery and the starter connection and are certain that neither of them is the culprit, then you will want to move on to other tests to find out what really is causing the problem.
Checking Connections
The connections must be checked once you begin to notice that your battery is losing voltage. Be sure not to use an ohmmeter because you will not get an accurate reading for your battery as this meter is only capable of measuring the continuity of the connections. It does not measure its ability to hold a high amperage current load. There are other ways to be able to get an accurate read on your battery.
The most accurate way to test the connection on your battery is by a voltage drop test. It can be done quickly since you do not have to disassemble anything. You can test the voltage drop with your digital voltmeter once you have successfully created a load in the circuit that you intend to test. If the connection or the circuit has too much resistance, some voltage is going to flow right through the digital voltmeter. This will provide you a voltage reading.
Resistance
Too much resistance of your high amp circuit is an overlooked problem that can cause the voltage to drop in your batteries. Be sure to check if the cables are corroded, loose, or damaged.
Resistance is usually caused by cables and battery terminals that have not been properly and regularly cleaned. Corroded terminals or cable could cause a big problem. In some cases, corrosion can be difficult to identify or locate. Regularly cleaning the terminals and cables can help prevent the occurence of this resistance problem. The best way to clean off corrosion is by using a wire brush, which can be purchased at a very low price at any hardware or auto parts store.
Battery cables with ends that are bent out of shape or replaced can also be a source of a good deal of resistance. It does not necessarily need to have an increase in the battery’s resistance before trouble occurs. It is crucial to keep an eye out for these things, which can be done by checking your terminals and cables religiously. This will prevent the occurence of battery resistance problems in the future.
What kills a car battery?
A dead car battery can be troublesome, but it can be avoided. To effectively prevent a dead battery problem, first you have to know what causes one. So, check out this small list of items that could explain why your car battery keeps dying.
- Increased Parasitic Draw
Your car battery supplies power to things like the clock, alarm system, and the radio, even while the vehicle is off. These things should not have a major impact on your battery. However, there are things that may drain a car battery when it is off, such as door lights, interior lights, or even bad fuses.
The alternator charges the battery while your engine is running, which is why you normally do not have to worry about the battery draining while you are blasting the radio while on a road trip. But keep in mind that the alternator cannot recharge the battery when the engine is off, allowing small electrical accidents to drain the battery entirely. The battery strain caused by these electrical mishaps is known as a parasitic draw.
You can avoid these parasitic draws by shutting off every light and making sure the glove box, trunk, and doors are completely closed and latched before leaving the vehicle.
- It is extremely Hot or Cold outside
Hot summer days and freezing winter weather may cause problems for the vehicle’s battery. Newer batteries are designed to have more resistance to extreme seasonal temperatures. Yet if your battery is older, intense temperature could weaken its performance—in extreme cases, it could even cause the battery to die completely. If you notice your battery having difficulty braving the elements, go to your trusted technician or service facility so they can help you diagnose and fix the issue.
- High frequency of Short Trips
Cranking the engine consumes an enormous amount of power from the battery, but as mentioned earlier, the alternator recharges the battery while the engine runs. However, if you are taking a lot of short drives, the alternator might not have enough time to effectively recharge your battery between pit stops—especially if you are using an older battery. Over time, frequent short trips can shorten your battery’s life expectancy.
- If you are using an Old Battery
Nothing lasts forever, including your vehicle’s battery. It is possible for your vehicle’s battery to last up to five years, but that depends on how you drive and where you live. Frequent short trips, extreme temperatures, and typical everyday use could shorten the life of your battery to two or three years. Even after a jumpstart, if your vehicle battery dies quickly, it might be time for a new battery.
- Forgetting to turn off your Headlights
The first things to check are your lights, if your battery keeps draining. A lot of newer vehicles have headlights that are designed to automatically turn off after a certain amount of time. But if your vehicle does not have this feature, your headlights may stay on until you turn them off or until your battery has been completely drained.
- Battery connections are Corroded or Loose
The positive and negative terminals attached to your battery can sometimes get displaced over time. These terminals may also be affected by corrosion. If your battery’s terminals become corroded or loose, you might have difficulty starting the vehicle since your battery cannot properly transmit its power. Your engine could even stop working or stall out while driving or damage the electronic components of the vehicle. You can prevent corrosion-related problems by periodically cleaning your vehicle’s battery terminals. If you want to know more about why vehicles continue to stall, click here.
- The battery is Not Charging while you drive
Your vehicle relies on your battery when you fire up the engine. However, your battery relies on the alternator to help it stay charged when your vehicle is running. If your alternator is faulty or not working properly, it cannot power your battery effectively, which can make it difficult to start your vehicle even if you were just driving. If your vehicle will not start after driving, there is a possibility that alternator is the culprit.
Conclusion
There is no specific minimum requirement as to how many volts your battery should have to start the vehicle, but it is important to know that there are various factors that can negatively affect your battery.