How Many Volts Is A Car Battery?

Car battery voltage range is different for every situation of your car status

The car battery is the juice box of the vehicle and thus has to be in good condition always to power the car.

One sign of a car battery in condition is its voltage thus the voltage reading of the car battery should be at its best always.

Such type of a car battery is always up to the task of supplying adequate electrical power for the vehicle to power up for the electronics like the stereo and AC to power up.

So, you may be wondering how many volts is a car battery? A car battery in good condition should give a voltage reading that is not significantly different from 12.6V.

This shows that the battery is in good condition and able to meet the power demands of the vehicle’s engine and also the electronics like the stereo, headlights and AC system.

The voltage reading of a good car battery might not always be at this exact point as it tends to vary with certain conditions.

For instance, temperatures affect the voltage of the car battery and it might be seen to slightly lower than this figure on a cold day.

When the car battery is running, you might also notice a significantly greater figure than this because of the in-built alternator whose main function is to charge the car battery while it is running.

What Is The Average Car Battery Voltage Range?

For a good car battery, the voltage should range from 12.4V to 12.7V. This should be the case when the car battery is just resting and there is no source of drain from it.

Some car battery brands might show a voltage reading that is slightly different from this but a car battery in good condition should not deviate from this significantly.

A car battery in bad shape is not able to hold charge and as a result will deviate from this range even after being immediately charged.

This is due to old age or even just components that are damaged within it.

When fully charged the average car battery should have a voltage reading of 12.6V, and not a significant deviation from this reading.

When the car is starting the voltage reading should not be significantly less than 10V for your average type of car battery.

However, the average car battery will have a voltage reading higher than these figures due to the action of the alternator, it should show a reading between 13.5V and 14.7V.

A reading that deviates from this range significantly either on the upper side or lower side shows that their might be an issue with either the car battery or its alternator.

There is no exact value for the voltage reading of a car battery at any state as there are different car battery brands and qualities.

The voltage is also usually dependent on a number of factors such as temperature and other conditions.

The figures given below are not the exact figures but are rather an approximation.

1. Car Battery Voltage Range In The Morning

The voltage of the car battery in the morning depends on the state of the battery as well as the temperature.

Cool temperatures tend to affect the car battery such that they will show a lower reading.

In normal mornings, the car battery might show a reading of slightly above 12.2V.

The cold temperature in the morning cause the car engine to be quite cold and hence requires the car battery to put in more effort to even start it.

As such when you take the reading in the morning it will be quite low due to a significant drain from trying to start the engine.

2. Fully Charged Voltage Range

When you connect your car battery to a car battery charger for enough time, it should have recharged well enough and thus its voltage reading should be at its maximum.

After the battery has been fully recharged the voltage should indicate 12.6V, some car batteries can give a higher reading than this.

This is in the case of a car battery in good condition. If the car battery gives a voltage reading significantly lower than this, then it is probably damaged.

To get the accurate reading, you should take it after the car engine has been off for quite some time.

Like in the morning if the car has been parked idle for the whole night. The reading here is usually regarded to as the “resting voltage.”

You are probably going to get a wrong and inaccurate reading when you take it after the car has been on for a while. In many cases this figure is usually quite higher.

After a full charge, the car battery should give a voltage reading close enough to 12.6V.

A significant deviation, on the lower side of course, indicates a car battery which is nearing its demise or even just damaged.

You should be aware that a car battery that has been halfway used normally gives a reading of approximately 12.2V.

3. Voltage Range When Your Car Is Starting

On igniting your car engine, the juice box powers the starter motor in order to propel the engine.

At this point the voltage reading will decrease slightly and then rise to the normal starting voltage.

A good car battery should give a reading that is not less than 10V when the car is starting.

In areas with cool temperatures the car battery will be forced to work twice as hard to turn the engine which is quite cold then.

Therefore, the voltage reading from the car battery should be expected to be lower than in normal conditions because of the higher discharge rate.

In the case of a car that has been left idle for long, the engine might be cold and thus require the car battery to put in more effort to power it up.

This is the same scenario as in the case of under cool temperature conditions.

The battery is left significantly drained as it will take relatively more power to start the engine unlike a normal one.

4. Voltage Range When Your Car Is Running

When the car is being driven, there are a lot that happens in the trunk that we most car owners are unaware of.

When you take the reading of the car battery when it is running, you will get a surprised figure of between the level of 13.5V and 14.7V.

As the car runs, there is a device called the voltmeter that works to charge the car battery.

This is through a series of chemical and electrical reactions that make the car battery charge.

As a result, the car battery gives a higher reading than when it was both resting and even after just being recharged.

When you take the reading and realize that there is a huge deviation from either 13.5V and 14.7V, then there is need for alarm.

This would indicate that your alternator is damaged or even that your car battery is faulty.

Why Is My Car Battery Voltage Too High?

You might have taken the voltage reading for your car battery and realized a reading that is significantly on the upper side.

Most car owners would think this is a good sign, but not always.

A voltage reading that is too high than the rates given above might indicate, for one, that the car battery has been overcharged.

A car battery can be overcharged because of leaving it connected to a charger for longer hours than expected.

This might also arise because of an alternator that is not regulated and thus provides too much charge to the car battery.

The overcharging causes production of too much hydrogen gas that is at risk of exploding when exposed to the slightest of sparks.

Overcharging might also occur because of setting the car battery charger to recharge the car battery using too much current.

This will cause the battery to obtain too much power especially if you leave the connection intact for a long time.

Special chargers are designed to be automated and sense when the car battery is fully charged and then ending the charging.

As seen above, when the battery gets overcharged, you will be shortening its lifetime and also putting yourself at risk.

You can avoid overcharging the battery by setting the car battery charger at a lower current or even just using a trickle charger if you are not going to be around as the charging takes place.

Why Is My Car Battery Voltage Too Low?

When you are testing for the voltage of your car battery, you might have realized that the reading shows a voltage that is too low.

There are many reasons that might cause this, the most common one being that the car battery is just too old. A normal car battery has a lifetime of four to five years.

When it gets past its fourth year, it would lose its ability to hold charge and thus show a reading that is too low even after being recharged.

When you leave your car lights or stereo on for a long time, then the car battery voltage is bound to be too low.

Such electronics drain the car battery too much that you might just need a jump starter for your car battery to start the car.

Some reasons that cause the car battery to show a low reading might be because of damage of the components of the battery.

This might be because of bulges on the sides of the car battery or even leaks on the car battery.

Corrosion build up that normally occurs on the terminals of the car battery may also cause connections issues and thus the voltage of the car battery eking quite low.

A short in the car battery might also cause the car battery to give a significantly low voltage reading.

This occurs due to faulty separators between the cells of the car battery that make it unable to work well.

When you abandon your car battery for long and do not use it, then the voltage reading will probably be low.

This is because the car battery will lose charge internally due to sulphating that will have occurred in the car battery.

Thus the reason why the voltmeter will show a voltage reading that is too low.

Why Does My Car Battery Voltage Drop Overnight?

You might have noticed a drop in the voltage reading of your car battery when you go to check it in the morning.

There are many reasons that cause this to happen even as you try to keep your battery charged regularly.

One of such reasons is that you might be looking at a case of a parasitic drain.

These work to drain significant voltage to your battery and occurs overnight when you might not even detect it and while the alternator is not recharging the car battery.

Parasitic drains usually arise from electrical shorts or having worn out devices that are faulty such that they do not get fully switched off even when you try to do so.

Such type of devices continues to drain power from the car battery even after you have turned off the ignition switch.

Another reason is because you might have just forgotten to switch of the headlights and other lights on the car like the door lights.

Such electronics drain the car battery significantly so much that when you try to switch on the car battery it might not start the car.

How Many Volts Does A Car Battery Need To Start?

You might be worried whether your car battery would be able to start your car after a long time driving.

This is especially the case when you do not have an alternator in good condition and thus the battery does not get charged effectively as the car is running.

This always leaves doubts on the reliability of the car battery to power or even just start the car the next time you turn the ignition key.

There might not be an exact figure on the volts required to start a car as there are different types of cars fitted with different engine sizes.

However, a voltage above the 12V level should be enough to start your car easily.

The voltage level will rise if you have a good alternator in place that will work to charge the car battery as the vehicle runs.

Is 12.2volts Enough To Start A Car?

There is no exact answer to what voltage is needed to start a car.

However, if your car battery voltage is not lower than 12.2V then you are safe. This is the voltage reading that most cars would start on with ease.

You might have experienced a situation where your car battery is unable to start your car even with a voltage of 12V.

This occurs after leaving the car idle overnight and can be a disappointment especially when you are trying to be punctual for work.

At What Voltage Is A Car Battery Dead?

The worst thing you have to deal with in your car is a dead battery; especially when you had not been expecting that.

You can get to know whether your car battery is dead by measuring the voltage reading, a technician would come in handy.

You can perform this either through electrolyte gravity voltage test or through open circuit voltage test.

For the former test, a reading of 1.124 volts shows a dead battery, while for the former a reading ranging between 11.75 volts to 11.89 volts indicates a dead battery.

How Do I Check The Voltage Of My Car Battery?

Checking the voltage of car batteries should not be a difficult task and anyone can accomplish this if the follow the procedure.

You will not even need a technician to get this done, unless you are just lazy.

The car battery’s voltage can be checked using several methods, provided you know how to use the devices in these methods.

You may go for a multimeter, a voltmeter, perform a load test to get to know the voltage of the car battery.

You can click here to get the procedure for testing or rather checking the car battery voltage.


Regular checking of the car battery voltage is important to keeping up with its condition.

This is to help you as the car owner to plan so that you know what may be causing the car battery to get into poor condition.

This can be regarded as a type of maintenance practice as will enable you understand what is affecting the performance of the car battery.

Driving a vehicle with a car battery in poor condition puts you at risk of being stranded or even getting late for meetings due to battery problems.

The bad battery may even extend damage to the components of the car like the alternator and other electronic equipment within the car.

Regular checking of the car battery voltage is recommended so that you can track the performance of your car battery, this will help avoid practices that shorten the lifetime of car batteries.


Written by Kane Dan

Checking your car battery with having a good knowledge can lead you to succeed in knowing the right voltage

How To Test A Car Battery

Cleaning battery connections on my car with the easy methods

How To Clean Battery Terminals