How Long to Charge a Car Battery with a 12-volt Charger?


A vehicle is started using a rechargeable automotive battery. Suppose that its power gets exhausted, it would need to be recharged to power the automobile. If your car battery had gotten out of energy at a point in time and had needed a charge, you would know that there are different chargers available based on their amperage. These chargers have a period that it would take for them to charge a battery; some would take longer than others.

The time it takes to charge a car battery depends on the amp rating of your charger. If you want to charge a car battery for a friend, family, yourself, or colleague using the 12-volt charger, you should read on to know how long it would take for your battery to charge. This post will show you How to Charge a Car Battery?

Battery Charger

A battery charger is used to transfer energy to your rechargeable car battery by passing an electric current into it. Car battery chargers come in various ratings. A charger with a low ampere would charge a battery with a bigger size in a long timeframe, and a charger with a high ampere or rating would charge a battery in a shorter period. You can check out this post to know how to use a car Battery Charger?

Simple Charger

This type of charger works by supplying direct current energy to the battery that is being charged. This kind of charger charges a battery within a longer timeframe because it has a lower charging rating. In most cases, it is not frequently used to recharge a car battery because of this type of charger’s low rating.

Fast Charger

Fast chargers are used to charge a car’s battery rapidly. People who need their car battery in haste use it and need it charged as quickly as possible. Fast charge a battery within a short period because of the high rating they have.

Three Stage Charger

Although it is tricky to explain a three-stage charger, as the charger’s name implies, charges a battery in three stages. In the first stage, the current being transferred is held high and constant until the battery gets to its outgassing voltage; it then moves on to the second stage, where the voltage achieved in the first stage is held at a constant. At this rate, the current being transferred declines until it gets a certain low current, then it switches to the third stage, where the battery voltage is maintained at a full charge.

How long would it take to charge a car battery with a 12-volt charger?

A car battery can take up from 4 to 24 hours to charge depending on the power of the charger you use and the size of your battery.

A 12-volt charger uses three-stage charging profiles; it is a three-stage charger. The three stages in the change process are called bulk, absorption, and float. The bulk stage in a 12-volt charger consists of more than 70% of the recharge, and the current passing through the charger is held constant, and the voltage increases.

The absorption stage of the 12-volt charger would see the charger holding at the absorption voltage and a decrease in the current until the battery is fully charged. The battery will have had a permanent sulphation if the charger’s current passing does not drop after the time it is expected to, and the battery fails to hold a charge.

The last stage, the float stage, is where the charger voltage is said to reduce at about 2 volts and is held constant. The current is reduced to the minimum at about a very low percentage of the battery’s full capacity.

The 12-volt charger’s output can range from 100 milliamps to about 80 amps; 20-50 amps being of the medium output range and 50 amps above being of the larger units.

The battery of a car is said to hold about 48 amps in voltage. If you use a charger with an output of about two amps, considering that it takes about one hour to charge 1 amp on average, it will take a considerable amount of time to get charged. If you do not want a quick charge of your battery and are not in haste to use it, this charger size would be your best bet.

A 12-volt charger with a four amps’ voltage output will take about 12 hours to get a car battery to full life if you are to calculate using the 48 amps’ battery size to predict how long it would take. This charger size is also considered if you need a quick charge of your car battery.

If you want a quick charge of your car battery within a few hours and minutes, you should consider using a 12-volt charger of a higher voltage output to use the medium size from 25 amps to 50 amps, and then the battery would charge up quickly. For instance, if you are to calculate using the 48 amps’ voltage of a car battery, then using a charger of the size 25 amp would take almost 2 hours to get your battery to full charge. If you have a dead car battery and you have no idea how to charge it, be sure to check How to charge a dead battery

Why you should charge your car battery

Your car needs a certain amount of voltage, kick start it, and keep the engine of the car and its appliances running. Apart from the need to have your battery charged to be able to let your car run. The financial costs involved in obtaining a new car battery when the former get dead compared to recharging it is much more expensive.


Now that you know how long it would take a 12-volt charger of different sizes to bring a battery to full charge, you can now plan accordingly and choose what fits your needs and comfort zone.