The best way to charge a car battery
The car battery is one of its most important components and provides the energy needed for all the electric parts of the car. From starting and moving the car to listening to the radio and music and lighting the car lights, everything needs a battery. Sleeping car battery is a common problem that happens for various reasons. Of course, there is no need to change the battery; In such cases, it is enough to charge it. In this article, we want to talk about the best way to charge the car battery.
How to charge the car battery?
Charging a car battery is not a difficult task. Of course, the best way to charge a car battery is to charge it in a battery shop or with a car battery charger. However, you might like to learn how to charge a car battery yourself when you don’t have access to any help. There are different ways to do this.
Safety tips when charging the car battery
Remember that whenever you deal with a car battery for any reason, first observe the safety tips. The place where you work should be well ventilated, the flame should not be near it, be sure to cover your eyes with protective glasses and your skin with gloves. The clothes you wear should also have long sleeves. There are also some safety tips that we will emphasize when explaining the methods.
Types of car battery charging methods; How to charge a dead car battery?
As we said, there are different ways to charge the car battery. However, only some of them are effective. For example, good ways to charge a car battery are:
- Using a car battery charger;
- solar panel;
- Laptop adapter.
And ineffective or dangerous methods are:
- Normal transformer
- Welding machine
The first method: using a portable battery charger
For this purpose, you can use a home car battery charger that is portable and not very expensive. The procedure is as follows:
1. First, prepare the battery. Check the model of your car battery. Some batteries need to be removed from their case to charge them; But others can be charged without removing it from the car. In most normal cars, there is no need to remove the battery to charge it. Here we assume that you are going to remove the battery.
2. Turn off the electronic devices of the car, including the interior light of the cabin, the air conditioning system, the audio system, etc. If you do not do this, an electric arc may occur to the battery during charging and destroy the battery.
3. First you need to disconnect the negative cable and then the positive cable. The negative cable is usually black and has a – sign on it. The positive cable is usually red and marked with a + sign. Do not reverse the order of disassembly. If the battery has plastic caps on its terminals, remove the caps to access the terminals.
4. Now use the socket wrench to open the negative cable and carefully disconnect it from the battery. Keep cables away from non-identical terminals to prevent load transfer between them. Do the same with the positive cable.
5. Clean the terminals. Before charging first, clean the dirt from the terminals with a special brush. Battery cleaning solutions or a solution of baking soda and water can also be effective.
These cleaners neutralize the battery acid and prevent problems in its operation when charging the battery and reconnecting the terminals.
6. Now you can connect the charger. Make sure the charger is turned off. Connect the positive cable of the charger to the positive terminal on the battery and its negative cable to the negative terminal of the battery. Again, remember not to reverse the order, here you must connect the positive cable first.
7. Now turn on the charger and set it to the lowest value to start. If the charger has a timer, set it for the appropriate time to automatically stop charging. If you don’t know what time it is, refer to the owner’s manual.
8. When charging is complete, you can disconnect the charger cables from the car battery. To do this, turn off the charger, first disconnect the positive cable and then the negative cable. Reconnect the positive cable to the positive terminal and then the negative cable in order. Finally, return the battery to its housing.
benefits
- It charges the battery faster than any other method;
- It is easy to work with;
- It is safe.
Disadvantages
- If the battery is of a type that you have to remove and you don’t have the skills, it is not suitable for you.
The second method: charging the car battery with a solar panel
The second method is to charge the car battery with a solar panel. A standard 100 watt solar panel can provide about 5 amps to charge a battery and it takes about 12 hours to charge a battery below 11.58. Depending on the amount of sunlight the panel receives, it can take up to 2 days.
1. Don’t forget to have a charge controller. You should never use a solar panel higher than 5 watts to directly charge the car battery. Due to the intensity of the sunlight, the voltage of the solar panels is always fluctuating and the voltage is very high, which quickly transfers the current to the battery. In this case, the battery will be overcharged, which is not good for the battery. A charge controller avoids this problem by keeping the current constant.
2. Remove long cables. The cables that connect the panel to the battery should be long enough to install the panel in a place with enough sunlight and to reach the battery inside the car. If you remember, we said that not all cars need to remove the battery for charging. The ends of the cables should have clips or ring terminals so that they can be connected to the battery terminals. The clamps should be labeled positive and negative so as not to be mistaken.
3. Now you need to connect the charge controller to the battery. You must connect the battery to the charge controller first. Never connect the controller to the solar panel before the battery. It should be labeled BATTERY + and – so you know how to connect it correctly.
4. Now connect the panel to the controller. This section should be labeled PV INPUT + and –. Usually the negative cable is black and the positive cable is red.
There are three options for using solar panels to charge the car battery:
- mass charging;
- absorption charge;
- floating charge
Bulk charging is for when the battery is completely discharged. In this case, charging is done quickly; Of course, enough sunlight should be available.
Absorption charging is for the time when the battery slows down the transfer current of the input amp when it reaches a certain voltage. This is the mode where the charging takes place more slowly; But the panel finally completes the charge.
Floating charge is for when the battery is almost full and you want to compensate the discharged amount with just a little charge.
Some solar panels are portable and you don’t even need to raise the hood. Just place the panel on the dashboard and connect it instead of the car charger to charge the battery.
benefits
- It uses renewable energy
- It is easy
Disadvantages
- It takes from 12 hours to 2 days
- You can use it only during the day and when there is sunshine.
The third method: charging the car battery with a laptop
A trick for emergency times when you no longer have a way to charge your car battery is to use a laptop adapter. Of course, this usually takes 15 hours. However, remember that the rated voltage of the laptop adapter is usually around 19 volts, and using it to fully charge the battery is not efficient. However, if you want to use this method in an emergency, read on.
Bring these items:
- Laptop charger
- A 21 watt bulb
- Several cables with different colors
- Insulation tape
- Two clamps
- Digital multimeter
The outer metal surface of the DC jack of the laptop charger is negative, and the inside of the small hole of the jack is positive.
Since the nominal amperage of the charger is 3.42 amps, a lot of current may pass through the charger by connecting the cables. With a resistor, say a 21 watt bulb, you can limit the current.
At a nominal voltage of 19V, this ensures that the current does not exceed 1.1A.
work method
1. Connect the lamp with the cables in series. Fix them with insulating tape. Their order is as follows:
Charger to the cable, for example green – lamp – cable with another color, for example yellow – positive terminal of the battery.
2. For the negative terminal, you need to connect the black cable, for example, to the metal of the charger, which we said is negative, using insulating tape.
Warning: Make sure that these cables do not touch each other.
3. Connect the negative cable to the negative terminal of the battery using a clamp. Now you should have this arrangement:
The negative head of the charger – for example, a black cable – the negative terminal of the battery.
4. Now connect the charger to the power supply.
5. The lamp turns on and after a few minutes the battery voltage reaches 12.5 volts.
6. Measure the battery voltage every half hour. You should probably have 13.1 volts after 6 hours.
7. If the lamp light dims, it indicates that the battery is charging. When it reaches 15 volts, it is enough. It probably takes 15 hours to fully charge.
30 minutes after stopping charging and disconnecting the cables from the battery, the voltage should reach 12 volts.
In practice, although laptop adapters are 5 amps, they don’t pass more current around 0.5 amps and the voltage drops.
benefits
- Useful for emergencies
Disadvantages
- It takes a lot of time and is not very efficient
- It requires technical knowledge
- It may damage your laptop adapter
- Your car battery must be healthy.
The fourth method: charging the car battery using a normal adapter
This method is just like the laptop method. Of course, most laptop adapters are 19V, but you can use a normal 12V adapter with 5 amps. Of course, you must have a voltage booster to create a higher voltage. Create the same circuit as described above and use a light bulb, voltmeter and ammeter. This method is more efficient than the laptop method, but it is still not recommended.
benefits
- It is better than laptop adapter
Disadvantages
- The battery must be healthy
- It takes a lot of time.
The fifth method: charging the car battery with a transformer
The voltage required to charge the car battery is more than 14.8 volts and its floating value should be 13.8 volts. Only then you will have 10 amps of current and you can charge the battery in a few hours. If you also use a step-up converter, the current capacity will decrease. This is because transformers typically provide 11.2 to 12 VAC of voltage and 5 amps of current. The power of these transformers is obtained by multiplying 11.2 by 5, which is 56 watts.
A converter with an efficiency of 85% reduces the power of the device to 47 watts, which even with an output of 14.2 watts, the current will be about 3.3 amps. This amount requires more than 30 hours of time, which will not be effective at all. Therefore, with the transformer, you can only charge the dormant battery to the extent that the car starts, and it is not suitable for charging the battery.
The sixth method: charging the car battery with a welding machine
Some people have also used this device to charge the car battery; But firstly, it requires a lot of skill, secondly, because it is an industrial device, it may be dangerous.
summary
The car battery is responsible for powering all the car’s electrical components. Sometimes the car battery does not need to be replaced and by recharging it can be used for a longer time. There are various methods for this, the safest and most efficient of which is to go to a battery manufacturer or buy a car battery charger.
There are also methods such as using a laptop adapter, normal adapter, transformer and solar panel, which are usually not very efficient and you need a little technical knowledge. On the other hand, there are methods such as using industrial devices such as welding machines, which may be dangerous, and please do not think about these methods if you do not have knowledge and skills in this field.
Have you ever tried any of these methods? If it was successful, please let us know in the comments how you did it and what tools you used.
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