Can we charge the car battery with an inverter?

By Matthew Joseph Nandirio •  Updated: 09/23/21 •  7 min read

Car battery often needs to be charged if you leave it for a couple of months. So, what if you need to charge it immediately! Look, an emergency can hit anytime. Hence, it’s better to stay prepared. When you encounter your new car battery has no power to start the engine, it’s heartbreaking!

But, I have good news for you. If you have an inverter available in your place, you can use it. You must be aware that potential car batteries are rechargeable. And it is installed to provide electric power to start the engine. Henceforth, the power fosters chemical combustion and propels the vehicle.

The power of the car’s electric system is generated from the battery itself. Therefore, it is natural to charge the battery once in a while. Before we move forward in the discussion, let us understand how we can charge car batteries with an inverter?

The understanding Inverter charging system

An inverter is an electric power device. To be precise, the circuits of the device transform DC (Direct Current) to AC (Alternative Current). Consequently, the frequency of the AC obtained from the device employed with the inverter. The entire system is created with an intricate infrastructure. Moreover, the system involves Frequency and input-output voltage, which is designed on a particular circuitry.

Interestingly, the inverter does not produce power. It is the DC source that generates the power. Therefore, the system is a combination of electric circuitry and intricate mechanical effect. In this mechanical eco-system, voltage plays a crucial role.  

Fortunately, the domestic inverters are rated for 12-volt batteries. The charging circuit generates the power of 13-14 volts that recharge the battery.

Understanding car batteries

Before you start the process, don’t you think understanding the whole mechanism is better? In fact, it sounds interesting!

Car batteries involve a series of circuits. Six galvanic cells are joined together to form the circuits. Furthermore, a single cell provides 2.1 volts. Hence, it means it consists of 12.6 volts altogether. Chemical reaction absorbs the atoms of electrons from the exogenous circuit. Similarly, at the negative terminal chemical reactions release electrons.

While discharge, the reactions drive the electron through an electric conductor. Henceforth, it produces electric currents. At the same time, the acids of the electrolyte provide a reaction with the plates. This, in turn, charges their surfaces to lead sulfate.

On the other hand, the reverse reaction takes place while charging the battery. It means the plates restore their original condition, and the process continues in a cycle.

Types of Car Batteries

The capacity of a car battery cannot be judged based on its size. It completely depends on the mechanism inside it. Let’s take a quick glance at the most common car battery we have in general:

SLI or Starting, Lighting, and Ignition Batteries

Most cars use SLI batteries. As the name suggests, it does the same for a car. Hence, it helps to start the engine, provide power for electrical light and system. Finally, it aids the ignition system inside the car. Therefore, it has a short charge cycle.

Moreover, the SLI battery hardly discharges the power, as it delivers power in short bursts. Furthermore, it is made up of six galvanic cells and creates a series of system format. Each cell delivers 2.1 volts; hence, it consists of a total of 12.6 volts.

Li-Ion batteries

Unfortunately, it is an incompatible version. Advanced and hybrid electrical cars use Lithium-ion batteries. Compared to other types of batteries, it stores a colossal amount of charges. Unlike conventional car batteries, it doesn’t need charging frequently. In general, the lifespan of Li-ion batteries is very short, around 3-4 years.

Lead-acid batteries

This type of battery has hardly any maintenance charge. Unlike SLI and Li-ion batteries, these are sealed and cannot be serviced. Hence, once the battery life expires, it needs to be replaced. Moreover, the application of this battery is a very short burst inside the car.  

How to charge a car battery with an inverter?

Do you know an inverter takes lesser time than the regular charging method? However, it is better not to use inverters frequently. Even though it is simple to use, it might affect both the battery and inverter. If you are in a hurry or have no option available, you can give it a try.

Let’s learn the process thoroughly:

Connection set-up

It is almost like other charging systems. Turn off the power while setting up the connection. After that, hook up the positive and positive cable and terminal together. Follow the same to join the negative points. If you can’t find the positive cables match the color of the ports.

Power supply

Once you finish the primary setup, you can move on to the next. Generally, home inverters utilize direct power from electricity. Again, check the connection twice before you turn on the power. If it’s fine, then proceed to a power supply.

Caution: if you connect the wrong cable, the battery might explode.

Final Check

So, the home inverter generates a high power supply. Hence, it generally takes 2 to 3 hours to charge the battery completely. Try not to exceed the stipulated time. Eventually, it will impact your car batteries.

Points to follow while charging your car batteries:

  • Turn ON the main supply and turn OFF the inverter. This way, you can restore power backup with a car battery.
  • It is better not to use any cable extension. It means, when you hook up the two points, make sure you are not using any third-party connector.
  • Do you have a multi-meter? If yes, use it to monitor the reading of the dead batteries. If the battery is less than 10 volts, it needs to be taken care of. In that case, it is ideal not to use them to charge high voltage batteries.
  • Likewise, you can monitor the reading of both the battery output terminals for safety because SLI batteries need 12-13 volts.

P.S: if the inverter generates a high current rating and equal voltage rating (with battery), it is likely to charge fast.

So, you can see using an inverter for a car battery is convenient. Moreover, it charges the car battery faster. In fact, if the voltage matches; you can charge the battery within an hour, if not two. I hope you find this information helpful. 

The following FAQs add more insight into this topic:

People also asked:

Can we change Car battery at home?

The answer is YES. A HOME INVERTER CAN EASILY CHARGE YOUR CAR BATTERY. Home inverter generally ranges around 12V, which is perfect for a car battery.

Can we charge the car battery overnight?

Actually, you need an entire night to charge the battery fully. LEAD-ACID BATTERY CAN BE CHARGED FOR OVERNIGHT. Therefore, leaving an entire night is no harm.

Can we charge a car battery with electricity at home?

YES, IT IS SUITABLE TO CHARGE CAR BATTERIES WITH ELECTRICITY. Subsequently, you need to follow a few simple steps to charge it:

  • Turn off the charger
  • Put on the positive cables of the charger and the battery terminal together.
  • Hook up the negative cable and battery terminal together.
  • Turn on the slowest charge rate
  • Set a timer and leave.

You don’t need to worry about it whenever you need an immediate remedy to charge your car battery. Use your inverter battery and get the solution. To avoid any unpleasant situation, you can follow the instruction I mentioned.

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Matthew Joseph Nandirio

Matthew Joseph Nandirio is the Founder of walkingsolar. After graduating from the University of Houston in 2002, matt started working as an electrical and electronic engineer for several multi-national solar energy companies. He has a wide range of experiences including solar system requirement analysis, planning, maintaining, debugging and even solar device development through research. He now shares his 20 years of expertise through his articles on the walkingsolar website. Further, he is also the author of two books on Solar Technology, “Solar Power for Villages” and “DIY Solar System for Dummies”.