How To Charge A Car Battery With Home Electricity

Have you ever had the experience of getting ready to go somewhere only to find that your car battery is dead? This is a fairly common experience, and believe me, no matter how careful you are, if you own a vehicle, chances are it will happen to you at least once in your lifetime. If you don’t have a roadside assistance plan to help you get going, then what can you do?

The good news is that there are a few things you can do, including using your home’s electricity to recharge your car battery. To charge your battery, you could either use a 12V battery charger or a household inverter connected to the house power outlet.

Although, at first, using your home’s electrical outlet to charge your car battery may seem like an absurd idea, fortunately, if you’ve access to a comprehensive step-by-step guide and essential tools, you can safely recharge your car battery in less time.

How Long It Takes to Charge A Car Battery?

There are several factors that influence the time needed to charge a standard 12V car battery. These factors can be classified into internal and external factors.

Internal factors:

1. The amperage of the battery.
2. The current retaining ability of the battery.
3. The health of the cells.

External factors:

1. The source you intend to use to charge your car battery.

It is imperative to know that although you are using a battery charger with sufficient power and even if the battery is in good condition, it may take between 5 and 10 hours to charge a car battery fully. However, a completely discharged battery will probably take longer to recharge than one that still has some residual charge.

This is one of many reasons why vehicle owners are advised to perform regular battery checks and why some even take a long time to recharge the battery.

If you plan to charge your car’s battery with household electricity, you will require a battery charger or household inverter. Moreover, be aware that the time required to charge a battery is directly proportional to the charger’s amperage.

In layman’s terms, it means that a high amperage charger, under all circumstances, will charge the car’s battery faster. However, you simply can’t connect a charger to a battery, as this can not only damage the cells in your battery but in many cases, it can cause an explosion and cause damage beyond your comprehension (and I’m not even joking).

Before you buy a battery charger, you should make sure it is compatible by confirming its rated capacity, as charging any vehicle battery that has a lower voltage rating than the battery charger can cause serious cell damage and even an explosion.

However, if you intend to charge your car battery solely to the point where it is capable of starting your vehicle, you may need to make certain compromises, such as using a household inverter as a battery charger.

Read on to explore your options and essential steps.

2 Ways to Charge Your Car Battery from Your Home

1. Battery Charger

The first way to charge your battery using the power supply from your home is with a car battery charger. Of course, you will need to have purchased a car battery charger that is compatible with your car’s battery type.

To start, as always, safety comes first, and you should follow a few basic safety rules, including wearing safety goggles and electricity repellent gloves. Do not stand on a wet surface and make sure that your feet and hands are dry and clean. Before proceeding, read the charger’s user manual thoroughly.

Your first step will be to open the hood, disconnect the black negative battery wire, and then disconnect the red positive wire. Take the battery out of the vehicle and place it on a dry surface. Remove all of the dirt and grime from the battery surface by wiping it down with a wet cloth and baking soda.

Have your battery charger in place beside the battery, but do not connect it at this point to the power outlet in your home. Connect the black negative wire to the black negative port on the charger. Likewise, connect the red positive wire to the battery charger’s red positive port. Do not touch any wire ends with your bare hands. Your last step will be to connect the battery charger to the power outlet carefully.

The majority of modern battery chargers will have an indicator or an alarm that will notify you when the battery is fully charged. A full charge can take anywhere from 3 to 12 hours. The charger will automatically turn off once the battery has a full charge.

2. Home Inverter

With technology becoming more accessible, home inverters have become more affordable, and today, you can buy inverters in all sorts of designs, ratings, and applications. A typical household inverter runs on a 12V lead-acid battery but is compatible with higher voltages, including 24V, 36V and even 48V DC.

Any household inverter, just like a battery charger that has a nominal voltage rating of 12 V, will have a charging circuit capable of recharging batteries at 12 to 14 V. However, it should be noted that household inverters are not designed or built to charge car batteries.
You may be wondering how a home inverter battery differs from a car battery.

Difference between Home Inverter Battery and Car Battery

Well, the main difference is the capacity. While a typical car battery has a capacity of only 50 Ah, a household inverter battery generally has a capacity of 120 Ah – 200Ah. This is a significant difference and also explains why home inverters are able to charge any car battery much faster than any battery charger (because their circuitry is designed to charge batteries with a capacity of ~200Ah).

However, it is not recommended to employ this method frequently but rather only once in a while.

The connection setup for the black negative wire and the red positive wire will be the same as with a car battery charger. Likewise, however, do not connect the inverter to the power supply before all connections have been set up.

A home inverter will use the power from the outlet of your home directly into the battery. Therefore, check all of the negative and positive wire connections before you turn the power supply on. This is very important because the battery could explode if you place the connecting wires in the wrong output ports.

A home inverter has a high-power supply, which means that your battery should be completely charged within 2 to 3 hours. A home inverter is an excellent option for anyone who does not have enough time to wait for the car battery charger method that takes longer.

Sources:
1. Charging a car battery via home inverter – Team-BHP
2. How to choose the right inverter & battery for your home – Mr. Right