How Many Car Batteries to Power a House?

How Many Car Batteries to Power a House

Do you live in an area where power outage is a common occurrence, especially during bad weather?

Are you looking to purchase car batteries offering backup to the home energy system to the key energy supply of your home?

Well, then you might be thinking, “how many car batteries to power a house,” right?

In this article, I will elucidate the answer to this question.

So, keep on reading until I finish the article.

Details Elucidating – How Many Car Batteries to Power a House?

I own an average-sized house. A few months back, an electrical outage happened in my locality.

That time, I chose to use car batteries to power my house. And 90 kilowatt hours of energy consumption happened in 3 days. I used a total of 38 pieces of 6 volts batteries rated at 400Ah. Each battery delivers 2.4-kilowatt hours of power.

Let me share the whole perception in detail.

As per the calculation of the US Energy Administration, in a month, the average energy consumption by an American household is – 901 kWh or 30 kWh per day.

So, for 3 days, the consumption will be 90 kWh.

This is a practical idea of the number of backup power systems that are required to disrupt the home’s main power supply.

Moreover, this is also an estimate of 2.4 kWh of power per battery. The batteries are rated ah or amp-hour and available in 3 different voltage options: 6V, 8V, and 12V.

To calculate the battery’s energy consumption, multiply the battery operating voltage and rating and then divide it by 1000.

A 6V battery that comes with a 400 Ah rating has around 2.4 kWh of energy capacity (6 V X 400Ah / 1,000 = 2.4 kWh).

And to learn the number of battery pieces, divide 90 by 2.4 KWh: (90/2.4 = 38).

Benefits of Using a Home Battery Power System

A home battery power system has gained popularity in recent times because of its excellent performance. You will get the electricity supply from a battery bank if the leading power supply service is unavailable.

During severe weather conditions like a hurricane, a home battery power system will deliver many benefits.

Because of climate change, and increasing temperatures, the sea level is rising as well as intense hurricanes are doing a lot of damage in coastal areas.

In 2012, destructive hurricane Sandy did a lot of damage in the district of Columbia. After the hurricane, electricity was unavailable in 7.9 million households and business places.

Moreover, many days after Sandy, 67% of the New York City gas stations were out of gas to sell, leaving home and business generators almost unusable.

Homeowners who own battery backup systems are more fortunate because they will be able to save valuable time. And at the very least, they can use lights on until the grid comes up with the help of a battery backup system.

Why Picking a Battery Backup System instead of A Generator?

Habitants who use an electricity backup system know the importance of the backup system during an extended power outage.

Now the question is, a generator or battery-powered electricity backup system, which one should I pick?

Undoubtedly, a battery-powered backup system is a newer, better, and cleaner backup power option over a generator. However, purposes are the same in both a battery power backup system and a generator.

In this section, I will discuss the comparison between a generator and a battery backup system to make a precise decision while purchasing.


To determine the cost of a battery backup system, you have to know how much power you require for your home.

As I already stated, 90 kWh is the electricity requirement of a medium-sized house for 3 days, and to get the power, 38 pieces of 6 V battery are needed, which are rated at 400 Ah. Such a type of battery will cost you $300 – $500. Given this, your advance cost for a battery power backup system should be $11,400 – $19,000.

In terms of diesel generators, to get the same electricity backup, you will have to cost $4,000 – $8,000. It will run on fossil fuel, diesel. As long as you are using the generator, you will always have an operating cost for fuel.

But for a battery power backup system, a power outlet or solar power will assist you in getting them charged.

In terms of price or cost, a battery backup system is much cheaper than a generator.

Power Source

The power source of a backup power system plays a vital role in operating them.

Generators are powered by fuel or natural oil, or propane. As long as you run a generator, you will have to take assistance from these options continuously. And if these options are unavailable after a hurricane like Sandy, the generator will not come of any use.

The battery backup system runs with the help of electricity. To give the system full charge, you will need to connect it to an electric source. Once the system is fully charged, you will get full support from the system.

You also can use solar energy to power the battery backup system. For this, you have to install a solar panel system. During the day, you can quickly charge the battery backup system with the help of the solar panel.


Generators create much sound and emit fumes while operating. Since they run by taking assistance from oil, they emit harmful gases.

But battery backup systems create less noise and don’t emit any gas. The truth is they are an eco-friendly system.


For those who are planning to install a battery backup system in their house, “how many car batteries to power a house” – is a common question. These systems are cheap and easy to install, operate, and maintain.

Check out the calculation and install a battery backup system as per the requirement.

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