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how many solar batteries are needed to power a house

How Many Solar Batteries Are Needed To Power A House?

Do you need to determine how many solar batteries are needed to power a house?

This guide will help you figure out how many batteries you will need.

This guide goes over how to calculate your home’s energy requirements, how much energy you will need to store for your requirements, the different types of solar battery systems, and how to calculate the number and type of batteries you’ll need to meet your needs.

Finally, we answer the most commonly-asked questions about solar batteries for powering a house.

Hopefully, this guide will answer all of your questions.

But in case it doesn't, please leave us a comment below.

How Much Energy Do You Need?

how many solar batteries are needed to power a house

Determining energy consumption will help you deduce how many solar batteries are needed to power a house.

Let us look at a few factors below that can help you calculate a near-accurate energy consumption figure.


The best way to figure out your home's electricity consumption is by looking at your electric bill.

Most electricity bills state the total power usage for a month at the bottom. You will see a figure in kilowatt-hours or kWh.

Use this figure to calculate the yearly electricity consumption to get a reasonable estimate. This estimate will help you determine precisely how many solar batteries are needed to power a house.

Please note that power consumption for every month will not be the same. Air conditioning causes more electricity consumption in the summers, for example.

To prevent miscalculations, it is recommended to gather all monthly bills from the past year is recommended. Use these to get a total yearly figure which you can divide by 12 to get an estimate.

If you do not have all bills for the past year, a single bill should also give you a rough estimate.

Number of Days of Backup Power

A solar battery system that can power a house for several days is extremely expensive, on the order of $10,000-$20,000 or more.

If you really need that much power, then we recommend speaking with a local solar installer about your options.

That said, you can affordably power a lot of critical appliances with much less expense using off-the-shelf, off-grid solar generators like those made by Ecoflow, Jackery, and Bluetti. 

They won’t run your oven and heater, but most other appliances can be run for days on them.

In any case, it’s important to decide how many days or hours of backup you need before proceeding to pick a solution.

Energy Storage Requirement

how many solar batteries are needed to power a house

Next, you need to determine how many Watt-hours of backup energy storage you’ll need to keep your appliances and electronics working.  

The best way to do this is to select the appliances you’ll need to keep running and look up their Wattage rating (see our appliance power chart for a guide). 

Then, multiply your total Wattage needs times the number of hours each day you’ll need to keep them running.  This will give you the daily Watt-Hours of storage you’ll need to keep things on.

Finally, multiply your daily requirement by the number of days or hours you need to keep the lights on.  This is your Watt-Hour energy requirement.

Battery Specifications

Most solar generators work off of 12V, 24V or 48V Lithium Ion Phosphate batteries

The power from these batteries is converted into 115V AC power using an inverter which can be purchased separately or comes included with your generator.

Multiply the amp-hour (Ah) rating and voltage of a battery to figure out how many Watt-hours of energy it can store. For example, a 12V 200Ah battery can store 2400 Watt-hours of energy.

Number of Batteries

Battery storage that can work for three days should aim to provide 90 kWh of electrical energy. If a battery provides 2.4 kWh of energy, you will need 38 batteries to power your house correctly.

However, this is just a rough calculation. You need to determine and follow all the steps above to help deduce your power consumption. You can then determine exactly how many batteries you will need.

Also, take charge loss, power loss to the converter, and other factors into account. Ideally, you will need a few more batteries than the figure you obtain to avoid problems.

Different Types of Solar Battery Systems

how many solar batteries are needed to power a house

You can design various solar battery systems based on needs, preferences, and other factors.

Now that you have an answer to how many solar batteries are needed to power a house, its time to look at types.

Solar Battery System For Saving Money

If you wish to install a solar battery system to save on electric billing costs, you must know your power consumption rate.

A flat rate requires a system with good storage so that you only use the grid when necessary.

Switching to a solar system will help you save only if your solar panels are powerful enough to hold more charge.

With a variable-rate plan, you need backup power to switch to solar during peak-rate hours.

Solar Battery System For Resiliency

Most people invest in a solar battery system to obtain backup power when they cannot rely on the grid.

Power shortages or outages often make people invest in solar panels for resiliency.

Such a system can help power the entire house and appliances whenever the power goes out. So, how many solar batteries are needed to power a house for resiliency? Well, it depends on your choice.

The number of appliances you want to power and other factors will help you deduce whether you need less or more power.

Invest in more batteries to keep most of your appliances up and running. You will need 4 or more batteries for increased capacity if power outages in your area last for days.

Solar Battery System For Off-Grid (Self-Sustaining)

how many solar batteries are needed to power a house

Complete independence from the grid requires a massive storage capacity and power bank.

You will need more than the usual amount of solar batteries to keep your entire house powered throughout the day and every day!

f you have a 9 to 5 job and are not home most of the day, you will consume only 30% of the electrical energy required in a day by most people.

This and many other factors will help you correctly deduce the number of batteries you need to power your house daily.

It is also a good idea to account for sunlight hours and purchase extra batteries just in case.

It would help if you also decided whether you need similar amounts of electricity at night and what times you can easily do with no electricity backup.


how many solar batteries are needed to power a house

Here are some if you plan on powering your house with solar batteries.

  • Make sure you invest in enough solar panels to boost storage capacity for peak-rate hours. This will help save money.
  • To reduce the dependency on the grid, you need to calculate power consumption, days, and battery specifications.
  • A single lithium-ion battery is sufficient to power basic lights and electric systems during a power outage.
  • Self-sufficient battery storage demands 8 to 10 batteries. This will cover lengthy power outages and sunlight shortage.
  • Most solar batteries have a capacity of 10 kilowatt-hours. Based on this, 2 or 3 batteries are ideal for short power outages.
  • You will need more batteries for a battery system designed for resiliency and even more for self-sustenance.

Frequently Asked Questions

How long can a solar battery power a house?

Average households require 2 kilowatts and 1000 watts of power during a power strike or outage.

This is if the shortage lasts for only a few hours. Extended power outages demand more energy.

The overall battery capacity, number of batteries, stored charge, and number of appliances also determine how long a house can be powered using solar batteries. 

How many batteries does it take to run a house on solar panels?

A 6-volt battery with 400 amp-hours provides 2.4 kWh. A typical American house will require nearly 38 batteries to provide 90 kWh. This should be sufficient for a 3-day power depletion.

How many solar panels and batteries does it take to run a house off-grid?

The average consumption of 7 kilowatts will require thirty-five 200-watt panels. This should be enough for complete independence from the grid.

If you opt for solar panels with a higher wattage, for example, 350 watts, you will need only 20 panels.

How much does a whole house battery cost?

A whole-house battery usually costs $4000, given the battery can provide 4kWh—larger batteries such as those that provide 13kWh cost more. A single unit may cost about $15,000 or higher. 

Battery type, panel placement or location, backup power needs, and the inverter type are several factors that may vary power storage.

You will need a battery with a higher capacity if you have less sunlight, more electrical needs, or solar panel placement issues.

How many 12V batteries are needed to power a house?

A 5-watt panel can quickly charge one 12-volt battery. If your energy consumption is 90 kWh, you will need about 19 to 20 batteries.

How many solar panels do I need to power a 3000-square-foot house?

The estimated yearly electrical consumption for a 3000-square-foot house is 14,130 kWh.

You will need about 42 to 45 solar panels to support a similar-sized property.

Final Verdict: How Many Solar Batteries Are Needed To Power A House

As mentioned in this guide, there is no single answer to how many solar batteries are needed to power a house.

It depends on the type of solar system, electricity consumption, battery specifications, number of outage days, sunlight availability, and even solar panel placement. 

You can look at your power bill to roughly estimate how much electrical energy you use every day to deduce how many batteries you will need. It is always a good idea to purchase extra batteries to avoid problems. 

So make sure you keep all factors in mind, make calculations, and even consult other users to make the right choice. 

Good luck!

About the Author David Roberts

I'm a Mechanical Engineer who's obsessed with solar energy and sustainable living.

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