How to Choose a Home Battery Backup System?

A home battery backup system is essential to cover any dips in energy production for a home solar system.

If you still rely on the grid for power, you’ve likely had to deal with your fair share of outages. A home battery backup system can help keep the lights on and everything working to minimize disruption to your life.

However, not any backup battery will do. The type you might have stored in your vehicle to jump the car isn’t sufficient to supply an entire home with energy. Read on to learn how to choose a home battery backup system, including factors to consider, costs, and the different types available.

What is a Home Battery Backup System?

A home battery backup system stores reserve energy. It can operate on a standalone basis or as part of a home solar system.

The backup battery gets its charge via multiple means, usually solar charging or the home’s connection to the grid.

Stack multiple batteries, and you have plenty of stored power for the days when your solar system isn’t producing as much energy.

How Does a Backup Battery Work?

How a backup battery operates depends on how you have it connected to your home electrical network.

A backup battery can supply additional energy to the solar generator if you use solar. The generator can keep your house running.

In some cases, it also can be an alternative to a net metering program or extra storage capacity to run alongside it.

If you rely on grid energy, backup batteries act like oversized power banks. Depending on the capacity, you can plug in appliances, electrical devices, and more. 

It also can allow you to make a real dent in your home energy bills if you draw from your stored power when grid costs are at their highest during times of peak demand.

How Much Does a Home Battery Backup System Cost?

Prices for home backup batteries usually range from $300 to $4000, depending on the battery type, power output, and capacity.

Always look beyond the base cost and consider capacity, output, longevity, and maintenance. It is probably fair to say that although lithium-ion batteries cost more, they do last longer and provide more energy efficiency.

Types of Battery Backup Systems

There are two main types of batteries for home backup solutions: lead-acid and lithium-ion batteries.

Lead Acid

Lead-acid batteries are a low-cost solution for home backup energy. They offer a usable capacity of up to 50% but are popular because they are cheap and robust.

Lithium-Ion

Lithium-ion batteries use cell technology to offer ultra-high charge rate efficiency. With a usable capacity of up to 100%, they let you maximize your energy use. While they are more costly upfront, they are maintenance-free and integrate with solar systems.

Can You Add a Backup Battery to an Existing Solar System?

You can retrofit backup batteries to an existing solar system, but you need to ensure they are compatible with the system.

What to Consider When Buying Home Battery Backup?

Battery Capacity and Output

The total amount a battery can store, i.e., its capacity, is measured in watt-hours (Wh). Depending on your needs, you might find it better to have one larger battery or to stack several smaller ones.

Capacity doesn’t always equal the amount of power a battery can provide. It also depends on the output capacity. 

For example, a high-capacity battery with plenty of storage can have a low power rating or output. This solution is ideal for running several low-usage appliances or devices you want to keep connected for a long time, like a laptop or television.

A low-capacity battery with a high-power rating will be able to manage to run the household, but only for a short period. 

However, generally speaking, the higher capacity a battery offers, the higher its output. If you want a home backup solution, it might be better to have one high-capacity battery or a mix of backup batteries to cover different needs and situations.

Recharging Options

The main decision is whether you want a battery that you can recharge on the grid or solar.

If you lack a solar system, then outlet charging is a must. That said, a battery that recharges using solar panels can be a more reliable solution for those inevitable outages.

Depth of Discharge

You can’t exhaust 100% of a backup battery’s capacity. Indeed, completely discharging a battery shortens its lifespan.

Depth of Discharge (DoD) refers to how much of the backup battery’s power you can use. A higher DoD allows you to access more capacity.

Battery Type

When deciding on the battery type, you’ll want to consider the longevity, cost, and other factors like environmental impact.

Lithium-ion are generally preferred as they have a long lifespan and a high DoD.

Lead acid batteries are another option that is cheap and robust. Unfortunately, they also pose significant environmental risks that can lead to pollution, fires, explosions, leaks, and more.

Compatibility

If you retrofit a solar system, make sure your choice of battery is compatible with your solar system.

Conclusion

For residential solar systems, home battery backups are essential to harvest energy when it is available to store for later use.

Battery backups allow energy independence from the grid and utility providers. They protect against power outages, rising utility prices, and environmental damage.

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