FAQ

Why would I want a home battery?

A home battery is the missing piece to the home energy equation. Like the landline before the cellphone or the desktop computer before the laptop, the home has remained tethered to and dependent on the energy grid, until now. A home battery provides energy independence, by powering your home even without the energy grid, like during a power outage. When paired with solar panels, you can even go off the energy grid. And on a daily basis, a home battery can make you money by optimizing when you use energy, by charging when energy is cheap and discharging when it’s most expensive. In short, a home battery has many different benefits. Swell is here to give you the information you need to decide whether a home battery makes sense for you.

How many people have home batteries?

There are tens of thousands of home batteries in the United States, but the vast majority are old, bulky lead acid batteries used for off-grid cabins. At Swell, we specialize in the new generation of smart, compact, and powerful home batteries that use the same advanced lithium-ion battery technology used in electric vehicles like the Tesla. The new generation of smart home batteries entered the U.S. market in 2015, and there are only a few thousand installed today. Swell is the leading provider of all the best smart home batteries and is facilitating a rapid growth in installations. In other countries, advanced home batteries are already becoming commonplace. In both Japan and Germany, for example, there are over 30,000 home batteries already operating today.

Do I need solar panels to have a home battery?

No. A home battery functions without solar panels by charging from the energy grid. Without solar panels, a home battery can power your home for up to 24 hours, but it can be sized to provide more or less power, depending on your usage. A home battery can also save you money every day by charging when electricity is cheapest, and discharging when it’s most expensive. Finally, home batteries can make you money, even without solar panels, by providing valuable energy grid services to the energy company.

How long can a home battery power my home during a power outage?

Theoretically, a home battery can power your home until the end of time, when paired with solar panels. Solar panels power your home during the day and recharge the battery, and the battery powers your home at night. Without solar panels, the duration of power will vary depending on the size of your battery and how much energy you use. In general, we advise homeowners to size their system to provide at least 12 hours of backup power.

Aren’t home batteries more expensive than backup generators?

Traditional generators are cheaper upfront, but with ongoing maintenance and fuel costs, a home battery is usually more cost effective over the long run. For example, traditional fossil fuel generators require constant supply of natural gas, diesel, or propane, and yearly maintenance to keep all the moving parts working. Service agreements for standby generators can exceed $1000 per year. A home battery requires no fuel or planned maintenance. Moreover, all home batteries purchased through Swell come with a 10 year warranty, and, when they are part of the Swell ESA (Energy Services Agreement), the entire system, including batteries, are warrantied for the full 25-year duration of the ESA. This is far longer than the length of warranties for traditional generators.

Finally, home batteries are simply a better backup power source. They are automatic, silent, and clean, and when paired with solar panels, they provide backup power through even the longest outages.

Can I save money with a home battery?

Absolutely. A home battery can pay for itself in just a few years in certain areas of the country. Whether and how much money you can save depends on where you live. In some areas, electricity prices are much higher during certain periods of the day, and a home battery can charge when electricity is cheap and discharge during those peak rate periods, saving you money every day. In other areas of the country, a home battery can enhance the value of solar panels and save you even more money than solar panels alone.

Can I make money with a home battery?

Totally. A home battery can not only save you money, but it can make money for you by providing valuable services to the energy grid. We can enroll you in programs that will pay you to let Swell discharge the battery when you don’t need it and the energy company needs your energy to address grid problems. By providing these “energy grid services,” you help the energy company reduce the use of fossil fuel-powered plants and increase the use of clean energy, like solar and wind. And you get paid, all without changing your energy usage.

Will I still get paid for solar energy I sell to the energy grid through net metering?

Yes. A home battery does not affect net metering or the amount you get paid for energy you send back to the energy grid. In some circumstances, a home battery may reduce the amount of energy you send back to the energy grid, because it allows you to store excess solar energy for use when you need it after the sun goes down. But for any energy your solar panels send back to the energy grid, you will be compensated the same as without a home battery.

For how many years does a home battery last?

All home batteries that Swell provides come with a manufacturer warranty of 10 years or more. That means if anything breaks in the first decade, you’re covered. And in reality, home batteries can keep working for 15 years or more.

Even better - when your home batteries are part of a Swell ESA (Energy Services Agreement), your entire system, including batteries, are warrantied for the full 25-year duration of the ESA.

How are Swell’s batteries different?

At Swell, we specialize in the new generation of smart, compact and powerful home batteries that use the same advanced lithium-ion battery technology used in electric vehicles like the Tesla. The new home batteries require no planned maintenance or fuel, and they are compact enough to mount on a wall out of the way, like on the side of your house or in the garage.

What's in a home battery, anyway?

Home batteries include a few key components, the most obvious being a battery. The battery inside a home battery includes several battery modules, which in turn are made of a bundle of battery cells. The battery cells use lithium-ion chemistry to store and release electrical current. The lithium-ion cells are identical to those used in popular electric vehicles. For example, the LG Home Battery uses the same cells that LG provides to Chevrolet for the Volt, and the Tesla Powerwall uses the same cells that Tesla uses in the Model S. In addition to batteries, a home battery contains a battery management system, which controls the charge and discharge of the battery and monitors the health of each battery cell. Some home batteries also include a dedicated inverter to convert DC electricity from the battery into AC electricity for use in the home.

Is the home battery a new concept?

Yes and no. There are tens of thousands of home batteries in the United States, but the vast majority are old, bulky lead acid batteries. Old lead-acid home batteries were only capable of providing backup power and limited off-grid capability. The new generation of smart home batteries is both similar and fundamentally new, like the difference between a smartphone and an old cell phone. New home batteries are similar because they can also provide backup power and off-grid capability. But new smart home batteries are also cloud-connected, compact, long-lasting, and capable of daily cycling to save you money and make you money by providing valuable services to the energy grid.

Are there different sizes of home batteries?

Yes. Home batteries come in several sizes. Most models are modular, meaning that they can be combined to create larger systems. For example, LG’s Home Battery ranges in size from 6 kWh to 18 kWh, in 3 kWh increments. In this way, home batteries are like many of the appliances in your home, from air conditioners to water heaters: they vary in size and can be sized to fit your needs.

What’s the difference between different kinds of home batteries?

Home batteries differ in a few key ways. In addition to size, the cycle life of a home battery is key to understanding its use case. For example, a Sonnen can be cycled 10,000 times, making it great for self-consumption of solar energy over 25 years (approximately the useful life of solar panels). The Tesla Powerwall can by cycled daily for 10 years or more, making it good for self-consumption, time-of-use optimization, and backup power. The difference is key. For example, older lead acid batteries only have 5 year lifespans and require lots of maintenance, while advanced energy storage systems last longer and require no maintenance. Second, some home batteries can only be installed with a new solar installation, whereas others can be seamlessly retrofitted to an existing solar installation. For example, the Mercedes home battery can only be installed with particular solar inverters, and it can only be installed on a new solar installation, whereas the Tesla Powerwall 2 AC can be installed and integrated with a new or any existing solar installation.

Do I need a permit for a home battery?

In most cities, you need a permit to install a home battery. Swell and your Swell-approved installer will handle everything for you, including obtaining any permits you need from your city or energy company. All you have to do is sit back and relax.

Where are home batteries made?

Home batteries are made by a variety of companies, including manufacturers based in Korea, Japan, Germany, Canada, and California.

Can I add a home battery to an existing solar installation?

Yes, but not just any battery. Some home batteries can only be installed with new solar installations, whereas others, like the LG Home Battery, can be installed with new or any existing solar installation.

Can I install a home battery myself?

Home batteries require installation by a licensed electrician. If you’re not a licensed electrician, we can recommend a Swell-approved installer to handle the design, permitting, installation, and maintenance of your system.

Who installs my home battery?

Swell trains and supplies home batteries to local installers. When you choose to get a home battery through Swell, we’ll connect you with a Swell-approved installer who we have trained to design, permit, and install your home battery. Our installers tend to be experienced, certified solar installers and electricians from your neighborhood. You may already know them, but if not, we’re glad to provide you options and give you any information you need to choose the best one for you.

What is involved in the installation?

A home battery installation is relatively simple. The battery itself is mounted on the wall or on the floor near your main electrical distribution panel. The appliances and rooms that you want to backup are then rewired from your main distribution panel to a critical loads panel adjacent to the battery. If you have solar panels, they are also rewired to the critical loads panel. The battery is then connected to the energy grid through the main panel, and to the critical loads and solar panels (if any) through the critical loads panel.

How much does installation cost?

The cost of installation will vary significantly from house to house, depending on the type and size of your home battery, the amount of electrical work required to backup your critical loads, and other factors. The cost of installation includes labor and other components, including the critical loads panel, disconnects, wires, and other materials. In general, installation costs begin around $1,000.

How long does installation take?

Generally, installation lasts between a half and full day.

Is there a service agreement?

Yes. Swell offers a service agreement that provides peace of mind and ensures your home battery performs as it should. Swell’s service agreement provides: backup power service, remote monitoring, reporting and alerts, incentive compliance, maintenance support, and the ability to participate in energy grid services.

How much does a home battery cost?

Different types and sizes of home batteries vary in price from a few thousand dollars up to tens of thousands of dollars. In general, a smaller capacity battery with lower cycle life is more affordable than a larger battery with a longer cycle life.

Want to get a home battery for your residence?