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How Many Batteries Are Needed to Power a House?
The amount of battery storage required is based on your home's energy usage. Energy usage is measured in kilowatt-hours over some time—for example, a home requiring 1,000 watts for 10 hours per day = 10 kWh per day. When calculating, you need to consider the battery's performance and how much continuous output you require. It's essential to consult with a solar energy professional to size the panels and batteries for your needs properly.
Are Lithium Batteries Better Than Lead Acid?
It would take several lithium-ion batteries to power a home for a day or more. Lead-acid batteries, which have been around for decades, are less efficient, offer less storage, are often larger, and do not last as long. Lithium batteries can be left at a partial charge without any adverse effects.
Which Home Battery Is Right for Me?
While battery technology is still in its infancy, a breakthrough came with lithium-ion batteries. These batteries–the same kind found in cell phones and many other devices–capture energy from solar panels as direct current (DC) and convert it through an inverter to alternative current (AC), the kind used in American homes.
Several flavors of battery storage exist: DC-coupled systems, AC coupled systems, AC battery systems, and hybrid converter systems. Considering the complexity of the options, ask your battery installer which system will work best with your solar array and the infrastructure of your local utility.
Generally, AC battery systems such as the Tesla Powerwall 2 and the Enphase Battery are popular with homeowners who have no desire to live off the grid. The AC coupled systems offer affordability and ease of installation. In addition, the more sophisticated hybrid converter system, such as LG Chem RESU, allows for high voltage lithium batteries.
Batteries can be sized to serve the size of your home and your solar arrays. A larger home may need a larger battery. Again, consult a clean energy expert and electrician to ensure the sizing works and the system will meet your expectations.
How Much Is a Solar Home Battery?
Home battery prices below do not include installation, which can range from $2,000 to nearly $20,000 for one or more batteries. It’s not a purchase every solar array owner needs to make. Still, for those looking to be on the cutting edge of innovation or live in areas where utilities have creative rate structures, a battery could be a wise investment.
What Are the Best Home Battery Options?
While it's difficult to compare models, we've taken the extra step to look at the price per kilowatt-hour (kWh). For context, the average U.S. home uses about 30 kWh per day.
Nissan XStorage
The auto manufacturing giant Nissan has a solar backup battery option called the Nissan XStorage. This battery comes in three different sizes. The 4.2 kWh system costs $3,700, while the broadest choice of 9.6 kWh costs just under $10,000. Many of these battery options are factory refurbished electrical vehicle batteries giving a useful second life to the millions of EV batteries produced in the coming years.
Nissan XStorage Specs
- Power range from 3.6 kW to 6 kW
- Nominal capacity from 4.2 kWh to 10.08 kWh
- Can be wall or floor mounted
- 5 to 10-year warranty depending on model
- Stocks both grid and renewable energy during the day
Frank Jossi
Based in St. Paul, Frank Jossi is a journalist, editor and content strategist. He covers clean energy in Minnesota for Midwest Energy News and writes frequently for Finance & Commerce. His work has appeared in more than 70 local, national and international publications.