How Many Solar Batteries Do You Need to Power a Home?

As net metering policies face challenges and grid outages become more common and prolonged, the advantages of combining battery storage with solar panels are growing.

But how many solar batteries are needed to run a home? Several factors influence this, such as your energy objectives, the kind and size of batteries you choose, and the load size you intend to supply power to.

How many batteries do I need for solar?

For homes connected to the grid, usually, 1-3 lithium-ion batteries with at least 10 kWh of capacity are required to achieve savings through load shifting, provide emergency power for crucial systems, or offer comprehensive backup power.

A 2022 report by Lawrence Berkeley National Laboratory found that a solar setup designed to offset 100% of a household's energy needs, paired with a single 10 kWh battery, can sustain essential home systems for three days across almost every region in the U.S. and throughout the year. If the backup plan includes heating and cooling, then the household will need a larger setup with 30 kWh of storage, equivalent to 2-3 lithium-ion batteries, to cover 96% of their electrical needs.

The number of batteries your home might need primarily hinges on your specific energy goals. Now, let's explore the number of solar batteries required to achieve the three most popular energy objectives.

Goal 1: Saving Costs Through Load Shifting

In regions where net metering policies are either not beneficial or absent, utilizing battery storage becomes a key strategy to enhance the cost-effectiveness of residential solar systems. For instance, with the introduction of California's NEM 3.0 Solar Billing, storing your solar-generated electricity for later use (known as load shifting) has become significantly more economical than sending it back to the grid for minimal returns.

For those primarily focused on load shifting to avoid high time-of-use rates without the necessity for backup power, a consumption-focused battery ranging from 6-10 kWh is usually adequate. This is because the aim is to have sufficient storage capacity to sidestep the need to purchase electricity from the grid during peak pricing periods.

What defines a consumption-only battery?

A consumption-only, or "no-backup," battery represents a modern class of energy storage designed for load shifting within solar power setups, without the ability to offer backup power during grid failures. Lacking the components, software, and installation efforts necessary for backup functionality, these batteries are priced approximately two-thirds lower than standard backup batteries. This cost efficiency makes them an attractive option for users prioritizing energy cost savings over emergency power supply.

Goal 2: Powering Essential Systems During Outages

A primary and well-understood benefit of integrating solar panels with battery storage is the ability to maintain power during grid failures.

Solar panels alone must be deactivated during outages to protect utility workers from the risk of electrical backflow, leaving homes without power. By incorporating battery storage, not only can you save energy for use in the evening or during outages, but you also enable your solar system to continue operating and generating power when the grid is down.

Typically, home battery systems are set up to supply power to essential household functions, such as lighting, internet connectivity, televisions, medical equipment, refrigeration, and kitchen appliances. Research by the Berkeley Lab indicates that a solar setup designed to cover 100% of a home's yearly electricity needs, coupled with a single 10 kWh battery, is capable of powering these critical systems for three days during outages in most areas of the US.

Additionally, while backup batteries offer the potential for energy cost savings through load shifting, the initial cost for backup capabilities may result in a longer period before investment returns are realized.

Goal 3: Complete Home Power Backup

To keep your entire house powered during grid failures, you'll likely need at least three lithium-ion solar batteries. This setup is essential to handle the high energy requirements and power spikes from heating, air conditioning, laundry appliances, electric water heaters, and potentially electric vehicle (EV) charging.

For example, merging three 13.6 kWh Franklin Home Power batteries can yield 40.8 kWh of available energy and 15 kW of constant power, sufficient to support the average household fully.

It's important to remember that achieving a whole-home backup capability necessitates extra solar panel capacity to replenish the increased battery storage. Research by the Berkeley Lab suggests that a substantial solar array with 30 kWh of battery storage can, on average, supply 96% of a household's essential energy needs, including for heating and cooling, over a three-day outage.

How to Optimize Your Solar Battery System

While it’s essential to have enough solar batteries to meet your energy needs, it’s also crucial to ensure that your system is optimized for efficiency. Here are a few tips to help you make the most of your solar battery setup:

Solar Panel Sizing: Ensure that your solar panel system is adequately sized to generate enough energy to recharge your batteries. If your panels generate too little energy, your batteries will not be able to charge fully, leaving you without enough power.

Battery Management System (BMS): A BMS helps to monitor the health of your batteries, ensuring that they are operating within safe parameters. This is especially important for lithium-ion batteries, which can be damaged by overcharging or discharging.

Regular Maintenance: Just like any other system, regular maintenance is necessary to keep your solar battery system running efficiently. Check for signs of wear and tear, and ensure that all components are functioning properly.

Additional Tips for Going Solar

Consider Hybrid Systems: If you don’t want to rely entirely on solar batteries, you can opt for a hybrid system that includes both solar panels and a connection to the grid. This allows you to draw power from the grid when your batteries run low, while still saving on energy costs by using solar energy during the day.

Incorporate Energy Efficiency: To reduce the number of batteries needed, consider improving your home’s energy efficiency. Upgrade to LED lights, invest in energy-efficient appliances, and seal drafts to reduce your overall energy consumption.

Explore Financing Options: Solar battery systems can be a significant investment, but many financing options, tax incentives, and rebates are available to help offset the initial cost. Be sure to explore these options before making your decision.

Creating Your Own Battery Storage Solution

The role of battery storage in creating a resilient and cost-effective home energy system is increasingly important. The specific number of batteries required for your setup hinges on your unique energy objectives, the amount of storage necessary, and the characteristics of the bat

Powering Your Home with Innotinum’s Integrated Energy Storage Solution

For those considering the step into solar battery storage, Innotinum offers an all-in-one energy storage system that can streamline the process. Our comprehensive system, which includes a battery storage system complete with a control box and BMS (Battery Management System), as well as a hybrid inverter, is designed to meet various home energy needs efficiently.

Innotinum’s system simplifies the decision of how many batteries are needed to power a home. With scalable solutions that can be tailored to fit your energy objectives, whether it’s cost-saving through load shifting, emergency power during outages, or complete home backup, our technology ensures you have the right amount of power when and where you need it.

Dive into a future of energy independence and resilience by exploring Innotinum’s all-in-one energy storage system at Innotinum Residential ESS. Discover how our integrated approach can serve your household's unique energy demands.