Solar Panel batteries shown.

How To Choose The Best Solar Batteries For Your Home


Using a solar panel system is a great way to power your home through renewable energy – as long as your system is running efficiently. When your system isn’t able to generate power, like at night, during a power outage or due to an operational issue, you’ll need to have a backup power source in place. Thanks to advancements in technology, homeowners can purchase solar batteries with enough capacity to keep all their home electronics up and running.

If you’re thinking of adding a solar battery to your home, you’ll want to keep a few considerations in mind. Let’s take a look at what solar batteries are and how to choose the right one for your home’s solar power system.

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What Are Solar Batteries?

Essentially, a solar battery device is designed to complement your solar power system by storing excess electricity generated by your panels. You can then use this extra energy to power your appliances during times when your panels can’t harness more power. Solar batteries are particularly beneficial and necessary for homeowners with off-grid solar systems.

What To Look For In Solar Panel Batteries

Not all solar batteries are created the same. This is why it’s important to do your research on the features and benefits of each type of solar battery before choosing one.

Here are six measurements you can use to select a battery that will work for your solar panel system.

1. Battery Type

One of the first items you’ll want to ponder is the type of battery that will work best with your system. There are three main types of solar batteries available:

  • Lead-acid: Composed mostly of lead, these types of batteries are the oldest form of battery technology. Lead-acid batteries tend to take up a lot of space, and unlike some other types of batteries, they’re not capable of discharging at full capacity.
  • Lithium-ion: This type of battery has only been around since the 1980s, but it’s quickly become the most common form of battery technology. The chemical makeup of lithium-ion batteries allows for greater power density and longevity.
  • Flow batteries: Flow batteries are less popular than lithium-ion and even lead-acid batteries, but they may soon become a popular choice for solar energy storage. Though less power dense and larger in size than the lithium-ion battery, these batteries can hold a significantly longer charge.

2. Power

You’ll want to evaluate a battery based on the kilowatts (kW) of power that the battery can output. The power rating helps you determine the number of systems and appliances you can power simultaneously with the battery. Keep in mind, however, that not all appliances use the same amount of power.

A typical battery output will be around 5 kW and come with both a continuous and instantaneous power rating. These two ratings show you the power output the battery is capable of emitting during continuous use and short power bursts.

3. Size And Storage Capacity

Another factor to consider is the storage capacity. This refers to the amount of electricity that a battery can store, and it’s expressed in kilowatt-hours (kWh).

While the power rating can help you determine how much power a battery can supply, the storage capacity can help you determine how long a battery can power your home’s electricity. Keep in mind that the more power you’re using, the shorter your battery lifespan, so you can’t always judge a battery’s storage capacity based on its size. The more appliances you have the battery powering, the faster your battery life will deplete.

The number of solar batteries needed to power a house will depend on your average energy usage per day and the efficiency of the battery you’re considering. It’s sometimes better to overestimate the number of solar batteries you’ll need for your home since each one will decrease in efficiency as it ages.

4. Round-Trip Efficiency

The round-trip efficiency rating determines how well a battery system (which includes the inverter and battery) can successfully convert and reuse the energy that it’s storing. Essentially, this refers to the percentage of direct current (DC) energy that can be placed into storage to be retrieved later.

With a higher round-trip efficiency, less energy is wasted in the storage process. Typically, most batteries can handle an 80% round-trip efficiency.

5. Battery Lifespan

The next feature of a solar battery worth considering is the battery’s life expectancy. Battery lives are expressed in one of three ways:

  • Expected years of operation
  • Expected throughput
  • Expected cycles

The throughput of a battery is a measure of how much energy can move through the battery over its lifetime, and expected cycles are how many times you can charge and discharge a battery over time.

6. Safety

Government standards require a battery to meet a set of safety requirements before it can be certified as an acceptable product for installation. Some batteries may be held to higher safety standards than others if the manufacturer requires testing and regulation beyond the required government standards. In good news, this certification means that you won’t find any solar batteries on the market that are considered unsafe.

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How Much Do Solar Batteries Cost?

Most batteries are priced based on kWh. On average, you can expect an uninstalled solar battery to cost $400/kWh – $750/kWh. With the purchase of a solar battery and labor fees, the total cost of a solar battery installation might be anywhere between $300 – $15,000.

However, a variety of factors determine the cost of a solar battery. These include:

  • Chemistry
  • Size
  • Manufacturer
  • Incentives or rebates
  • Number of batteries being installed
  • Labor costs

For example, it’s typically true that the larger the battery size, the higher the cost. The cost will also increase with every additional battery that you need to purchase for your home’s solar power system and the load that the battery is capable of producing. Keep this in mind when selecting the right battery for your home.

The Bottom Line: Choose The Best Solar Battery For You

Solar batteries are beneficial to have in times when your solar panel system can’t operate at full efficiency. Choosing the right one, however, can be difficult, thanks to an abundance of options on the market and several factors to consider while shopping.

Have questions about how to find the right solar battery for your home? Contact a Rocket SolarSM Advisor today for assistance.

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