Tips Before Buying a Solar Battery

Shopping for a solar battery (or any energy-related product) can be confusing. There are a ton of different specs and metrics, and it’s often hard to tell which options make sense for your home.

Here are some of the most common questions we get about solar batteries, and our answers:

Are Batteries for Solar Worth It?

Solar batteries are a smart investment for most solar energy users, especially those who want to go off the grid. They are recommended for residential energy storage, DIY solar projects, and many other uses.

You can use your solar batteries to store the extra energy your system generates during the day. That way, it’s there when you need it at night or on cloudy days. Your batteries will also come in handy during power outages.

Storage systems for solar are an energy-efficient source of backup power for many people. However, they tend to pay off more in the long run — in the short run, a propane or natural gas generator may be cheaper.

How do battery storage systems work with solar panels??

You can install battery storage right alongside your solar panel system to store any excess energy produced. Then when your panels aren’t producing energy, such as at night or on days with less-sunny weather, you can use the energy stored in the battery instead. You may need to buy an inverter to convert the stored DC power in the batteries to the AC power you need for your home.

Not all residential solar panel arrays require battery storage. However, we often recommend them for homeowners depending on their energy needs and goals. In most cases, we recommend storage for reliable backup power protection in an outage.

A battery storage system can also reduce your carbon footprint, lower your utility bills, and even help you go off-grid, depending on the battery storage system chosen for your installation..

Batteries self-discharge over time, meaning the energy will deplete a little bit each month if it is not used. Newer batteries may deplete 1-2% per month, while older batteries may deplete the same amount over the course of a week. You may need to take self-discharging into account if you plan to store energy for long periods of time.

How Long Do Battery Storage Systems Last?

A fully charged solar battery should be able to power a home for 12 to 24 hours on average. Typically, a solar battery will last up to 15 years and most manufacturers offer a 10 year warranty.

Factors like the capacity of your battery system, your household’s energy consumption, and whether or not you are connected to an electrical grid affect how long your solar battery can provide continuous power. You can help your solar battery last longer with proper maintenance and protection from extreme weather conditions, including extreme temperatures. For that reason we always recommend having the batteries installed in the garage, but if they have to be outdoors, keeping them out of direct sunlight is best.

How Do I Choose the Right Solar Battery Bank Size?

Are you wondering if you can store the excess energy that your solar system generates and save it for when you need it? 

You can do it with solar batteries. 

Solar batteries come in a variety of shapes and sizes, but all of them serve one crucial function: 

To store excess solar energy generated during sunny weather to be used during cloudy days, overnight, or even during power outages. 

This blog will help you decide which solar storage solution is best for you. 

The solar battery storage market is booming.

The residential market has seen a boom in solar storage purchases in recent years.

Batteries have long been considered an optional technology by homeowners. Storage has been a cherry on top of solar systems powered by solar panels and inverters.

Between this and budgetary reasons (battery costs are decreasing), the storage market has taken longer to build up the momentum solar panels have developed over the last two decades. 

No longer!

California and Texas have consistently led the charge on solar technology, and they are showing explosive growth in the storage market. This projects a future of lower prices, more product availability, and favorable legislation. 

Let's look at the numbers: 

• In 2020, only 6% of residential jobs included batteries. 

• Texas plans to include storage in 42% of its projected 7.7 GW of solar projects this year, which will account for 1 ⁄ 4 of the nation's solar. That's a considerable jump from the 27% of projects that included storage in 2022. 

As we keep an eye on the future of storage here in the U.S., here are the top things to consider to make an informed decision about your upcoming solar storage purchase: 

Lithium-ion batteries for residential projects

Lithium-ion, lead acid, and flow batteries are the most common types of batteries used in residential projects, with lithium-ion leading the pack by a wide margin. Tesla Powerwall and Generac Pwrcl lithium-ion batteries have become increasingly popular over the last decade. 

The reason lithium-ion batteries are the top choice for residential projects is that they feature:

Limited maintenance requirements

Deep-cycling capabilities, being tolerant of 80-100% depth of discharge. With the newest technology self-recharging, you won't have to worry about being without your battery due to lost charge.

Extended lifespans generally lasting up to 15 years or 3,000-5,000 cycles. With panels lasting 25-30 years on average, you may only need to replace each battery once for the life of your system. 

Wide temperature tolerance: A Powerwall holds up from -4 to 122 F. Batteries should be located near your inverter, which is most likely in your garage. They'll likely stay in this safe range for their lifetime. 

High energy density refers to the amount of energy stored in a region of space. Tesla Powerwalls, for example, are about 63"*30"*6" and store a whopping 13.5 kWh of energy. Considering the device takes up less space than a refrigerator and is hung on a wall, it's pretty convenient. 

Why you might want to pass on lead acid batteries 

Deep cycle batteries are best suited for off-grid living situations or as additional power storage for boats or recreational vehicles. 

They are cost-effective, running from $300- $600. Deep cycle batteries are also tried and true technology, having existed for over a century.  But they also have a low energy density, which means you'll need more of them to power your home, and they take up real estate. They have a shorter life cycle compared to other battery types. And they require regular maintenance. 

Unless you're doing a DIY or off-grid installation, these likely aren't the right fit for your project. 

Flow batteries for residential projects may be the future.  

Flow batteries are a more recent technology with a higher price tag than lithium-ion batteries and a lower energy density. Unlike traditional batteries, where the energy is stored within the battery cell, flow batteries store energy in two separate electrolyte tanks. These tanks connect to the power generation unit via a network of pumps and pipes.

While they are not yet widely used in the residential market due to a higher price point, we see a place for them in the future.

These batteries offer several advantages for residential solar projects:

Scalability: The battery's capacity can be increased by adding more electrolytes to the tanks, allowing homeowners to adjust their energy storage capacity based on their needs.

Long-term storage: Flow batteries are well-suited for long-duration energy storage. Since the energy is stored in external tanks rather than within the cells, larger amounts of energy can be stored over more extended periods.

Long cycle life: Flow batteries generally have a longer cycle life (up to 20 years) than conventional batteries. They can endure many charge and discharge cycles without significant degradation, making them suitable for daily use in residential solar projects.

Excellent safety profile: Flow batteries use non-flammable electrolyte solutions, reducing the risk of fire or explosions. 

As you evaluate which type of battery is best for your project, you'll want to consider the following tips:

7 Tips To Choose the Right Solar Batteries for Energy Storage

Assess Your Energy Needs

Calculate your average daily energy consumption here by accounting for the appliances, electronics, and other devices you will power with solar energy. You can also run some calculations directly on our site. 

Consider your household's energy usage patterns. Do you typically consume more energy during the day or at night? Understanding when and how much energy you use will help determine your battery's discharge and recharge rates.

Evaluate Battery Capacity

Battery capacity refers to the amount of energy a battery can store. The average solar battery has a capacity of about 10 kWh. You've already calculated your energy consumption above. To determine the required capacity of your project, consider the size of your solar panel system, desired backup power during outages, and the amount of energy you typically consume. Aim for a battery capacity that allows you to store enough energy to meet your needs while considering the cost and available space for installation.

Consider Depth of Discharge

Depth of discharge (DoD) refers to the percentage of a battery's capacity that can be used before recharging. Some batteries have higher DoD levels, allowing you to utilize more of their capacity. Lithium-ion batteries generally have high DOD levels, which is why they are so popular for solar projects. 

Evaluate Efficiency

Similarly to solar panels, battery efficiency is an essential factor to consider. Look for batteries with higher efficiency ratings, as they will maximize the usable energy from your solar system and minimize wastage.

Efficiency determines how much of a battery's charge is lost during a cycle. Lithium-ion is the winner at nearly 100%, deep cycle batteries come in around 85-95%, and flow batteries range from 70%-85%. 

Lifespan and Warranty

Consider the lifespan and warranty offered by the battery manufacturer. A longer lifespan ensures you recoup your investment, while a comprehensive warranty provides protection and peace of mind.

You can expect a 10-year warranty on lithium-ion batteries. You might see anywhere from 2-10 years on deep-cycle batteries. Flow batteries are touting 20-25 year warranties. 

Installation and Maintenance

Assess the installation requirements and maintenance needs of the battery. Some batteries may require specific conditions or additional equipment, such as inverters or charge controllers. Understand the installation process and ongoing maintenance requirements before making a decision.

Budget and Cost Analysis

Determine your budget for the solar battery system, including installation costs. Compare the prices of different battery options, factoring in the capacity, lifespan, warranty, and overall value for money. Consider long-term savings on energy bills and potential incentives or tax credits link to tax credit blog available for solar energy installations. 

Get it right with Yellowlite.

When choosing the correct battery for your project, it helps to consult with experienced solar experts like the ones here at Yellowlite. We can assess your situation, provide personalized recommendations, and help you make the right choice. 

If you have any questions or want help choosing your solar battery, contact our sales team here.