What Are the Different Types of Solar Batteries?
Solar batteries maximize the amount of energy your solar panels produce, reducing your carbon footprint and your solar panel payback period. Plus, solar batteries ensure your home always has electricity—even during power outages.
Because of these benefits, many solar panel owners choose to add a solar battery to their setup. If you’re considering a solar battery, the first step is to understand the different types of batteries you can purchase.
The two most common types of solar batteries are:
We’ll go into more detail about both of these solar batteries and weigh their pros and cons to help you choose the best battery for your solar system. We’ll also share some other solar battery types that are less common but could become more popular in the future.
Interested in adding a backup battery to your solar panel setup? Contact Photon Brothers at 720-370-3344 (Colorado) or 805-351-3371 (California). Our highly-trained solar engineers can help you choose the right backup battery for your home or business.
Lead-Acid Solar Batteries
Even if you’ve never heard of this type of battery, you’ve used it before: Lead-acid batteries are widely used in cars, boats, emergency lights, and a host of other appliances. In fact, lead-acid batteries have been around for over 100 years, making them the oldest type of rechargeable battery available.
Lead-acid batteries store electrical energy via chemical reactions between lead, water, and sulfuric acid. Solar lead-acid batteries are “deep charge” batteries because they are designed to draw power slowly and evenly, discharging over long periods.
In solar energy systems, several lead-acid deep charge batteries are linked together to form a large energy bank. The number of batteries in the bank your solar energy system’s size (measured in kilowatt-hours).
Pros of Lead-Acid Batteries:
- Less expensive: The biggest advantage to lead-acid batteries is that they have lower upfront costs compared to other types of solar batteries.
- Easy to recycle: Lead can be recycled without degrading its properties, which makes lead-acid batteries more sustainable.
Cons of Lead-Acid Batteries:
- Some types require regular maintenance: Some types of lead-acid batteries (called “flooded” batteries) will require you to add distilled water every 2–4 weeks to replace water that’s lost during the charging process.
- Takes up more space: Lead-acid batteries are bulky, which means they will take up more space than other types of solar batteries. It’s also important to note that flooded lead-acid batteries must be installed upright and in a well-ventilated area to ensure proper operation.
- Shorter lifespan: Lead-acid batteries have a shorter lifespan than other solar batteries, lasting anywhere from 2–7 years.
Lithium-Ion Solar Batteries
Lithium-ion batteries are not as old as lead-acid batteries, but today they are almost as ubiquitous. Lithium-ion batteries are found in cell phones, wireless headphones, toys, and all kinds of consumer electronics. Notably, lithium-ion batteries are also used in electric vehicles, which paved the way for their use in solar energy systems.
Lithium-ion batteries work by moving ions (particles that have gained or lost an electron) between two lithium compounds, the anode and cathode, found on opposite sides of the battery. The movement of ions from one side to the other discharges electricity or stores it, depending on the direction of the flow. Solar lithium-ion batteries contain additional electronics that help the batteries operate safely and efficiently.
Note: One of the most popular lithium-ion solar batteries is the Tesla Powerwall, which you can learn more about by visiting our Telsa Powerwall installation page.
Pros of Lithium-Ion Batteries:
- Longer lifespan: Lithium-ion batteries have a lifespan ranging anywhere from 10–15 years—double the lifespan of a lead-acid battery.
- Greater storage capacity and depth of discharge: Compared to lead-acid batteries, lithium-ion batteries have a higher storage capacity, which means they typically take up less space. Lithium-ion batteries also have a higher depth of discharge (DoD) rate, which refers to a battery’s usable storage capacity. A higher DoD rate means a lithium-ion battery can store and provide more power than a similarly-sized lead-acid battery before needing to be recharged.
- No maintenance required: Unlike flooded lead-acid batteries, lithium-ion batteries do not require regular maintenance to operate.
Cons of Lithium-Ion Batteries:
- More expensive: Lithium-ion batteries cost more upfront than lead-acid batteries. However, their longer lifespan often justifies the higher price tag.
- Can pose a fire hazard if not installed correctly: If a lithium-ion battery is installed incorrectly, it has the potential to overheat and start a fire. Most leading solar lithium-ion battery manufacturers include built-in safety devices to prevent overheating. Purchasing a battery from a reputable manufacturer and hiring a solar professional to install the lithium-ion battery correctly will significantly reduce or eliminate the risk of a fire hazard.
Other Types of Solar Batteries
Lead-acid and lithium-ion batteries are the most commonly used solar battery backup options today. However, a few other types of solar battery technologies may increase in popularity as they become more affordable down the road.
Additional types of solar batteries include:
Like their name suggests, saltwater batteries rely on a liquid saltwater solution to store and discharge electricity. This makes saltwater batteries very environmentally friendly and safe to operate. However, saltwater batteries are bigger than other types, making them more expensive to manufacture. For that reason, saltwater batteries are not as commonly used as lead-acid or lithium-ion batteries in residential solar energy systems.
Flow batteries pass ions back and forth between two large tanks filled with liquid electrolyte solutions to store electricity. These non-hazardous batteries boast an impressive 100% DoD rate, which means you can drain all of the battery without damaging it. However, residential solar flow batteries are still in the early stages of development, and many require rare materials (like vanadium), which makes them very expensive.
As their size and manufacturing costs get smaller, we may see flow batteries become more popular for residential solar energy systems in the future.
Have More Questions About Solar Batteries? Call Photon Brothers Today.
Picking a solar battery by yourself is tricky. At Photon Brothers, we simplify the decision-making process by providing genuine recommendations and honest pricing. Call us at 720-370-3344 (Colorado) or 805-351-3371 (California) for expert advice on the best solar battery for your solar panel system.