Solar Energy Battery Storage

power on with solar

Are you concerned with keeping the lights on after a power failure? Or want to reduce your dependency on your utility when the sun goes down? Then you may want to consider installing a solar energy battery storage system. While it can be a great option, they recharge with solar energy, which is free, and they are much more environmentally friendly than a gasoline or diesel generator.

As far as which type of batteries are right for you, there are different types of batteries than can fit your energy goals and budget. The three main types are: Lead-Acid, Lithium-Ion, and Saltwater. They each have their advantages and disadvantages and Royal Solar can help you decide which is best for your situation.

Battery Basics


Capacity is the amount of electricity that a solar battery can store, which is measured in kilowatt-hours (kWh). Home solar batteries are designed to be stackable, which means you can have multiple batteries in your system to increase storage capacity.

While capacity tells you how large your battery is, it doesn’t tell you how much power a battery can provide at any given time. You also need to consider the battery’s power rating. For most batteries, a power rating is the amount of electricity a battery can deliver at one time, and it’s measured in kilowatt hours (kWh).

A battery with a high capacity but a low power rating will deliver a low amount of electricity, probably enough to run a few crucial appliances (your refrigerator, for instance), for a long time. A battery with low capacity and a high-power rating could probably run your entire home, but only for a short time.

Depth of Discharge

Batteries need to retain some charge at all times due to their chemical composition. If you use 100% of your battery’s charge, it will significantly reduce its useful life. Depth of discharge (DoD) refers to the amount of a battery’s capacity that’s been used. The battery’s manufacturer will specify the maximum DoD for optimum performance. For example, if you have a 10-kWh battery, you shouldn’t use more than 9 kWh of the battery’s power before recharging it. In general, the higher a battery’s DoD, you can use more of its capacity before recharging.

Round-Trip Efficiency

Round-trip efficiency is the amount of energy that can be used as a percentage of the total amount of energy needed to store it. For instance, if your solar panels sent 10 kWh of electricity to your battery, and you can only use 8 kWh of that energy, that means 2 kWh of that energy was used by the battery’s operating system to store and release the electricity, which makes the battery’s round trip efficiency rating 80%. High efficiency batteries will save you money in the long run since you’ll be able to use more of the electricity for your appliances rather than being used to store the electricity.

Battery Warranties

Your battery’s warranty will give you good idea of how long the battery will last. Most solar batteries have a lifespan of at least 10 years with regular use.

Battery Life

We’re sure you’ve got a laptop, cell phone, or other device where the battery performance has declined over time. This is normal, since with each discharge/recharge cycle, its ability to hold a charge decreases. Most warranties guarantee a battery for a specific time period.

Types of Solar Storage Batteries

Lead-Acid Batteries

Lead-acid batteries have been around for over 100 years. It’s the kind of battery you’ll find in your car and they’ve been used for off-grid solar systems for several decades.

They come in different types – Wet-Cell or Flooded Lead Acid, Gel Cell, and Absorbed Glass Mat (AGM) batteries. They usually take a lot of room and aren’t as efficient as lithium-ion batteries.

Lithium-Ion Batteries

Lithium-ion have become the most popular method of solar energy storage and are rapidly improving and becoming more affordable since electric vehicle companies are working on making them last longer. They’re more expensive than lead-acid but have a longer lifespan and only take a small space by hanging on a garage wall.

Saltwater Batteries

Saltwater batteries (or sodium batteries) use salt to produce power. They can produce power over a long duration and are non-toxic, which makes them a safer alternative. Unlike lithium-ion batteries they can be drained. Refilling is messy and complicated and they take up a lot of space.

Which Battery is Right for Me?

Each battery type has its pluses and minuses. But a lithium-ion battery is the most practical, space-saving, and clean energy storage unit. Which comes closest to meeting your needs is something you’ll need to discuss with your Royal Aire consultant. We’ll go over your options and help you decide which storage system will meet your energy needs and fit your budget.