The blog below is all about lead acid batteries for solar storage, which can be a good option if you’re looking to store energy generated by a solar array.
Currently available solar battery storage options most frequently use lead acid batteries. Most often, you’ll see a rural home installing a bank of lead acid batteries along with solar panels because it’s less expensive than shelling out $30,000 to have the grid extended all the way to their home.
This article will look at how to keep your battery healthy and, for those who are still considering purchasing, what information you need to know when selecting your lead acid solar battery.
Lead-acid Solar Batteries
Lead-acid solar batteries have sulphuric acid as their electrolyte and lead electrodes. Being in use since 1859, they are the most traditional battery type. They are utilized in houses, mobile towers, cars, and more.
The oldest solar battery type is lead-acid, which also has one of the shortest market life spans. Lead-acid batteries have a cycle life of 1500–3000 cycles or roughly three–five years. Here is a guide to the types of lead acid batteries.
Different Types of Deep-cycle Lead Acid Batteries for Solar
Where the rubber meets the road is right here. Deep cycle lead acid batteries come in three main categories, each with advantages and disadvantages. They include:
The first kind is less expensive and more durable, but it needs maintenance on a regular basis to keep the electrolyte and water inside the battery case in balance.
The other two fall under the broader category of “sealed lead acid batteries”. While they are made to require no maintenance because the electrolyte is sealed inside the case, they are also more expensive and might not last as long.
Flooded Lead Acid Batteries
Flooded lead acid (FLA) batteries are the most straightforward and affordable deep-cycle battery types. The simple lead acid battery depicted below, which has cylindrical lead plates submerged in an electrolyte bath of water and acid, is the battery that most closely resembles these ones.
Although FLA batteries are inexpensive, they require a lot of maintenance because the electrolyte inside the battery case evaporatively over time, necessitating the addition of distilled water on a regular basis. The battery’s lifespan will be significantly shortened if the water isn’t added frequently enough.
FLA batteries must be stored upright and given enough ventilation because they are designed to be opened, in order to avoid a buildup of the hydrogen gas that is released when the battery discharges. This means keeping a bank of deep-cycle FLA batteries suitable for home energy storage can take up a lot of space, as shown in the image above.
FLA batteries can last from 5 to 8 years in a home energy storage setup if handled carefully and regularly discharged to no more than half of their capacity.
Sealed Lead Acid Batteries
As the name implies, sealed lead acid (SLA) batteries are impenetrable and don’t need to have their water refilled.
Instead, they either add absorbent fiberglass separators between the positive and negative plates or turn the electrolyte into a gel in order to keep almost all of the water present in the electrolyte inside the battery body. These designs mean SLA batteries can be placed on their sides and stacked for easy storage.
Despite these advancements, SLA batteries still require venting to avoid the buildup of hydrogen gas. This vent is controlled by a valve, which is why SLA batteries are sometimes also called “valve-regulated lead acid”, or VRLA batteries.
Absorbent Glass Mat (AGM) and gel batteries are the two main types of SLA batteries, as previously mentioned.
- AGM batteries (Absorbent Glass Mat)
When battery manufacturers were trying to figure out how to best keep the electrolyte close to the plates for use in high-vibration applications like golf carts, they created AGM batteries. Read More: Are AGM Batteries Better Than Lead-acid?
The mat in this instance is positioned between the negative and positive plates in each of the battery cells and is made of a fine fiberglass mesh that resembles a gauze pad. An AGM battery can be discharged more deeply while still allowing the sulfate to recombine with the free hydrogen because it nearly completely traps the electrolyte inside the battery.
- Gel batteries
Gel batteries, like AGM batteries, are made to contain the electrolyte and keep it from evaporating or spilling. In this design, the sulfuric acid is suspended in a silica gel, which makes the battery very stable and has a low self-discharge rate over long periods of time.
The least amount of hydrogen gas is released from gel batteries’ vent valves, making them the safest lead acid batteries. They operate effectively in locations where high temperatures are a concern and can have their lifetimes discharged below 50% without deteriorating.
How Much Will a Lead Acid + Solar Setup Cost?
Everything depends on how many batteries you want. The short answer is that you’ll pay twice as much as with a hybrid solar system.
A good 3kW solar system currently costs $5,000 to install. This system will cost about $10,000 if you want to add 4kWh of usable storage. 4kWh of electricity storage will get an efficient house through the night.
Unfortunately, the typical Australian home is not very efficient, so you might need a larger system. You’ll currently pay about $8,000 for an installed 5kW solar system without batteries. If you add 8kWh of usable storage, the final cost would be closer to $18,000. An average homeowner could stay at home all night with this.
We have more comparisons of lead acid batteries:
- Differences Between the Alkaline Battery and Lead Acid Battery
- Lead Acid Battery Vs Lithium-ion
- Gel Battery Vs Lead Acid Battery: Which is Better?
- Are AGM Batteries Better Than Lead-acid?
- Can You Mix Lead-acid and Lithium Batteries?
Conclusion: Lead Acid Solar Battery
Lead acid batteries for solar energy storage are called “deep cycle batteries”. Although lead acid batteries are an established form of energy storage, they are relatively large and heavy for the amount of energy they can hold.
A DoD of 80% or higher will be found in almost all high-quality solar batteries on the market. A DoD of 90% is typical for lithium-ion batteries.
Here is more information about lead acid batteries:
- Can Lead-acid Batteries Be Recycled?
- Can Lead-acid Batteries Explode?
- How Do Lead-acid Batteries Work?
- How Do You Charge a Lead-acid Battery?
- How Long Do Lead-acid Batteries Last?
- How Long to Charge the Lead Acid Battery?
- How to Desulfate a Lead Acid Battery?
Can Lead Acid Batteries Be Used for Solar?
Flooded lead acid batteries (sometimes called “wet cell” lead acid batteries) are the most common type of deep-cycle solar battery. Although Lithium-ion solar batteries become more cost-effective over time, they have been in use for decades, are well understood, and are initially the least expensive solar storage battery.
Why Lead-acid Battery is Not Used in EVs?
However, low specific energy, poor cold-temperature performance, and short calendar and lifecycle impede their use. Advanced high-power lead-acid batteries are being developed, but they are only used for ancillary loads in commercially available electric-drive vehicles.