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When purchasing solar batteries for your home solar power system, there are numerous aspects to consider. The kind of battery you desire and the specific results you hope to get from it are two items to consider.
Lead-acid, lithium-ion, nickel cadmium, and flow batteries are the four varieties of solar batteries. Lithium-ion batteries are the most widely used home solar batteries. There are two types of lithium-ion batteries: AC and DC linked. While DC-coupled batteries are best suited for simultaneous installation with solar panels, AC-coupled batteries can be connected to pre-existing solar panel systems.
To assist you in selecting the best battery backup for your solar panel system, we have dissected the most widely used energy storage systems.
Types of solar batteries
There are four main types of battery technologies that pair with residential solar systems:
Lead acid batteries
Lithium ion batteries
Nickel based batteries
Flow batteries
Because of its distinct qualities, each of these battery backup power options works best with a particular kind of solar system. Let’s examine the benefits of each kind of solar battery in more detail.
Lead acid batteries
In the realm of solar batteries, lead acid batteries are the tried-and-true technology.
Since the 1800s, in fact, these deep-cycle batteries have been employed to store energy. Additionally, their dependability has allowed them to remain.
Flooded and sealed lead acid batteries are the two primary varieties of lead acid batteries.
Popular lead acid batteries that homeowners can purchase include:
- Trojan J185E-AC Deep Cycle Flooded Lead Acid Battery
- Crown Battery’s Crown1 absorbent glass mat (AGM) Sealed Lead Acid Battery
- Deka Solar’s 8g30H Gel sealed lead acid battery
Best for: The reliability of lead-acid batteries is great for off-grid solar systems, or for emergency backup storage in case of a power outage.
| Feature | Pros | Cons |
|---|---|---|
| Cost | ✅ Cheap | ❌ Short lifespan |
| Reliability | ✅ Reliable | ❌ Require regular maintenance |
| Eco-Friendliness | ✅ Easy recycling and disposal | ❌ Installation limitations |
Lithium-ion batteries
The newest addition to the energy storage market is lithium-ion batteries.
Manufacturers of electric vehicles became aware of lithium ion’s potential as an energy storage technology as EVs gained popularity. They soon rose to prominence as one of the most popular banks of solar batteries.
For residential setups, the most often used lithium-ion solar batteries are:
Tesla’s Powerwall battery
Enphase’s IQ batteries
One of the biggest disadvantages of lithium-ion batteries is that they are more expensive than other energy storage technologies. The Tesla Powerwall costs about $16,000 and is one of the cheapest options available!
Best for: Lithium-ion batteries are best for residential solar installations because they can hold more power in a limited space and allow you to use more of the energy stored within the battery, which is great for powering a home.
| Feature | Pros | Cons |
|---|---|---|
| Maintenance | ✅ Require little maintenance | ❌ High upfront costs |
| Energy Density | ✅ High energy density | ❌ Increased chance of thermal runaway if installed poorly |
| Lifespan | ✅ Longer lifespan |
Nickel cadmium batteries
Lithium ion or lead acid batteries are more commonly utilized than nickel cadmium (Ni-Cd) batteries.
The late 1800s saw the introduction of Ni-Cd batteries, but in the 1980s, they underwent a transformation that significantly expanded their energy storage capacity. They are well-liked in the aviation sector.
Some of the leading producers of Ni-Cd batteries are Enersys and Saft.
Best for: Due to its longevity, Ni-Cd batteries are widely used in large-scale applications, such as utility solar energy storage.
Pros
Feature Pros Cons Durability ✅ Durable ❌ Prone to memory effect, limiting charge capacity Temperature Resistance ✅ Operate at extreme temperatures Maintenance ✅ Require little maintenance Battery Management System (BMS) ✅ No complex BMS needed ❌ Cadmium is extremely toxic
Flow batteries
In the field of energy storage, flow batteries are a new technology.
They have a water-based electrolyte liquid inside the battery that circulates between two different chambers, or tanks. Chemical reactions that take place when charged enable the energy to be stored and then released. The popularity of these batteries is now starting to grow.
They cost more than the other battery types because of their larger size. They are difficult to modify for domestic usage due to their size and high cost. Redflow, on the other hand, produces a flow battery for homes that they name ZCell.
Best for: Large-scale installations are the ideal application for flow batteries.
| Feature | Pros | Cons |
|---|---|---|
| Depth of Discharge | ✅ 100% depth of discharge | ❌ Low charge and discharge rates |
| Lifespan | ✅ 30-year lifespan | ❌ Very expensive |
| Safety | ✅ Minimal fire risk | ❌ Low storage capacity |
| Space Requirement | ❌ Require a lot of space |
DC-coupled vs AC-coupled solar batteries
Although alternating current, or AC power, is the kind of electricity utilized in homes and buildings, direct current, or DC power, is required to charge batteries. Additionally, solar panels generate DC power.
To use the energy stored in batteries in your home, an inverter must first transform the DC electricity into AC power. Energy is lost each time electricity is switched from DC to AC (or the other way around).
The location of the inverter in the system determines whether a battery is DC-coupled or AC-coupled. While an AC-coupled battery has its own connection, a DC-coupled battery connects directly to a hybrid string inverter, allowing the DC solar power to go straight to the batteries.
DC-coupled battery advantages and disadvantages
The energy stored in a DC-coupled battery is more efficient since it can be charged directly from solar panels and only needs to be converted to AC once. Because a battery-specific inverter is not required, this configuration also makes it possible for a DC-coupled battery to be installed alongside a new solar system at a lower cost.
Unfortunately, this also means that unless the solar panels are already linked to a battery-ready hybrid string inverter, a DC-coupled battery is not the best option for a home with solar panels.
The benefits and drawbacks of AC-coupled batteries
Because they have their own inverter and can be charged using the house’s standard AC circuits as well as from solar electricity that has previously been converted using any type of existing inverter or microinverter, AC-coupled batteries are easy to install in any household.
Unfortunately, because the power must be converted twice or three times from DC to AC and back again, an AC-coupled battery is likewise less efficient. For every conversion, efficiency declines by about 1% to 2%.
How can we choose the best kind of solar battery to use
Lithium batteries are typically the best option for a home solar installation.
They have high efficiency, can discharge the majority of their stored energy, and can store more energy in a smaller amount of space. Additionally, a lot of solar firms will be able to install a lithium ion solar battery precisely and safely because these are the most prevalent.
Lead acid batteries can be your best bet if you’re on a tight budget. They are inexpensive and have been in use for many years.
Lithium ion and lead acid are the most popular solar batteries for a reason, even if you could also acquire a Ni-Cd or flow battery to go with your solar system. You should contact nearby solar installers to determine which kind of solar battery will best suit your requirements.
