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Best Battery Backup Systems

With solar becoming a more popular option for homeowners, companies are eager to enhance the technology in the solar industry. Many battery backup systems are on the market, but which ones are worth purchasing?

Why Do I Need a Battery Backup System?

Battery backup systems go hand-in-hand with the evolving technology in the solar industry. If you live in a rural area, an area prone to power outages, or are frustrated with time of use policies implemented by power companies, a battery backup system is something to consider investing in. Essentially, it is a generator that pays for itself over time.

What Is the Purpose of a Battery Backup System?

Battery backup systems can serve a homeowner or business owner in a number of ways. The main appeal of these batteries is that they allow for homeowners to not be reliant on the grid. They can store energy you aren’t using throughout the day and then power your home at night. During a power outage, it only takes milliseconds for power to switch from the grid to the battery backup system.

The typical system a homeowner would purchase is best for powering lights and small appliances; HVAC systems and a stove are examples of what would not be cost efficient to power with one of these backup systems. You do not need a solar system to purchase a battery backup system, but if you are interested in receiving the federal tax credit, you do need solar.

Which Battery Backup Companies Are the Most Reliable?

The companies discussed today are sonnen, Enphase, and Fortress. These are some of the most popular and reliable companies offering battery backup systems. They all stay on top of technology at the forefront of this industry while trying to remain as environmentally friendly as possible.


sonnen prides itself on the design and technology of its systems. sonnen has three different models: sonnenCore, eco, and ecoLinx. All of these models have lithium iron phosphate battery chemistry, often referred to as LFP batteries. According to sonnen, they use these batteries due to their “stability, durability, performance, and environmental friendliness.”1 Because they use LFP batteries, this means that all of their batteries are 100% recyclable at an R2 facility.

sonnenCore batteries have a maximum energy capacity of 10kWh and have a cycle warranty of 10 years or 10,000 cycles.

The eco batteries have a maximum energy capacity of 20kWh and a warranty of 10 years or 10,000 cycles.

The ecoLinx batteries have a maximum energy capacity of 30kWh and a warranty of 10 years or 10,000 cycles.


Enphase also uses lithium iron phosphate batteries, but it only has two models: the Encharge 3 and Encharge 10. Enphase touts its all-in-one AC coupled storage system for the battery backup systems. They also place a heavy emphasis on the microinverter technology in the systems.

The Encharge 3 has an energy capacity of 3.36kWh and 4 embedded microinverters with a 1.28kW power rating.2 The Encharge 3 has a 10 year warranty as well.

The Encharge 10 combines three of the Encharge 3s into one system. It has a 10.08 kWh energy capacity and 12 microinverters with a 3.84kW rating. The Encharge 10 also has a 10 year warranty included with it.


Fortress has a number of products that can be beneficial for someone trying to reduce their reliance on the grid, but we are going to be discussing the eFlex 5.4 Solar Storage Battery, eVault 18.5kWh LFP Battery, and the eVault Max 18.5kWh LFP Battery.3

The eFlex 5.4kWh is designed to be compatible with most converters and is an LFP battery. It comes with a 10 year warranty or about 6,000 cycles.

Fortress’s eVault 18.5kWh LFP Battery offers more energy than the eFlex, and it comes with the same warranty. It is more ideal for providing backup power to residential and commercial buildings. Up to 12 batteries can be connected to allow for a maximum energy capacity of 222kWh. Each battery has an easy to read LCD screen with all the essential numbers on it.

The eVault Max 18.5kWh LFP Battery is the newest battery in Fortress’s quality products. They took the eVault 18.5kWh and made some slight enhancements. The batteries have an LED screen on the outside and up to 20 units can be connected. This means that the maximum energy capacity is 370kWh. For the average homeowner, this would be incredibly expensive, but it could be a good match for a commercial building. The warranty for one of these is also 10 years or 6,000 cycles.

In Summary…

Battery backup systems are a great option for people wanting to be independent from the grid. Solar panels do not require a battery backup system, but they do provide on-site energy storage. These batteries pay for themselves over time, and if they are assisting a solar system, you are eligible for a federal tax credit.

The companies sonnen, Enphase, and Fortress all offer high-performing battery backup systems. They continue to develop new technology and put out competitive products that aim to meet the needs of consumers.

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