Having a battery that actually works is one thing. Making sure your installer is able to hook everything up correctly the first time is another. The easier the installation, the less likely you are to have problems. 

Tigo Energy is a company that creates solar hardware and software products for residential, commercial and industrial solar solutions. The company mainly works with installers and distributors, with the philosophy of creating solar products that are easy to install and manage. One of the company's main focuses is intelligent solar product management software.

"The software is the key," James Dillon, chief marketing officer of Tigo Energy, told CNET. "The batteries aren't super differentiated, hardware-wise. A box is a box. The key is making it easy to install for the installer. We differentiate with the installer, and that's where we focus."

We did not conduct any hands-on testing for this review. Batteries are part of a complex home energy system that varies between households. This review is based on publicly available information online from Tigo Energy and an interview with Dillon, conducted at RE Plus 2023, a renewable energy trade show in Las Vegas. 

Here's everything you need to know about the Tigo EI Battery. 

What do I get with the Tigo EI Battery?

The Tigo EI Battery is a 9 kWh battery, boasting higher efficiency than other batteries and the capabilities for AC- and DC-coupling, making it an ideal choice for new and existing solar panel systems. You'll also get an 11-year warranty on the battery. But the battery isn't the only thing Tigo Energy has to offer. With your battery, you'll also get Tigo's residential solar inverter, automatic transfer switch and solar optimizers.

Tigo's EI Battery is only compatible with solar, meaning you can't install it as a standalone backup power source. You'll either buy solar panels or already have a solar panel system installed on your property. Here's a look at some of the Tigo EI Battery's specs.

Tigo EI Battery specs CategoryDescription Usable capacity 9 kWhHow many can I install? Up to four battery enclosures (usable 36 kWh)Round-trip efficiency 94.40%Depth of discharge 90%Peak power output 6 kWContinuous power output 5 kWBattery chemistry Lithium iron phosphateAC- or DC-coupled? Options for bothPrice $6,500 - $9,000 System components

With a Tigo system, you'll have three boxes on the wall: the battery, inverter and the ATS. Tigo also offers power optimizers that plug into each of your solar panels up on the roof. Tigo's system setup isn't as compact and "out of the way" as other solar storage systems we've reviewed, but it still gets the job done. 

And it's not like there's an obnoxious amount of boxes on the wall. Here's a quick breakdown of each Tigo solar storage system component.

Tigo EI system components ComponentDescription Tigo EI Battery The battery is your energy storage component. Any energy generated by your solar panels that doesn't go immediately to power your house can be sent to the battery for storage.Tigo EI Inverter Tigo's inverter is a hybrid inverter, connecting your solar array and the battery to one main inverter So you won't need another inverter for your battery. The main job of the inverter is to convert the DC electricity that your solar panels make into AC electricity that your home can use.EI ATS Also known as the automatic transfer switch, the EI ATS connects to the inverter, essential load panel and has a grid connection. When the ATS detects a grid power failure, it automatically switches your system into backup mode, ensuring you still have power in the event of an outage. The ATS is capable of supporting a generator as well.Tigo TS4 Flex MLPE These are power optimizers that connect to each individual solar panel on your roof. Power optimizers offer module-level control, allowing you to monitor your solar panels individually and provides rapid shutdown if something goes wrong. Capacity and modularity

The Tigo EI Battery isn't one giant battery. It's actually a box enclosure containing three small 3.3 kWh battery modules. Each battery module has a 90% depth of discharge, so the usable amount of capacity boils down to about 3 kWh of usable capacity per module. 

One Tigo EI Battery enclosure has a usable capacity of 9 kWh. Up to four battery enclosures can be installed for a total usable capacity of 36 kWh.

Another thing we look for in home batteries is how modular they are. A modular battery is made up of several smaller battery modules installed in a single enclosure, versus just one giant battery. Household energy needs change over time. To account for this, some manufacturers design a modular battery with multiple capacity options, allowing you to find a capacity that's "just right" for your current energy needs, while also allowing you the flexibility to add capacity upgrades to a single battery unit. 

This is typically a cheaper alternative than going out and buying another giant battery. And since smaller battery modules weigh significantly less than one large lithium-ion battery, modular battery designs help make it easier for installers to perform the installation. 

"[Batteries] are not easy to install, and a lot of installers don't like to," Dillon said. "They'd rather install solar, which is easier and more straightforward. Battery is different. They don't want to come back out to the site. So an easy, quick install is hugely important."

However, Tigo doesn't offer any modular sizing options, so we had to dock some points. But if modularity isn't a priority to you, then just make sure a 9 kWh battery (or a multiple of it) is really what you need.

Usable capacity breakdown One battery enclosure Two battery encoluresThree battery encoluresFour battery encolures9 kWh 18 kWh27 kWh36 kWh Performance & efficiency 

The Tigo EI Battery's specs are pretty solid. But its power output is weaker than other batteries on the market. 

We'll start with round-trip efficiency. This is essentially a percentage measurement of the amount of energy that makes it from your solar panels, to battery storage and to your house without getting lost during the transition process. Most home batteries have a round-trip efficiency of around 90%. Tigo's battery does pretty well in the efficiency category, with a round-trip efficiency of 94.4%. 

Home batteries have two different capacity ratings: its usable capacity and its maximum capacity. Depth of discharge is essentially how much energy storage capacity you can use, relative to what its maximum capacity actually is. The higher the depth of discharge, the more of your battery's capacity you can access. From what we've seen, the industry standard depth of discharge for lithium-ion-based batteries is roughly around 95%. The Tigo EI Battery's depth of discharge is 90%. It falls a bit short, but it's not horrible. 

Lastly, there's power output. Most home batteries will have two ratings on how much power they can handle: peak and continuous. Peak power is the amount of power demand your battery can handle all at once without damaging anything. Batteries are usually only able to peak for a very short amount of time, generally less than a minute or two. This is helpful for starting power-hungry appliances. Continuous power is the amount of power the battery can handle continuously at any given moment.

A lot of the newer residential batteries we've seen on the market are getting pretty powerful, with continuous power output ratings reaching as high as 9 kW, or in rare cases, even 12 kW or more. The Tigo EI Battery's power ratings aren't necessarily bad. It's just a product of its time. A few years ago, 5 to 6 kW of power was pretty standard, but the market has changed a bit. Battery and inverter technology has tremendously improved within the past couple years, allowing newer batteries to have much higher power ratings. If power isn't really something you're concerned about, Tigo's battery is fine.

Performance & efficiency details Round-trip efficiency Depth of dischargeContinuous power outputPeak power output94.40% 90%5 kW6 kW Warranty

Tigo's battery is covered under warranty for 11 years or 6,000 cycles, whichever comes first. Most batteries on the market are only warranted for 10 years, making Tigo somewhat of a step up from the competition. But the 6,000-cycle count coverage is pretty standard in the battery world. And the end-of-warranty capacity guarantee from Tigo (65%) falls short of the industry standard of 70%. 

The Tigo ATS is also warranted for 11 years, while the Tigo EI Inverter is covered under warranty for a little over 12.5 years.

Warranty details Years covered Cycles coveredEnd-of-warranty capacity guarantee11 years 6,00065%

Years covered: This is the amount of time your battery is covered under warranty. 

Cycles covered: Most batteries come with a cycle or throughput clause. This is a measure of how much you're allowed to use your battery while still being under warranty protection. Every time you drain and recharge your battery, it completes a cycle. Once your battery hits a certain cycle count, your warranty expires, even if you still have some years of coverage left. 

End-of-warranty capacity guarantee: Batteries have trouble retaining their original capacity over time. An end-of-warranty capacity guarantee is the manufacturer's promise that your battery will be able to retain up to a certain percentage of its original capacity by the time your warranty period ends. 

Tigo Energy Intelligence app

Of course, your battery system comes with an app. It would be a red flag if it didn't. The Tigo Energy Intelligence app lets you monitor your battery's state of charge and configure your system's operating mode.

"It's designed for three different applications," Dillon said. "It's designed to have a battery that just handles backup, partial backup, full backup or a battery that just self-consumes [without having] to ship back to the grid. So it's got three different configurations."

Backup modes make sure that you have energy in reserve for when the power goes out, while self-consumption and time of use modes are helpful for offsetting expensive time of use rates, helping you save money on electricity by using energy from your battery during times of the day when electricity costs are at their highest. 

You'll also be able to monitor your home's energy production and consumption data, track the difference in performance between specific panels and have access to your home's historical energy data.

How much does the Tigo EI Battery cost?

The Tigo EI Battery will likely cost you somewhere between $6,500 and $9,000, according to listings from third-party retailers. You'll also have to buy the inverter and other equipment too, which will likely cost over $1,500. And don't forget installation. The cost of installation varies by installer, but you can usually expect to pay around $1,500 to $3,000. 

We found the average price range for the Tigo EI Battery to be fair. In the battery world, you can typically expect to pay between $1,000 and $2,000 per kilowatt-hour of storage. But we also recommend gathering multiple quotes from installers in your area to see who's willing to offer the best price. Taking the time to shop around a bit could save you thousands of dollars in the long run.

Is the Tigo EI Battery my best choice?

Because every household's energy needs and goals vary from house to house, we can't really call any battery "the best battery." The battery that you want is one that meets your energy needs and can perform what you want it to do. The Tigo EI Battery has AC- and DC-coupling capabilities, so there's a lot of flexibility with how you can have this battery hooked up. It's also got a higher efficiency rating than some other batteries out there, and it comes at a fair price for the amount of storage you get. You'll get an 11-year warranty, too.

But it doesn't have any modular capacity options to choose from on a single battery enclosure. So if you need a capacity upgrade in the future, you'll have to spend thousands more dollars on another 9 kWh battery, and you'll have another box on the wall. This battery's power output is lower than other batteries on the market as well, so if you're looking for a powerful battery, you'll have better luck with other options.

You shouldn't limit yourself to one brand of battery either. There are far more batteries on the market now than there were a few years ago. Take some time to shop around and see what types of batteries your local installers are carrying. Getting at least three quotes from a few installers in your area might help you save some big bucks, too.

How we evaluated the best solar batteries 

Not every battery is right for every home. It's difficult to pinpoint exactly which solar battery is the "best" battery for your home without doing an on-site inspection. We're unable to do hands-on testing with solar batteries because of the complexity of solar panel systems, but there are ways to evaluate and compare these batteries. Here's how we evaluate solar batteries.

First, we created categories that would be used to evaluate the battery's efficiency, performance, capacity and value. We also weighted each category. The weight of each category reflects the importance we felt was relevant to the average person. Here are the categories we considered and their weights:

Battery modularity (stackability): 20%Warranty: 20%Round-trip efficiency: 15%Depth of discharge: 10%Power output: 10%Price: 10%Customer reviews: 10%Battery capacity: 5%

We looked at more than 15 of the most common batteries on the market and collected the data for each category to compare the numbers. Each category (for every battery) was then given a tier-style rating (from 1 to 5) to see which aspects of each battery were above average (among those on our list), average or below average. 

Frequently asked questions