Bluetti EP900 Home Battery Backup Review: A Powerful Home Backup You Can Install Yourself

7.5

Bluetti EP900 Home Battery Backup

Like

• High power output
• Modular design
• Price transparency
• Great warranty
• Can be installed without solar panels

Don't like

• Lower efficiency
• Lower depth of discharge

Bluetti is no stranger to batteries. As a company mostly known for its portable power stations and solar generators, the logical next step is a whole home backup solution. This is where the EP900 Home Battery Backup comes in. 

The "EP900" is actually a powerful 9-kW inverter. This inverter sits on top of several small B500 batteries, able to store about 5 kWh each. The system itself almost looks like a battery tower, with a bunch of little gray boxes all stacked on top of each other. This is a refreshingly different aesthetic from the "garage refrigerator" look that's popular with home batteries. It also scored the highest in our ranking of the best solar batteries. 

"The most unique aspect of the EP900 is that it is an all-contained ESS [energy storage system] device," Brian Shircliffe, a sales director of home energy storage systems at Bluetti, told CNET. "We've put it all in one unit."

We did not conduct any hands-on testing for this review. Batteries are part of a complex home energy system that varies between households. Instead, this review is based on publicly available information online from Bluetii and an interview with Shircliffe. 

Here's what you should know about Bluetti EP900 Home Battery Backup. 

What do I get with the Bluetti EP900 Home Battery Backup?

The EP900 system offers a modular design with multiple capacity options and a powerful 9-kW inverter. You'll also get a 10-year warranty. This battery system's round-trip efficiency and depth of discharge is lower than other batteries on the market, but it's not terrible. We'll talk more about specs and warranty below. 

The EP900 is compatible with new and existing solar panel systems. Or you can install it without solar panels as a standalone backup power source. Here's a quick look at some of the specs for the Bluetti EP900.

System components 

The EP900 system's design is a bit more simplistic than other batteries we've looked at. Bluetti did this so that if you buy the battery you'll be able to install it on your own, Shircliffe said. If you're tech-savvy and confident with electrical instructions, you could take the DIY approach. The best part about this is that you'd save thousands of dollars on installation costs. However, if you'd rather leave these sorts of things to professionals, there's an option to hire an installer too. 

"This comes as a kit. Everything's been pre-crimped and cut," Shircliffe said. "When you order one of these, it gets drop-shipped to your house very similar to any of our other consumer products. And then it takes about 20 to 30 minutes to unbox it, maybe another 10 to 20 minutes to assemble it, plug in all the connections, hit go. And then you've got [an] up and running solar battery."

The actual components are standard. You've got the B500 battery modules, EP900 inverter and a sub panel. The B500 battery modules store energy and get placed on the system's base and stacked on top of each other, installed in parallel. The EP900 inverter is what converts DC electricity into AC electricity that your home can use. This gets installed on top of the battery modules, sitting as the head of the system. The entire setup should look like a tower.

There's also the sub panel, also referred to as the critical load panel. This small box acts as a sort of middleman between your home's main electrical panel and the battery system. The AC output is what gets wired to the critical load box, Shircliffe said. You'll also have two inputs wired in there. One for the battery and one for the grid. These circuits go onto this separate panel so that they can be controlled and maintained separately from other circuits.  

If you choose to install the EP900 system outside, you also have the option of installing a little enclosure that goes around it. This shelter has an almost shed-like appearance, so if you don't want people to walk by and see a battery tower, this is a good cover-up.

Capacity and modularity 

The EP900 has a modular battery design, meaning you'll be able to upgrade your capacity in smaller increments on the same system, versus having to buy another giant battery. This also allows you a bit more wiggle room when trying to find the battery capacity that's "just right" for your household's energy needs. 

"Everything we do is modular," Shircliffe said. "So let's say a year or two later, you decide, 'Hey, I think I do need another battery or more capacity.' You can add to it or you can even add another device as well. So you can have up to two of these devices installed at your house."

Capacity is determined by the amount of B500 batteries you choose to install with your system. Each B500 battery stores about 5 kWh. You can install two B500s for 9.9 kWh, three B500s for 14.9 kWh or four B500s for 19.8 kWh. If you find yourself needing more than 19.8 kWh, you can install another EP900 system for a total battery capacity of 39.6 kWh. Keep in mind that these numbers are the maximum capacity, not the usable amount. The chart below has a quick capacity breakdown.

Performance and efficiency 

The EP900 system has an impressively high power output. The higher your battery's power output, the more of your home you'll be able to backup during an outage. The EP900 has a continuous power output of 9 kW. Very few residential batteries on the market are this powerful. The cool part is that you'll get all this power at any capacity size you choose with the EP900 system. Normally, this kind of power is only reserved for much larger batteries, so if it's power you're after, this is definitely worth considering.  

Round-trip efficiency is an area where the EP900 system is weaker. Round-trip efficiency is essentially how much electricity makes it to your battery without getting lost during the storage process. The higher your round-trip efficiency, the less electricity you're wasting. Most home batteries nowadays have a round-trip efficiency rating of at least 90%. The EP900 has one of the lowest efficiency ratings we've seen, at 85%.

The battery's depth of discharge is a bit lower than the competition. Depth of discharge is how much energy you're able to drain from your battery's maximum capacity without causing damage to it. The lower the depth of discharge, the less of your battery's maximum capacity you'll be able to use. The actual batteries of the Bluetti EP900 system are the stacked B500 batteries, each with a 90% depth of discharge. We've found the average depth of discharge for these types of batteries to be about 95%, making the EP900's depth of discharge a bit lower than some of the other batteries out there.

Warranty

The EP900's warranty is actually pretty good, even though it might not appear that way on the surface level. A 10-year warranty is basic for these types of batteries and is considered the industry standard. But the expected energy throughput and end-of-warranty capacity guarantee are worth your attention. The rated energy throughput per B500 battery module is 15.48 MWh, which is pretty good for a little 5 kWh. Bluetti also offers one of the higher capacity guarantees we've seen, at 80%. Most manufacturers will usually only guarantee up to a 70% original capacity retention.

Years: This is the length of time your battery is covered under warranty. After 10 years, your warranty expires.

Energy throughput: This is the expected amount of total energy (in megawatt-hours) that will flow through your battery during its lifetime, determined by the manufacturer. Once your battery hits its rated throughput, your warranty expires, regardless of how many years you have left of your warranty.

End-of-warranty capacity guarantee: Your battery won't be able to retain its original capacity during its lifetime. An end-of-warranty capacity guarantee is the manufacturer's promise that your battery will still be able to retain up to a certain percentage of its original maximum capacity by the time your warranty ends. Bluetti guarantees that your battery system will be able to retain up to 80% of its original starting capacity by the end of your warranty.

Customer support

If you need support for your battery system, most manufacturers are going to point you toward your installer. But since the EP900 system ships directly to you, it's mostly a DIY install. There's not really a "designated installer" anywhere in the process. You'll likely have to hire an electrician to help you get the critical load panel installed. If something's wrong with your system, you could try to reach out to that same electrician, but there's no guarantee they'll be able to help. In this case, you're much better off reaching out to Bluetti directly. 

There are two ways you can contact Bluetti for support. You can call their support phone number or send them an email. If you think your issue is something that you can fix on your own, Bluetti also has a library of video resources and FAQs to help you troubleshoot.

How much does the Bluetti EP900 Home Battery Backup cost?

How much you'll pay for the EP900 system mostly depends on how much energy storage capacity you want. And since the EP900 system is shipped direct-to-consumer, there's a certain level of price transparency that other battery manufacturers don't have. You can easily go to Bluetti's website to see how much the battery setup you want is going to cost. 

We found the prices we saw to be pretty fair for what you get, but also a little more expensive than other batteries of similar size. If your budget is your top priority, there are cheaper batteries on the market. A general rule of thumb to follow with battery pricing is that you can typically expect to pay somewhere between $1,000 and $2,000 per kilowatt-hour of storage.

Here are the listed prices we found on Bluetti's website. Keep in mind that these prices are subject to change and don't include the cost of professional installation.

Is the Bluetti EP900 Home Battery Backup my best choice?

There's no definitive "best battery." Because everyone's house and energy needs are different, there isn't one battery that is going to be the best fit for every home. The best battery for you is the one that aligns with your energy needs and what you're planning to use it for. If a modular battery design, high power output and a good warranty are your top priorities, then the Bluetti EP900 might be a good match for you, especially if you feel confident enough to install the system yourself. This is one of the least efficient home battery systems that we've seen on the market. But that might not matter to you.

Don't limit yourself to just one battery, no matter how good it looks. The battery market is vast, and most installers can install more than one brand of battery. We recommend looking at a few batteries from installers in your area before making a final decision. Getting multiple quotes from installers might save you thousands of dollars too. 

How we evaluated the best solar batteries 

First let's be clear: Not every solar battery is right for every home. Solar is a very site-specific and personalized decision process, so it's a little tricky to pinpoint exactly which solar battery is the "best" battery for your home's energy needs without doing an on-site consultation. 

It should also be said that we didn't have any form of hands-on testing with any of the batteries we scored. This methodology also assumes you're purchasing a battery for the main purpose of using it for energy backup. If you mainly plan to use your battery for energy offset or to take part in a virtual power plant, there are likely better options than what we have featured in our reviews and rankings. We strongly encourage you to do your own research, as well as to speak with installers in your area. An installer will be able to get a better understanding of your home's energy use and what sort of system you might need. 

We used a few ways to evaluate and compare these batteries to find the stand-outs. Here's how we developed our list of top solar batteries.

First, we determined which categories would be used to evaluate each battery's performance, capacity and value. We also weighted each category. The weight of each category reflects the importance we felt was relevant to the average consumer: 

• Modularity: 20%
• Warranty: 20%
  
• Round-trip efficiency: 15%
  
• Power output: 15%
  
• Depth of discharge: 10%
  
• Price: 5%
  
• Price transparency: 5% 
  
• Customer support options: 10%
  

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

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