Bluetti AC300 & B300 home battery backup review: incredible expansion for any situation

The Bluetti AC300 & B300 home backup battery combo can be the first step in developing an expandable off-grid power solution.

We've reviewed a lot of power stations, but this is the first time we've encountered a separate inverter and battery station combo. Those seeking to purchase this Bluetti system needs to know this before anything else -- the AC300 and B300 are a required combo.

These kinds of batteries go by several names, like solar power generator, portable power station, and home battery backup. They tend to refer to similar components, just arranged with varying accessories like additional expansion batteries or solar panels.

Bluetti pitches the AC300 & B300 combo as a portable power station despite their massive 127 pound weight when stacked. While it's possible to separate the units for moving them, we're not sure the average user is buying this system for travel needs or camping.

The primary selling point of the Bluetti AC300 & B300 is the expandability of the system and the power/efficiency of the inverter. While we reviewed this single set, users can add another AC300 and seven more B300 units for an incredible 24,576 Wh of power storage.

That isn't a system you're going to pack into the back of your truck for a camping trip. If that's your goal, there are dozens of better options, some from Bluetti themselves like the AC200Max or the much more portable AC180.

This is a home battery backup system, and that use case is the focus of our review.

Bluetti AC300 & B300 home battery backup review -- design

As we stated at the top, these products aren't independent systems that can be joined for more power. Instead, the AC300 is a big inverter that doesn't have any internal battery itself while the B300 is a 3,072 Wh battery pack.

The AC300 looks incredibly similar to Bluetti's AC200Max, so it's easy to confuse with a battery. However, once you pick it up, it's clear that it's too light to house a battery at 47.6 pounds.

Its dimensions are 20.5 inches long by 12.5 inches wide by 14.1 inches tall. The AC300 may not have a battery, but it has the main control screen and almost all of the outlets.

There are six 120V/20A grounded outlets, one 120V/30A TT-30 outlet, one 100W USB-C port, two 18W USB-A ports, two 5V/3A USB-A ports, a 12V/30A DC RV outlet, and a 24V/10A car outlet. In addition to these 14 outputs, there are two 15W wireless charging pads.

For inputs, there is an AC charging cable rated for 3,000W max, a solar input rated for 2,400W max, and a 12/24V cigarette lighter port. The solar and AC ports can be used in tandem for 5,400W max input, but only with two B300s connected.

If two AC300s are connected together, they can be used for 240V split phase bonding.

The B300 is much smaller, but also more dense. It weighs 79.6 pounds and is shorter at 10.5 inches tall.

There is a 100W USB-C port, an 18W USB-C port, and a 12V/10A car outlet. The B300 lacks AC outlets since it doesn't have an inverter -- that's the AC300s job.

Charging the B300 is possible without the AC300 connected, but it is much slower. There is a 500W max AC input, a 200W max solar input, and a 12/24V cigarette lighter port. Combine AC and solar for 700W max input.

Since the devices are meant to stack, the length and width of both the AC300 and B300 are identical. When stacked in any order, they click into place.

The B300 can be charged independently from the AC300, but it lacks port options to be used for output alone.

Bluetti AC300 & B300 home battery backup review -- features

Primarily, this is a battery system. With one B300 connected it has a 3,072Wh capacity.

One B300 can run a refrigerator for a day and a half or a space heater for close to two hours. An easier comparison might be a smartphone, which could be recharged about 115 times at this capacity.

The AC300 packs a few features in that aren't apparent at first glance. It can act as an uninterruptible power supply with custom parameters, plus the DC input source supports parallel connections.

The DC input on the AC300 connects over a dual DC cable connection. With this cable, the user can charge their system via solar panels, a car charger, generator, or combination of any two.

Customers interested in charging the Bluetti AC300 from a 3,000W source will need to purchase a separate 30A charging cable. Otherwise it charges at 1,800W AC.

Use the Fusion Box Pro to connect two AC300 in parallel, which means up to eight B300 can be used at once for 24,576Wh of stored energy -- also sold separately.

Uninterrupted power supply settings

Since AC300 can operate as a UPS with various modes. There are standard, time control, PV priority, and custom modes.

Standard passes power to the connected load from the grid while keeping the battery at 100%. Time control allows users to set when the battery charges so it can use cheaper grid power, and set when it discharges to the load instead of the grid.

PV priority mode prevents the battery from charging via the grid except for 30% of its capacity. The remaining charge will be provided by solar.

The custom mode enables users to combine the various modes to suit their needs.

Considering use cases

Since there isn't an internal battery, the AC300 won't power on without being attached to the B300. If you have multiple B300 units, one can be hot-swapped without powering down the whole system so long as one other B300 is always attached to the AC300.

This can be useful if the main system is located somewhere like a basement and solar cables won't reach, or an alternative power source like an outdoor generator is available. Simply remove a depleted B300, take it to where it can be charged, and return it to continue powering the system.

These types of use cases are what the AC300 & B300 combo make sense for a home battery backup solution. Modularity is key, and luckily the B300 battery can charge via AC or solar independent from the AC300.

Using the Bluetti AC300 & B300 home battery backup system

In order for the Bluetti AC300 & B300 combo to act as a whole home backup solution, owners will need to install the Smart Home Panel. Otherwise, the system functions more like a portable power station and the various outputs come into play.

We don't have a Smart Home Panel, so our use case would involve carrying the AC300 & B300 to wherever power was needed. For example, if there was a power outage, it would be set up in the kitchen to keep the refrigerator running.

Despite its weight and obvious use case for home backup, it can still take the place of a portable power station. Since it is a modular solution, homeowners can buy this system and numerous expansion batteries, but take only what is needed on the go.

As we said, there are better portable solutions out there if portable power is the goal. However, the AC300 & B300 combo operates somewhat as the best of both worlds, and Bluetti does sell a $300 cart for transporting this heavy equipment.

Charging the B300 battery through the AC300 is fast and simple. Connecting it with the included AC cable nets 1,800W of input, which can fully charge one B300 in under 2 hours.

Connecting solar panels to charge depends on several factors, like the panel's rating, number of panels in use, and the weather. Solar input can peak at 2,400W with two B300s connected.

Connect a 200W solar panel and an AC outlet at the same time to get 2,000W of input. As we stated earlier, there are many input combinations that are supported.

Like other power stations, outputs need to be toggled on to be used. The AC and DC outputs on the AC300 are toggled from the app or the touchscreen display.

We're not sure why Bluetti put the 15W wireless pads in the AC300. Bluetti seems determined to convince people this is a portable power station equivalent, when we're not sure that's the case.

The B300s few outputs are toggled from a button above the USB-C ports.

Bluetti put a clear warning above the 24V DC car charger port, but we'll reiterate it here. It is not compatible with 12V equipment and could damage it.

The Bluetti app

The Bluetti app is easy to operate once past the main screen. As we've stated in other Bluetti reviews, it seems odd that there's a forum built into the app.

Go to the devices section to access connected Bluetti devices and have easy access to multiple features. The touchscreen panel on the AC300 is better than most power station control options, but not amazing in direct sunlight.

We appreciate having access to general functions and the UPS programming option within the app. Everything is easily discovered and operated.

Modular home battery backup

The AC300 and B300 combo isn't for everyone. We believe it is a system best suited for people taking their first steps into grid independence.

While the unit is technically portable, we can't recommend purchasing it for that function. This system is best used as a power backup solution that sits in one place for long periods of time.

The more expensive systems with more capacity can be too far out of reach for most customers. Getting to an incredible 24kWh system one B300 at a time is much easier to achieve.

We prefer the all-in-one battery units that have optional expansion packs, like the Jackery 2000 Plus system. It acts as a more versatile portable system with integrated wheels and optional expansion.

That isn't to say the Bluetti AC300 and B300 aren't worth investing in. Just keep in mind your use case when investing in such a heavy duty, expensive system.

Bluetti AC300 & B300 home battery backup - Pros

• Incredible expansion opportunity
• Fast charging speeds without a large external power supply
• Operates quietly under heavy load
• Plenty of outlets, plus the RV output will be useful for campers

Bluetti AC300 & B300 home battery backup - Cons

• Not a portable system despite Bluetti's best efforts to convince customers otherwise
• 15W wireless pads on a system built for stacking and expansion seems like an odd choice
• 24V car charger output seems like a broken 12V device waiting to happen

Rating: 4 out of 5

The Bluetti AC300 & B300 system is difficult to rate. For those seeking out a modular system with plans for future expansion, this combo pack is easily a 4.5 out of 5 or better.

However, we're writing this review with a wider audience in mind. There are better options that function specifically as a home battery backup solution or a portable power station.

If you're looking for a portable power station, this is a 3 out of 5. It functions for that use case, but really, look at the other options.

Where to buy the Bluetti AC300 & B300 home battery backup system

The Bluetti AC300 & B300 combo is regularly $3,299 on the Bluetti website, but is on sale for $2,599 at the time of publication. It is also available on Amazon for $2,599.