FranklinWH battery review: A powerhouse battery with a price tag to match

Home batteries are getting bigger, more powerful, and smarter. But while many batteries do one or two things really well, the FranklinWH aPower 2 stands out for its performance across the board.

FranklinWH has quickly become a popular name in home energy storage and one of the best batteries on EnergySage. The aPower2 works with almost any existing solar setup, offers strong whole-home backup potential, and intelligently optimizes home energy sources (e.g., solar panels, stored energy, or the grid) to maximize daily savings.  

That said, it’s not the perfect fit for everyone. The upfront cost is higher than some competing batteries, and because each unit stores a lot of energy, it’s not as flexible for homeowners who want to add storage in smaller increments.

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The FranklinWH aPower pairs with the company’s aGate smart energy controller, which manages power flow between your solar panels, battery, home, and grid, and automatically switches to backup power at the first sign of an outage.

FranklinWH aPower 2 specs

The most important specs for any home battery are usable capacity (how much energy it can store, measured in kWh) and continuous power output (how much it can deliver at once, measured in kW).

You can think of it like water flowing through a pipe. The capacity is the total amount of water available, while power is the width of the pipe—or how much can flow at once. A wider pipe (higher power) lets you run more appliances simultaneously, but it depletes your supply faster. A larger reservoir (higher capacity) lets you run appliances for longer, even if the pipe is narrower.

The aPower 2 has 15 kWh of capacity, above average for a single residential unit (most competitors offer 10 to 13.5 kWh of capacity), and its 10 kW continuous output is well above the 5 to 7 kW range typical of most home batteries on the market. That combination means a single aPower2 unit can power more of your appliances during an outage compared to the average home battery.

You’re on a time-of-use (TOU) electricity rate plan

If your utility charges different electricity rates depending on the time of day—higher in the evenings and lower overnight or midday—a home battery can help you avoid buying expensive power from the grid when rates spike.

What makes the aPower 2 stand out is the intelligence built into FranklinWH’s aGate controller. Instead of manually setting charging and discharging schedules, the system automatically monitors electricity pricing and decides when to pull from solar, battery storage, or the grid to help lower your energy costs.

During expensive peak-rate hours, it prioritizes stored battery power and solar energy to reduce grid usage. And with 15 kWh of usable capacity, the aPower 2 has enough storage to cover most households through the evening hours, which are typically the most expensive part of a time-of-use rate plan.

You’re adding storage to an existing solar panel system

If your solar panel system is already up and running, you can typically add the aPower 2 without replacing your current inverter or making major changes to the system architecture. Because it’s AC-coupled, it doesn’t need to be directly integrated into your solar inverter system the way DC-coupled batteries do, making it a great option for retrofit installations. 

It can power major appliances during an outage

With 10 kW of continuous output and up to 15 kW of short-term surge power, the aPower 2 can run heavy household loads like air conditioning alongside essential circuits during an outage—something most single residential batteries struggle to do. For homeowners who want whole-home backup rather than just keeping the basics on, that extra headroom makes a real difference.

The warranty is genuinely best-in-class

The aPower 2 has one of the strongest warranties in the home battery space. At 15 years, it’s well above the industry standard, and FranklinWH backs it with a 60 MWh throughput limit, so everyday cycling doesn’t burn through coverage.

For something you’re going to depend on for years of backup and savings, that extra buffer matters.

You’re on a tighter budget

The FranklinWH aPower2 isn’t the most expensive battery on the market, but it’s certainly not the cheapest, either. At $1,177 per kWh, you’re looking at a $17,655 installation for a single-battery system—that’s not chump change. 

If your goal is simply keeping the lights on during outages, a smaller, lower-cost battery can absolutely get the job done. Systems like the Tesla Powerwall 3, which averages around $13,473 installed, are often a more budget-friendly entry point for single-battery setups.

That said, the aPower 2 starts to make more financial sense at scale. Whole-home battery backup typically requires around 30 kWh of storage, which the aPower delivers with just two batteries for roughly $35,300. At that same threshold, you’d need three Powerwall 3 units to reach capacity, which pushes the total to about $40,400. So, even though the aPower 2 has a higher sticker price per kWh, it may be the more affordable option for larger, whole-home systems.

You want the most efficient battery on the market 

Because the aPower 2 is AC-coupled, energy from your solar panels goes through an extra conversion step before being stored—from DC to AC and then back to DC—which results in some energy loss along the way. DC-coupled batteries, like the Tesla Powerwall 3, skip one of those conversion steps, making them slightly more efficient overall. The difference is modest in practice, but if maximizing the amount of solar energy you actually store is a priority, it's worth considering.

You want flexibility to add capacity in the future

Scaling up the aPower 2 means adding another full 15 kWh unit each time you expand. That works well if you’re planning a larger, long-term system, but it’s less flexible if you just want to bump up storage a little at a time.

Some competing systems offer more modular expansion, letting you add smaller increments of capacity as your needs grow. That can make it easier to start small and scale gradually without committing to a full additional battery upfront.

For homeowners with uncertain or evolving energy needs, that difference in scalability can be an important factor when choosing a system.

The FranklinWH aPower 2 stands out for its combination of power, intelligence, and a long 15-year warranty. With 15 kWh of usable capacity and 10 kW of continuous output per unit, it’s one of the strongest battery options for homeowners who want more than basic backup power.

It’s especially compelling for homeowners with existing solar systems who want a straightforward storage upgrade, or for larger whole-home backup setups where multiple units make sense.

That said, it’s not the cheapest option, and it’s less flexible if you only want a small amount of storage or prefer gradual expansion. Like all home batteries, the right choice comes down to your energy needs, your solar setup, and how much backup power you actually want when the grid goes down.