The home battery market has changed rapidly in the last few years, and one system that has consistently gained momentum among California homeowners is the FranklinWH aPower S. Known for its whole-home backup capability, strong surge performance, and newly integrated solar capabilities, the aPower S has evolved into a powerhouse competitor to the Tesla Powerwall 3 and the Enphase IQ Battery 5P.
Suppose you are considering adding storage to your home, especially under California’s NEM 3.0 rules. In that case, this review breaks down everything you need to know about the FranklinWH aPower S, including verified specs, pricing, pros and cons, and how it compares to the biggest names in the industry.
FranklinWH aPower S: Quick Summary
Here is a snapshot of the aPower S for fast reference:
- Usable capacity: 15 kWh (Upgraded from previous 13.6 kWh)
- Total capacity: 16 kWh
- Continuous power output: 10 kW (Doubled from previous generation)
- Peak power: 15 kW (10 seconds)
- Battery chemistry: LFP (Lithium Iron Phosphate)
- Warranty: 15 years (Industry Leading)
- Max system size: Up to 15 batteries (225 kWh total)
- Integrated Solar: Yes (Built-in hybrid inverter with 4 MPPTs)
- Best for: Homes needing whole-home backup, heavy load support, and direct solar integration.
What is the FranklinWH aPower S?
The aPower S is the newest addition to FranklinWH’s Franklin Home Power (FHP) ecosystem. Unlike the previous “aPower X” or “aPower 2”, which were AC-coupled batteries, the aPower S is a hybrid system. This means it has a built-in solar inverter, allowing you to connect solar panels directly to the battery unit.
The full system includes:
- aPower S Battery – The 15 kWh energy storage unit with integrated solar inverters.
- aGate – A smart energy management and backup controller.
What sets Franklin apart from many competitors is the aGate. Instead of acting as a basic backup switch, it manages your entire home’s energy flow in real time, controlling:
- Solar energy production
- Battery usage
- Grid input and output
- Generator integration
- Load management for heavy appliances
This allows the system to deliver true whole-home backup without requiring a separate essential loads panel in many installations.
FranklinWH is headquartered in the United States with engineering operations in California. Since entering the U.S. market, the aPower series has earned a strong reputation for reliability, safety, and installer-friendly design.
FranklinWH aPower S Technical Specs (2025 Verified Data)
Below are the up-to-date specifications based on FranklinWH’s current documentation for the aPower S model:
| Specification | FranklinWH aPower S (Corrected) |
| Usable capacity | 15 kWh |
| Continuous power | 10 kW (Discharge) / 8 kW (Charge) |
| Peak power | 15 kW (10 seconds) |
| Surge capability | Excellent; easily starts 5-ton AC units |
| Solar Input | Direct DC Input (4 MPPTs, up to 20 kW PV) |
| Chemistry | LFP (Lithium Iron Phosphate) |
| Round-trip efficiency | 90.5% |
| Operating temperature | -4°F to 131°F |
| Warranty | 15 years or 60 MWh throughput |
| Max per system | 15 units (225 kWh total) |
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If you want to compare these numbers with Tesla’s offering, see our updated Powerwall 3 review: https://nrgcleanpower.com/learning-center/tesla-powerwall-3/
How Much Does the FranklinWH aPower S Cost in 2025?
Because the aPower S includes a built-in solar inverter, it can often save money on the total system cost by eliminating the need for a separate external inverter (like a SolarEdge or SMA unit). Typical installed price ranges for California homeowners are:
| System Size | Installed Cost Range (Estimated) |
| 1 aPower S + aGate | $14,000 to $17,500 |
| 2 batteries | $24,000 to $29,000 |
| 3 batteries | $34,000 to $40,000 |
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These prices usually include:
- The aPower S unit(s)
- aGate controller
- Installation and wiring
- Permitting and inspection
- Software configuration
To better understand where these costs come from, see our full guide on solar battery pricing.
Key Benefits of the FranklinWH aPower S
1. Massive Power Output (10 kW Continuous) Unlike the previous generation which was limited to 5 kW, the aPower S delivers 10 kW of continuous power. This means a single battery is powerful enough to back up most homes, including running air conditioners and electric stoves, without needing to stack multiple units.
2. Built-in Solar Inverter The “S” model connects directly to your solar panels via DC. This is more efficient (fewer energy conversions) and simplifies installation. It features 4 MPPTs, allowing it to handle complex roof layouts and shading issues better than many standard string inverters.
3. Industry-Leading 15-Year Warranty Most home batteries (including Tesla and Enphase) offer a 10-year warranty. FranklinWH has raised the bar with a 15-year warranty and a massive 60 MWh throughput allowance, ensuring the battery lasts significantly longer than the competition.
4. True Whole-Home Backup The aGate controller simplifies whole-home backup, often eliminating the need for a critical-loads subpanel. With 15 kW peak power, it can handle:
- Central air conditioners (up to 5 tons)
- Pool pumps
- Well pumps
- EV chargers
5. Generator Integration The aGate has a dedicated port for a standby generator. It can automatically start the generator when the battery gets low and stop it when solar recharges the system, creating a seamless microgrid.
6. Smart Energy Management The aGate provides load shedding, Time-of-Use optimization, and appliance-level prioritization to maximize savings under NEM 3.0.
FranklinWH aPower S: Pros and Cons
Pros
- High Capacity: 15 kWh per unit (more than Powerwall 3).
- High Power: 10 kW continuous output.
- Best-in-Class Warranty: 15 years.
- Integrated Solar: Reduces equipment and cost.
- Generator Ready: Native integration with gas generators.
- LFP Chemistry: Safer and longer-lasting than NMC.
Cons
- Size: Physically larger than some competitors.
- Availability: As a newer 2025 model, stock may vary by installer.
- App Polish: The software is functional but slightly less polished than Tesla’s interface.
FranklinWH aPower S vs Tesla Powerwall 3 vs Enphase IQ Battery 5P
Here is a quick comparison of today’s most popular storage systems using the corrected 2025 specs:
| Feature | FranklinWH aPower S | Tesla Powerwall 3 | Enphase IQ Battery 5P |
| Usable energy | 15 kWh | 13.5 kWh | 5 kWh (Modular) |
| Continuous output | 10 kW | 11.5 kW | 3.84 kW |
| Peak output | 15 kW (10s) | 11.5 kW (10s) | 7.68 kW (3s) |
| Solar Inverter | Built-in | Built-in | External (Microinverters) |
| Warranty | 15 years | 10 years | 15 years |
| Best for | Whole-home use, Long Warranty, Generators | Tesla Ecosystem, High Power | Small/Modular systems |
For a deeper comparison of the two systems homeowners ask about most, check out this article.
Is the FranklinWH a Power S Worth It in 2025?
For many California homeowners, yes. The Power S has closed the gap with Tesla by doubling its power output and integrating the solar inverter.
The aPower S delivers:
- More energy storage (15 kWh) than a Powerwall 3.
- A significantly longer warranty (15 years vs 10 years).
- Excellent surge capability for AC units.
- Native generator integration that other systems struggle to match.
If your goal is a robust, long-lasting system that can manage solar, batteries, grid, and a generator all in one interface, the FranklinWH aPower S is arguably the most complete package on the market today.
Who Should Choose FranklinWH aPower S?
You may be a great fit for the aPower S if you:
- Want the longest warranty available (15 years).
- Are installing a new solar + battery system (taking advantage of the built-in inverter).
- Have large appliances or a central HVAC system (5-ton AC support).
- Live in an area with frequent outages and want to integrate a gas generator.
- Want to back up your entire home, not just a few circuits.
Final Verdict
The FranklinWH aPower S is one of the most capable home batteries available in 2025. It combines top-tier performance (10 kW continuous / 15 kWh capacity), a market-leading 15-year warranty, and unique generator integration features. While the Tesla Powerwall 3 remains a strong competitor, the aPower S offers superior capacity and warranty coverage, making it a smarter, future-proof choice for many homeowners.