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The short answer
For most homeowners adding solar-plus-storage for the first time, the Tesla Powerwall 3 wins on integrated solar inverter, price, and service network. For homeowners retrofitting storage onto existing solar (especially with a non-Tesla inverter), the FranklinWH aPower 2 wins on capacity per unit, warranty length, and AC-coupling flexibility.
Side-by-side spec comparison
| Specification | Tesla Powerwall 3 | FranklinWH aPower 2 |
|---|---|---|
| Usable capacity (single unit) | 13.5 kWh | 15.0 kWh |
| Continuous output | 11.5 kW | 10.0 kW |
| Surge output | 185 LRA | 150 LRA |
| Chemistry | LFP | LFP |
| Round-trip efficiency | 90% | 91% |
| Integrated solar inverter | Yes (up to 19.2 kW DC) | No (AC-coupled only) |
| Stackability | Up to 4 units (54 kWh) | Up to 15 units (225 kWh) |
| Warranty | 10 years / 70% capacity | 12 years / 6,000 cycles |
| Typical installed cost | $11,500–$13,500 | $13,500–$15,500 |
Where the Powerwall 3 wins
The Powerwall 3's biggest advantage is the integrated solar inverter — if you're adding solar and storage together, you skip a separate string inverter ($2,000–$3,500 savings) and have one less point of failure. The 11.5 kW continuous output is also the highest in the residential segment, enough to start a 4-ton central AC compressor. Tesla's installer network is the largest in the country (38+ states), and the Tesla app is the most polished in the industry.
Where the FranklinWH aPower 2 wins
The FranklinWH aPower 2 wins on three dimensions. First, capacity per unit: 15 kWh vs Tesla's 13.5 kWh — 11% more storage in the same physical footprint. Second, stackability: up to 15 units (225 kWh) vs Tesla's 4 units (54 kWh). For large off-grid or whole-home backup systems, FranklinWH scales far further. Third, warranty: 12 years vs Tesla's 10, with explicit 6,000-cycle coverage. FranklinWH is also AC-coupled, making it the natural choice for retrofitting onto existing solar with any inverter.
Decision framework
- Choose Tesla Powerwall 3 if: You're adding solar and storage together (integrated inverter saves money), you want whole-home backup including central AC, or you value the largest installer network.
- Choose FranklinWH aPower 2 if: You're retrofitting onto existing solar (especially non-Tesla inverter), you need 30+ kWh of storage, or you want the longest warranty in the segment.
For full details on both batteries, see our best home batteries of 2026 comparison.
Complementary products
Sense Energy Monitor (with Solar)
Validates your Tesla system's per-circuit performance and catches issues the Tesla app doesn't surface.
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Emporia Vue 3 Energy Monitor
Budget-friendly per-circuit monitoring that pairs naturally with FranklinWH's AC-coupled architecture.
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