The short answer
- Tesla Powerwall 3: 13.5 kWh with a built-in solar inverter and up to 11.5 kW of power; 10-year warranty to 70% capacity.
- Enphase IQ Battery 5P / 10C: modular 5 or 10 kWh units that pair with Enphase microinverters; 15 years or 6,000 cycles to 60%.
- FranklinWH aPower 2: 15 kWh and 10 kW per unit; 15 years or 60 MWh.
- The best choice depends on your existing solar, how much backup power you need, and the installer's experience with it.
Specs side by side
| Battery | Usable energy | Continuous power | Warranty |
|---|---|---|---|
| Tesla Powerwall 3 | 13.5 kWh | Up to 11.5 kW (5.8–11.5 kW settings) | 10 years; 70% capacity at 10 years |
| Enphase IQ Battery 5P | 5.0 kWh per unit | 3.84 kVA (7.68 kVA peak) | 15 years or 6,000 cycles; over 60% |
| Enphase IQ Battery 10C | 10.0 kWh per unit | 7.08 kVA | 15 years or 6,000 cycles; 60% |
| FranklinWH aPower 2 | 15 kWh per unit | 10 kW (15 kW for 10 s) | 15 years or 60 MWh |
From each maker's datasheet or warranty, checked Oct 1, 2026. Tesla says its full 10-year warranty depends on the Powerwall staying connected to the internet (warranty).
How to choose
- New solar plus battery: Powerwall 3 combines the battery and solar inverter, which can simplify the job. Enphase suits roofs that need microinverters (shade, several roof faces).
- Adding to existing solar: an AC-coupled battery (Powerwall 3 with expansion, Enphase, FranklinWH) works with most existing inverters. See adding a battery.
- Backup power: check the continuous and surge power if you want to run air conditioning or a well pump in an outage, not just the kWh.
- Installer: pick an installer who installs that battery often, and ask how many they have put in.
LFP (lithium iron phosphate) chemistry, used by Enphase and FranklinWH, has become common in home batteries. Every battery must meet the fire code limits on location and size (permits).
Checked against official sources on Oct 1, 2026. Sources are linked in the text. Not legal, tax or financial advice.