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The best home battery for backup power is the one whose continuous output (kW) covers the loads you run at the same time and whose capacity (kWh) covers the hours you want to ride through. Among the batteries we reviewed, the Tesla Powerwall 3 and FranklinWH aPower 2 offer the highest output from a single unit, and Enphase IQ Batteries are the most modular. All figures below come from manufacturer documents or the published analyses we name, as of October 24, 2026.
We have not tested these batteries. Our picks rest on specs, certifications, warranties and published expert and installer-marketplace analyses. See how we pick products.
Quick picks
| Best for | Pick | Capacity | Continuous power | Warranty |
|---|---|---|---|---|
| Most output from one unit | Tesla Powerwall 3 | 13.5 kWh (nominal) | 11.5 kW | 10 years |
| Largest single-unit capacity, rugged outdoor install | FranklinWH aPower 2 | 15 kWh | 10 kW | 15 years / 60 MWh |
| Midsize modular backup | Enphase IQ Battery 10C | 10 kWh | 7.08 kW | 15 years / 6,000 cycles |
| Starting small, adding later | Enphase IQ Battery 5P | 5.0 kWh | 3.84 kW | 15 years / 6,000 cycles |
Sources: Tesla Powerwall 3 datasheet (nominal energy; the datasheet does not state usable energy), FranklinWH aPower 2 product page (15 kWh stated without specifying usable), Enphase IQ Battery 10C and IQ Battery 5P.
What does a backup battery actually have to do?
Two numbers decide backup performance:
- Power (kW): the most the battery can deliver at one moment. Add up everything that might run together: refrigerator, lights, internet, well pump, furnace blower, an air conditioner.
- Energy (kWh): how long that power lasts. Hours of backup = usable kWh ÷ average kW load.
Example (an illustration with assumed numbers, not a measurement): a home that averages 1.5 kW of essential loads for a 12-hour overnight outage needs 1.5 × 12 = 18 kWh. One 13.5 kWh battery would run out in about 9 hours (13.5 ÷ 1.5) before any solar recharge. See how to size a home battery for the full method, and our earlier battery sizing guide for a lighter-load example.
Product cards
Tesla Powerwall 3 — best for high output from one unit
Tesla’s datasheet lists 13.5 kWh nominal energy, 11.5 kW maximum continuous discharge, a 10-year warranty, an operating range of -4°F to 122°F (derating possible above 104°F) and up to 20 kW of solar input across six MPPTs. It lists UL 1741, UL 9540, UL 9540A and UL 1973 among its certifications. Tesla’s own product page says it includes an integrated solar inverter.
Pros
- Highest continuous output of the batteries we compared.
- Integrated inverter means one box can handle solar and storage in a new install.
- Broad UL certification list on the datasheet.
Cons
- Shortest warranty of the four (10 years).
- Datasheet states nominal, not usable, energy.
- Tesla’s public pages do not list a price; installed cost varies by installer.
Approximate price: EnergySage’s April 2026 battery ranking lists $998 per kWh; Solar.com’s battery guide reports a median of about $15,000 installed with solar (September 2026 installer price lists, before incentives). Prices checked October 24, 2026.
FranklinWH aPower 2 — best for capacity and tough sites
FranklinWH’s product page lists 15 kWh capacity, 10 kW continuous power, a 15-year warranty covering 60 MWh of throughput, IP67 dust and water protection, LFP chemistry and an operating range of -4°F to 131°F. It says up to 15 units can stack per aGate controller. The page does not state peak power or a UL 9540 listing, so ask your installer for the certification documents.
Pros
- Largest single-unit capacity here.
- Long warranty and an IP67 rating.
- FranklinWH says a single unit can start a 5-ton air conditioner.
Cons
- Certifications are not stated on the product page we read.
- The page does not say whether 15 kWh is usable energy.
- Uses FranklinWH’s own aGate controller, so it is a different ecosystem from Tesla or Enphase.
Approximate price: EnergySage lists $1,177 per kWh; Solar.com reports about $17,250 median installed with solar (before incentives). Prices checked October 24, 2026.
Enphase IQ Battery 10C — best for midsize modular backup
Enphase’s product page lists 10 kWh, 7.08 kW continuous power and a 15-year warranty covering up to 6,000 cycles. It cites UL 9540A certification. A third-party comparison from NuWatt Energy describes it as AC-coupled and best suited to homes already using Enphase microinverters; we did not confirm the coupling on Enphase’s own page.
Pros
- Long warranty for the capacity.
- Modular: more units can be added.
- Natural fit with Enphase microinverter systems.
Cons
- Lower continuous power than a single Powerwall 3 or aPower 2.
- The Enphase page does not state operating temperature.
- Highest per-kWh price among the batteries EnergySage ranks here (see below).
Approximate price: EnergySage lists $1,404 per kWh; Solar.com reports about $14,250 median installed with solar. Prices checked October 24, 2026.
Enphase IQ Battery 5P — best for starting small
The IQ Battery 5P lists 5.0 kWh usable capacity, 3.84 kW continuous power, 7.68 kW peak for 3 seconds and 6.14 kW for 10 seconds, six embedded grid-forming microinverters and a 15-year warranty up to 6,000 cycles. Backup requires an IQ System Controller 3 or 3G, and commissioning requires an Enphase-certified installer.
Pros
- Small steps: add units as budget allows.
- Enphase states usable (not nominal) capacity.
Cons
- You may need several units for whole-home backup, and the controller adds cost.
- Solar.com’s median for a no-backup version is about $6,125, but about $10,650 with backup, so the backup hardware matters.
What about owner reviews?
We looked for large, independent owner-satisfaction data on the batteries themselves and did not find a source we trust. Solar.com’s analysis covered 158,781 Google and Yelp reviews of California solar installers, 8,124 of which mention a battery, but it says those ratings reflect installer performance, not battery quality. Treat installer reputation as its own decision, and see how to compare solar quotes.
Who should skip a battery
- Outages are rare and short. A battery is expensive insurance. If you mostly need to keep a phone, router and refrigerator going, a smaller system, or no battery, may do.
- You are on a flat rate with generous net metering. A battery adds little bill savings there. See net metering by state.
- You plan to run a large well pump or central air for days. Batteries ride through outages; they do not replace a generator for multi-day events unless sized and recharged by solar.
- You expect a federal tax credit. The credit for batteries placed in service after December 31, 2025 has ended (below).
Incentives: what changed
The IRS says the residential clean energy credit is not available for property placed in service after December 31, 2025. Storage of at least 3 kWh used to qualify. State incentives, utility battery programs and different rules for leased systems may still apply. Check your state’s page in Rates by State and ask your installer for the written basis of any incentive they quote. Confirm eligibility with a qualified tax professional.
Buying checklist
- Critical loads and their kW. List what must run at once, including starting surges.
- Hours of backup. Hours = usable kWh ÷ average kW.
- Existing solar. Same-brand microinverters or a new hybrid system change which battery fits.
- Budget at full price. Get at least three written quotes with equipment model numbers.
- Climate and location. Compare operating temperature ranges and outdoor ratings.
- Warranty. Compare years and any cycle or throughput cap.
- Utility rules. Interconnection approval and export rules vary by utility; see our rate and policy guides.
- Certifications. Ask for UL 9540 documentation for the exact model.
Limitations
Figures are manufacturer-stated, sometimes nominal rather than usable, and prices are approximate installed medians or per-kWh figures from marketplaces, not quotes. Prices vary by home, utility and installer. This is not tax or engineering advice.
Sources
- Tesla Powerwall 3 datasheet (accessed Oct 24, 2026)
- FranklinWH aPower 2 (accessed Oct 24, 2026)
- Enphase IQ Battery 10C and IQ Battery 5P (accessed Oct 24, 2026)
- EnergySage, Best solar batteries for your home in 2026 (updated Apr 29, 2026)
- Solar.com, The Best Solar Batteries (updated Oct 1, 2026)
- IRS, Residential Clean Energy Credit
- NuWatt Energy comparison (secondary)
Related: Do solar panels work in a power outage? · Time-of-use rates and solar
Frequently asked questions
What is the best home battery for backup power?
For a single unit that can carry most of a home, the Tesla Powerwall 3 (11.5 kW continuous, 13.5 kWh nominal) and FranklinWH aPower 2 (10 kW continuous, 15 kWh) have the highest output of the batteries we reviewed. Enphase IQ Batteries are better when you want to add capacity in small steps or already have Enphase microinverters.
How many batteries do I need to back up a whole house?
It depends on the loads you want to run at once (kW) and for how long (kWh). Add up the loads, divide your target energy by one battery's capacity and round up. Our battery sizing guide walks through the formula.
Is there still a federal tax credit for home batteries?
The IRS says the residential clean energy credit is not available for property placed in service after December 31, 2025. State, local and utility programs may still apply. Confirm eligibility with a qualified tax professional.
Can a home battery run central air conditioning?
Sometimes. Starting a compressor needs a short surge well above its running power. Tesla's datasheet lists the ability to start loads up to 185 LRA, and FranklinWH says the aPower 2 can start a 5-ton A/C. Confirm your specific unit's starting current with your installer.
