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NuWatt designs, installs, and manages solar, battery, heat pump, and EV charger systems across 9 states. One company, one warranty, one point of contact.
Get a Free QuoteWhich is better for your home? Compare storage, power, warranty and installed-cost scope—with manufacturer sources and clear trade-offs.
US model specifications checked October 18, 2026
Tesla Powerwall 3
$15,400 installed*
Earlier guide estimate; current quote required
13.5 kWh
Up to 11.5 kW continuous AC
FranklinWH aPower 2
$17,500 installed (with aGate)*
Earlier guide estimate; current quote required
15 kWh
Up to 10 kW continuous AC
Neither battery is the best choice for every home. aPower 2 stores 15 kWh versus 13.5 kWh—about 11.1% more energy per unit. Powerwall 3 supplies up to 11.5 kW versus 10 kW continuous AC output and includes a solar inverter. The right choice depends on your loads, existing solar, controller design and comparable installed quotes—not an unverified star rating.
Integrated solar + storage
An integrated solar inverter can simplify a new solar-and-battery design. Existing equipment and backup loads still need a compatibility review.
AC-coupled storage + controls
More energy per unit, with AC-coupled solar integration. Specify the controller, load controls and any generator integration in the proposal.
*These installed-price estimates are retained from the earlier version of this guide—not current NuWatt offers or verified project quotes. Equipment, electrical work, permits and site conditions affect the final price. See pricing and scope below.
*FranklinWH capacity retention is limited by 15 years or 60 MWh, whichever comes first. Controller coverage differs. Both manufacturers’ full conditions apply; this is not a blanket system or roof warranty.
US Powerwall 3 model 1707000-xx-y and aPower 2 APR-10K15V2-US. Confirm the exact ordered SKU. Continuous power, short-duration peaks and motor-start current describe different limits.
| Specification | Tesla Powerwall 3 | FranklinWH aPower 2 |
|---|---|---|
| Usable Capacity | 13.5 kWh AC per unit | 15 kWh AC per unit |
| Continuous Power | Up to 11.5 kW AC; configuration-dependent | Up to 10 kW AC / 11.5 kVA; configuration-dependent |
| Peak Power | 185 A LRA motor-start capability for 1 second; not a peak-kW rating | Off-grid, at the rated 11.5-kVA configuration: up to 15 kW for 10 seconds; 25 kW transient for 1 second; 185 A LRA motor-start capability |
| Round-trip Efficiency | 89%: solar → battery → home/grid | 90%: grid → battery → load |
| Chemistry | Rechargeable lithium-ion; confirm model-specific chemistry with Tesla | Lithium iron phosphate (LFP) |
| Weight | 291.2 lb (132 kg), installed with cover and bracket | 357 lb (162 kg), complete; 335 lb (152 kg) without cover |
| Dimensions | 43.5 × 24.0 × 7.6 in (H × W × D) | 45.2 × 29.5 × 11.8 in (H × W × D) |
| Operating Temp | −20°C to 50°C; output can derate above 40°C | −20°C to 50°C; up to 55°C at 5 kW derated output |
| Connectivity | Tesla app; Wi-Fi, Ethernet and cellular; internet required under warranty terms | FranklinWH app; communications and controller depend on the chosen system |
| Solar Integration | Integrated solar inverter; up to 20 kW DC solar input | AC-coupled; works with a separately specified solar inverter |
| Expansion | 13.5 kWh per Expansion; up to 3 Expansion units, subject to system design | Up to 15 aPower 2 units / 225 kWh per aGate, subject to system design |
| Equipment Warranty | 10-year limited warranty; 70% capacity retention, subject to use and connectivity terms | 15-year limited defect warranty; 70% capacity retention at 15 years or 60 MWh, whichever comes first |
Efficiency values use different energy paths and test conditions; 89% versus 90% is not a like-for-like efficiency ranking. Current installation specifications take precedence over older marketing figures.
Tesla Powerwall 3 — current US installation specifications; FranklinWH aPower 2 US datasheet — October 9, 2026.
aPower 2: 15 kWh vs 13.5 kWh
That is 1.5 kWh, or about 11.1%, more stored energy per unit—not a guarantee of longer backup for every load profile.
Powerwall 3: up to 11.5 kW vs 10 kW
At those configured outputs, Powerwall 3 provides 15% more continuous AC power. Check circuit design, temperature and startup loads.
10 years vs 15 years—with conditions
Read retention, throughput, registration, connectivity and exclusions, not just the headline term. aGate and communications equipment have separate coverage.
Compare the complete system, not the battery alone
Powerwall 3 integrates a solar inverter. FranklinWH is AC-coupled; controller options and generator/load-control accessories must be specified.
No verified price winner without matched quotes
Compare the same scope: battery quantity, controller, electrical work, permits, commissioning and service. The scenario below is arithmetic, not an offer.
Capacity advantage: FranklinWH. Configured continuous-output advantage: Tesla. Price and overall fit: project-specific. We do not convert these trade-offs into unsupported customer ratings or an overall winner.
Installed cost is more than battery hardware. Ask for itemized equipment, controller, electrical and civil work, permits, commissioning and service terms. Current prices and delivery dates require confirmation.
The earlier guide listed $15,400 installed for one Powerwall 3 and $17,500 installed with an aGate for one aPower 2. We retain those estimates for comparison, with a $2,100 difference. They have not been verified against current project quotes and are not current NuWatt offers. Equivalent installation scope has not been established; no incentives are deducted.
| System | Installed estimate* | Usable energy | Estimate per kWh* |
|---|---|---|---|
| Tesla Powerwall 3 | $15,400 installed | 13.5 kWh | $1,141/kWh |
| FranklinWH aPower 2 | $17,500 installed (with aGate) | 15 kWh | $1,167/kWh |
*Rounded cost per kWh is the earlier guide estimate divided by 13.5 kWh or 15 kWh, not a battery-only hardware price or a like-for-like quote. The Franklin figure includes an aGate; confirm the Tesla islanding equipment and both systems’ installation scope in writing. Solar panels, service upgrades, trenching, taxes and other site-specific work must be itemized, not assumed included.
A lower quote is not automatically better value. Verify usable storage, configured power, backup circuits, any necessary service upgrade, warranty responsibilities and the exact controller before comparing totals.
Consider before choosing
Consider before choosing
Want to evaluate an integrated solar inverter for a new solar-plus-storage project; need higher configured continuous output between these two units; prefer the Tesla app; or want to plan for additional storage through Powerwall 3 Expansion units.
Prioritize 15 kWh per unit; want to assess AC-coupled storage alongside existing solar; or need a system design that includes specified generator and load-control functions. Evaluate controller choices and accessories rather than assuming every feature is included.
Whole-home backup is a design outcome. Central air, well pumps, electric heat and EV charging can exceed a single unit’s power or stored-energy budget. Size simultaneous loads, motor starts, reserve and outage duration before promising what stays on.
Powerwall 3 combines a battery and solar inverter, but that does not establish a fixed inverter-cost saving or make every existing solar design compatible. Specify the islanding equipment, electrical work, battery location and commissioning. Obtain a project-specific installation and outage schedule; this guide does not promise a 4–6-hour installation or a universal equipment lead time.
aPower 2 is indoor/outdoor rated: Type 3R enclosure, IP67 battery pack/inverter and IP56 wiring compartment. That is not permission to install anywhere or omit required protection. Follow siting and mounting instructions for the specified controller configuration. aGate-based systems and Meter Adapter Controller alternatives have different scopes; confirm generator and load-control accessories explicitly.
FranklinWH aGate 1.3/1.3.1 + aPower 2 installation guide — October 8, 2026; FranklinWH solar-retrofit configuration with Meter Adapter Controller.
Warranty clarity: battery and controller manufacturer warranties are separate from installation workmanship and roof coverage. NuWatt coverage is defined by your signed agreement; existing customers may have different terms and should refer to their own contracts.
Our Recommendation
Neither battery is the best choice for every home. aPower 2 stores 15 kWh versus 13.5 kWh—about 11.1% more energy per unit. Powerwall 3 supplies up to 11.5 kW versus 10 kW continuous AC output and includes a solar inverter. The right choice depends on your loads, existing solar, controller design and comparable installed quotes—not an unverified star rating.
Start with a load assessment and two comparable configurations. NuWatt can help you compare the equipment, electrical scope and written coverage before choosing.
Neither is the best choice for every home. aPower 2 provides 15 kWh versus 13.5 kWh per unit, about 11.1% more stored energy. Powerwall 3 provides up to 11.5 kW versus 10 kW continuous AC output. Compare backup loads, existing solar equipment, expansion plans, controller configuration and an itemized installed quote. Neither nameplate figure guarantees whole-home backup.
The earlier guide listed $15,400 installed for one Powerwall 3 and $17,500 installed with an aGate for one aPower 2, a $2,100 difference. These retained guide estimates have not been verified against current project quotes and are not current NuWatt offers. They work out to about $1,141 and $1,167 per usable kWh, respectively, before any incentives. The two systems store different amounts of energy, and equivalent installation scope has not been established. Compare controller, electrical, permit, installation and commissioning scope in a current itemized quote before choosing on price.
Powerwall 3 has a 10-year limited warranty with 70% capacity retention. Unlimited cycles apply to the specified self-consumption, time-based-control and backup uses; other applications have a 37.8 MWh limit. aPower 2 has a 15-year limited defect warranty and 70% capacity retention at 15 years or 60 MWh throughput, whichever comes first. Franklin controllers and communications hardware have separate terms. Registration, internet connectivity, use and exclusions matter. Manufacturer coverage is separate from NuWatt workmanship; your signed agreement controls any NuWatt coverage, and existing customers may have different terms.
Ask NuWatt to confirm the exact product, current installer credentials and equipment availability for your project. Manufacturer installation requirements do not themselves establish an installer’s authorization. Your written proposal should identify the battery, controller, electrical work, commissioning and service responsibilities before you approve the installation.
We do not have a verified customer-sales ranking to publish here. Popularity is not a substitute for a load assessment: compare the 13.5 kWh and 15 kWh storage capacities, continuous power, existing solar compatibility, warranty conditions and project-specific installed scope.
Tesla specifies 13.5 kWh per Powerwall 3 Expansion, with up to three Expansion units subject to the supported system design; adding energy capacity does not automatically add inverter output. Franklin specifies up to 15 aPower 2 units per aGate, totaling 225 kWh. Expansion still depends on controller compatibility, electrical capacity, siting, permitting and manufacturer instructions. Confirm the future design before buying the first unit.
Our energy advisors can help you compare both systems for your home, budget and energy goals.
Checked October 18, 2026. US model scope; figures are manufacturer ratings, not a site-specific performance guarantee. Datasheets, installation requirements and limited warranties can change. Images are illustrative, not to scale.