Powerwall 3, Enphase IQ Battery 10C and FranklinWH aPower 2 solve similar storage problems with different system designs. Compare usable energy, continuous output, backup equipment, compatibility and the complete installed quote. The largest single battery is not automatically the right system for your home.
This is a U.S.-focused specification and buying comparison reviewed November 14, 2026. We have not bench-tested these products. Manufacturer ratings describe specified conditions; your installer must confirm the exact model, configuration and local approval. The featured image illustrates quote comparison rather than showing synthetic branded products.
The core numbers, side by side
| Single battery system | Published energy | Published continuous output | Design question |
|---|---|---|---|
| Tesla Powerwall 3 | 13.5kWh nominal AC battery energy | Up to 11.5kW AC; commissioned rating can be lower | How will its integrated solar inverter and backup hardware fit your installation? |
| Enphase IQ Battery 10C | 10kWh usable energy | 7.08kW in the manufacturer launch specification | Which compatible system components and approved grid-isolation arrangement are included? |
| FranklinWH aPower 2 | 15kWh published capacity | 10kW | Which aGate/controller, solar integration and load-management configuration is quoted? |
Energy in kWh describes the size of the store. Power in kW describes how quickly energy can be delivered. A system might store enough energy for a refrigerator overnight yet be unable to start another large appliance at the same time. Conversely, high output does not provide unlimited runtime.
These are not interchangeable specification labels. Tesla explicitly describes nominal AC energy under stated test conditions; Enphase publishes usable energy; FranklinWH’s product page gives capacity. Ask each installer for expected AC energy delivered to your backed-up loads at the relevant temperature, reserve and age. Do not apply one efficiency number blindly to all three.
Worked example: the overnight target comes first
Suppose your essential loads average 500W for 12 hours with no solar recharge. Required delivered energy is 0.5kW × 12h = 6kWh. If you add an illustrative 20% planning margin, your target becomes 7.2kWh delivered. The margin is our chosen scenario allowance, not a manufacturer reserve requirement.
At the simplest arithmetic level, dividing the published capacities by 0.5kW gives 27 hours for Powerwall 3, 20 hours for IQ Battery 10C and 30 hours for aPower 2. These are capacity-division comparisons only, not verified outage runtimes. Actual starting charge, unavailable reserve, conversion boundaries, standby use, temperature and battery age alter the delivered result.
Ask all three bidders to demonstrate the same 7.2kWh target and the same simultaneous/startup loads. That is more useful than comparing three different “whole-home backup” promises. For a more detailed outage scenario, see our hour-by-hour Powerwall guide.
Price: compare a complete system, not a battery-only number
A third-party Powerwall 3 guide lists hardware from $9,200 and reports installed estimates of $11,500–$16,500. Treat these as attributed provisional estimates checked on the review date, not a Tesla quote or verified national average. Tesla’s own ordering process requires a property-specific quote. No incentive is deducted here.
We have not verified comparable complete installed prices for Enphase 10C and FranklinWH aPower 2 for the same property and scope, so their prices are quote-dependent. Filling that gap with a guessed range would create a false ranking. Request all bids against one written specification.
| Quote line | Why it belongs in every bid |
|---|---|
| Battery quantity and exact model | One unit is not an equal-capacity system across these brands. |
| Backup/isolation and control hardware | Storage alone does not establish safe blackout operation. |
| Solar compatibility work | An existing inverter may be retained, integrated differently or require changes. |
| Electrical, siting and permitting work | Panel work, cable routes and local requirements affect total cost. |
| Labor, tax, commissioning and support | Compare the full amount payable and who resolves faults. |
| Excluded work | Ask what would trigger a change order before accepting. |
Warranty years are only one part of the comparison
Tesla’s U.S. warranty describes ten years and 70% retained capacity, with operating-mode and throughput conditions. Enphase announced a 15-year limited warranty for its fourth-generation system. FranklinWH advertises 15 years and 60MWh throughput for aPower 2. Those headlines do not establish equivalent coverage.
Obtain the warranty PDF applicable to the exact equipment and purchase date. Compare the retained-capacity threshold, cycles or throughput limit, permitted use, connectivity obligations, transfer rules and whether labor, shipping or removal/reinstallation are included. Read “whichever comes first” language where present. An installer’s workmanship warranty is separate from the battery manufacturer’s warranty.
Choose by the problem you need solved
New solar plus battery: include Powerwall 3’s integrated solar-inverter design in the comparison, but ask whether the proposed array and backup arrangement fit. Integrated hardware can change the scope; it does not automatically make the total quote cheaper.
Existing solar: request written compatibility for your inverter model and system generation. Enphase’s newer integration options include certain third-party solar configurations, but that is not blanket compatibility with every existing installation. Confirm the permitted configuration and local utility approval.
Larger single-unit energy target: aPower 2’s published 15kWh capacity is worth examining, alongside delivered-energy assumptions, controller costs and local service. More nameplate capacity is only helpful if the proposed system meets your output and installation requirements.
Long outages: compare daily recharge potential and essential-load reduction. Adding batteries extends stored energy; it does not create new energy during several poor-solar days. Our whole-home versus essential-load checklist helps define what must remain on.
Questions that can change the winner
Can the selected system restart solar after a prolonged outage? What happens at low battery charge? Which loads are automatically shed? What internet functions remain available offline? Who responds locally to a fault, and what is the expected service process? Ask each bidder to answer in writing for the exact design rather than copying a generic brochure.
For a small critical load, first use the fridge-runtime calculator and measured energy. You may discover that your immediate need is much smaller than a whole-home installation—or that heating and pumps make it significantly larger.
The short version
Shortlist all three by your delivered-energy target, peak demand, existing solar and service availability. Compare complete quotes and warranty conditions on the same basis. Published kWh and kW begin the comparison; they do not finish it.
Primary references: Tesla Powerwall 3 U.S. datasheet; Tesla U.S. warranty; Enphase IQ Battery 10C launch specifications; Enphase third-party solar integration announcement; FranklinWH aPower 2 specifications.
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