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Tesla Powerwall 3 vs. Enphase IQ 5P vs. FranklinWH aPower 2

By SolarCostData Data Desk · · Corrections log

On the manufacturers’ own spec sheets, these three batteries are built for different jobs, not ranked versions of the same one. The Tesla Powerwall 3 packs 13.5 kWh usable and 11.5 kW continuous with a built-in solar inverter (DC-coupled) — the most power per box. The FranklinWH aPower 2 is the biggest single unit: 15 kWh, 10 kW continuous, AC-coupled, stackable to 225 kWh. The Enphase IQ Battery 5P is the small modular block: 5.0 kWh and 3.84 kVA per unit, AC-coupled through six microinverters, sized in 5-kWh steps. The warranties differ more than the hardware: Tesla gives 10 years to 70% capacity; Enphase 15 years or 6,000 cycles to >60%; Franklin 15 years or 60 MWh of throughput. None of the three publishes a retail price — all are quote-based through installers (Tesla also sells direct). And on a 2026 purchase every one of them gets $0 federal credit — §25D expired December 31, 2025; the 30% §48E credit survives only on third-party-owned systems.
Powerwall 3
13.5 kWh · 11.5 kW · DC-coupled
Enphase IQ 5P
5.0 kWh · 3.84 kVA · AC-coupled
FranklinWH aPower 2
15 kWh · 10 kW · AC-coupled
Longest warranty clock
15 yr (Enphase, Franklin)
Published prices
None — all quote-based
Federal credit if you buy (2026)
$0 — §25D expired

6 min read1,294 words

On this page

Battery comparisons online are mostly vibes with a price widget. This one is deliberately narrower: the manufacturers’ own published specifications for the three systems US installers quote most — the Tesla Powerwall 3, the Enphase IQ Battery 5P, and the FranklinWH aPower 2 — plus the arithmetic those specs support. No stars, no “best overall,” no reseller prices.

A sourcing note, because it matters on a page like this: every figure below is read directly from the manufacturer’s current datasheet (all three retrieved September 2, 2026 — Tesla’s from its document library at energylibrary.tesla.com, since tesla.com itself refuses automated retrieval). The two exceptions are marked in the table: the capacity of Tesla’s Expansion pack and the Powerwall warranty’s retention percentage, which come from Tesla’s separate warranty and expansion documents we could not retrieve directly.

Powerwall 3 vs. IQ Battery 5P vs. aPower 2: the spec table

Table 1: Tesla Powerwall 3 vs. Enphase IQ 5P vs. FranklinWH aPower 2
Tesla Powerwall 3 Enphase IQ Battery 5P FranklinWH aPower 2
Usable energy per unit 13.5 kWh 5.0 kWh 15 kWh (AC)
Continuous power 11.5 kW 3.84 kVA (240 V) 10 kW / 11.5 kVA
Peak / surge 185 LRA motor start 32 A for 3 s (~7.68 kVA); 25.6 A for 10 s; Power Start up to 48 A LRA 15 kW for 10 s; max load start 185 A LRA
Round-trip efficiency 89% (solar→battery→grid); 97.5% solar-to-grid direct 90% AC round-trip (96% DC) 90% (grid–battery–load, beginning of life)
Coupling DC-coupled solar — integrated hybrid inverter, 20 kW solar STC input, 6 MPPTs AC-coupled — six embedded grid-forming microinverters AC-coupled
Chemistry not stated in datasheet — not verified Lithium iron phosphate (LFP) Lithium iron phosphate (LFP)
Warranty 10 years (datasheet); 70% capacity retention per warranty terms — not verified against a Tesla document 15 years or 6,000 cycles (whichever first), >60% capacity 15 years or 60 MWh throughput
Stackability Up to 4 Powerwalls + up to 3 battery-only Expansion units, max 7 units (13.5 kWh per Expansion — not verified against a Tesla document) Modular 5-kWh units; per-system limits set by Enphase system design — not verified here Up to 15 units per aGate — 225 kWh
Published price not verified — sold direct, quoted per address; no manufacturer list price verifiable quote-based — pricing not published quote-based — pricing not published

Efficiency figures are measured under different conditions (Franklin’s at beginning of life, 3 kW, 77°F; Enphase’s as AC round-trip; Tesla’s across the solar path), so read them as “all about 90%” rather than a ranking.

What actually differentiates them

Architecture is the biggest fork. The Powerwall 3 is DC-coupled with a solar inverter built in: on a new solar-plus-storage install it is the inverter, which is elegant and cheap on hardware count — and means the battery and your solar array share one box and one failure point. The Enphase and Franklin units are AC-coupled: they bolt onto any existing solar system (or none), which is why both dominate retrofit quotes. Enphase goes further and builds the battery out of microinverters — six per unit, matching its microinverter-based solar architecture.

Sizing granularity versus ceiling. Enphase sizes the IQ Battery 5P in 5-kWh steps, so a household can buy exactly the arbitrage capacity its time-of-use spread justifies — the finest-grained sizing of the three. Franklin has the largest single unit and by far the largest published ceiling: 225 kWh behind one aGate controller, a figure aimed at large homes and generator replacement. Tesla sits between, with power-less 13.5-kWh expansion packs that share the lead unit’s inverter — capacity grows, but the 11.5 kW output does not.

Whole-home versus partial backup follows from power, not marketing. One Powerwall 3 (11.5 kW, 185 LRA) or one aPower 2 (10 kW, 185 A LRA) is specified to start and carry central air conditioning and whole-home loads; a single 3.84-kVA Enphase 5P is, by its own numbers, an essential-loads battery, and Enphase whole-home designs use several units in parallel. Whether your panel can be backed up whole is a load-calculation question for the installer either way.

The warranty structures reward different owners. Convert them to common units and the differences are real: Enphase’s 6,000-cycle cap on a 5-kWh unit is roughly 30 MWh of lifetime throughput; Franklin’s 60 MWh on a 15-kWh unit is about 4,000 full-cycle equivalents — the largest per-unit energy allowance of the three, and 15 years on both clocks. Tesla’s datasheet states simply “10 years,” with no cycle or throughput cap; the retention figure (70%) sits in Tesla’s separate warranty document, which we could not retrieve directly. A battery cycled hard daily for arbitrage eats throughput allowances; a backup-only battery mostly eats calendar years. Pick the warranty shaped like your usage.

Nobody publishes a price. Enphase and FranklinWH sell through installers, quote-based. Tesla quotes per address through its direct channel. Every specific dollar figure in circulation is a reseller’s or a blog’s, which is why none appears here — compare installed quotes, not list prices, and remember the hardware is typically only part of the installed cost.

The 2026 money framing: §48E, TPO, and the closed rebate

Brand choice is the second decision. The first is ownership structure, because the tax treatment changed underneath the market. Buy any of these in 2026 and your federal credit is $0 — §25D expired December 31, 2025. The 30% that survives is §48E , a business credit that belongs to whoever owns the equipment, which on a purchase is never you. It can reach a homeowner only through a lease, PPA or provider-owned arrangement — third-party ownership — and only as whatever share of it the provider bakes into the monthly fee. Whether that trade beats paying full freight for an owned system is exactly what the buy vs. third-party-owned calculator computes, in present value, with the arbitrage and backup cases priced separately.

California buyers should also strike one line from older advice: SGIP is closed. As of late August 2026 the storage budget is exhausted and every step is fully subscribed, equity tiers included. A quote still subtracting an SGIP rebate is quoting money that no longer exists — ask for it re-run without that line. The battery case in California now rests on NEM 3.0’s export rates , which reward storing your solar instead of exporting it.

How to use this page

Decide capacity and power from your loads and your rate plan first — the battery worth-it guide and battery calculator do that math. Then let the table above narrow the brand: DC-coupled new-build with maximum power per box points one way; modular retrofit in small steps another; single-box whole-home scale with the biggest throughput warranty a third. Get every quote as an installed, permitted, all-in number, and read the warranty’s cycle or throughput clause against how hard you actually plan to cycle it.

Sources

Specifications change with hardware revisions and regional SKUs — confirm the current datasheet for your market before purchase. Figures here are the manufacturers’ published ratings, not measurements. Nothing here is tax, legal or financial advice.

Frequently asked questions

Which home battery has the most capacity per unit?

The FranklinWH aPower 2, at 15 kWh AC per unit, ahead of the Tesla Powerwall 3 at 13.5 kWh usable. The Enphase IQ Battery 5P holds 5.0 kWh per unit by design — it is meant to be installed in multiples, so system capacity is a design choice in 5-kWh steps rather than a property of the box.

Which battery can back up a whole house on its own?

Judged purely on continuous output, the Powerwall 3 (11.5 kW, 185 LRA motor start) and the aPower 2 (10 kW, 185 A LRA) are sized for whole-home loads including air conditioning from a single unit. A single Enphase 5P (3.84 kVA) is an essential-loads unit; whole-home backup on Enphase means several units in parallel. Panel capacity, feeder sizing and your largest motor load decide the real answer — that is an installer calculation, not a brochure one.

Whose warranty is actually the strongest?

They are structured too differently for one winner. Tesla warrants 10 years to 70% remaining capacity, with no cycle or throughput figure in its published datasheet material. Enphase warrants 15 years or 6,000 cycles, whichever comes first, to >60% capacity — about 30 MWh of equivalent throughput on a 5-kWh unit. Franklin warrants 15 years or 60 MWh of throughput — the largest energy allowance per unit (about 4,000 full cycles of a 15-kWh pack), and a heavy-cycling household can consume a throughput allowance well before year 15. Match the structure to how hard you will cycle the battery.

What do these batteries cost in 2026?

None of the three manufacturers publishes a standalone retail price: Enphase and FranklinWH sell through certified installers, quote-based, and Tesla sells direct with pricing generated per address and configuration. Any specific dollar figure you see elsewhere is a reseller’s or blog’s number, not the manufacturer’s. Get the installed, permitted, all-in quote — hardware list price is a minority of what you pay anyway.

Can I still get the 30% federal credit on a home battery in 2026?

Not by buying one. The residential credit (§25D) expired for property placed in service after December 31, 2025, so a 2026 cash or financed purchase of any of these systems gets $0 federal credit. The 30% that survives is §48E, a business credit claimed by whoever owns the equipment — it can reach you only through a lease, PPA or provider-owned arrangement, and only as whatever discount the owner passes through. Confirm your position with a tax professional; this is not tax advice.

Does California's SGIP rebate still apply to these batteries?

No. SGIP’s storage budget is exhausted and closed to new residential applications as of late August 2026 — every step fully subscribed, equity tiers included. A 2026 California quote that still subtracts an SGIP rebate is using money that no longer exists. The program has reopened with new budget cycles before, so check its status page, but do not budget for it.

Sources: U.S. Energy Information Administration (EIA) electricity rates · DSIRE incentive records · public IRS/OBBBA guidance. Figures are modeled estimates, not quotes or tax advice. See our methodology.

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