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

Shopping for a home battery in 2026 feels like comparing phones by reading only the marketing pages. The spec sheets look similar — kilowatt-hours here, kilowatts there — but the numbers that aren't printed matter just as much as the ones that are. This comparison puts the three most-discussed residential batteries — the Tesla Powerwall 3, the Enphase IQ Battery 5P, and the FranklinWH aPower 2 — side by side using only manufacturer-published specifications. It is a spec-based comparison, not a hands-on test: nobody here tore these units apart or ran them through a lab. What makes it useful anyway is honesty about what each manufacturer declines to publish.

The short version: what actually differs

Strip away the branding and three things separate these batteries: how much energy each unit stores (kWh), how much power it can deliver at once (kW, continuous and peak), and how the warranty is structured. Efficiency figures are the murkiest part — one maker publishes a 90% round-trip number, one publishes a different kind of efficiency entirely, and one publishes nothing at all. Those gaps are not accidents, and you should know about them before you sign a quote.

Side-by-side specs (manufacturer-published only)

	Tesla Powerwall 3	Enphase IQ Battery 5P	FranklinWH aPower 2
Usable capacity (per unit)	13.5 kWh	5.0 kWh	15 kWh AC
Continuous power	11.5 kW (US rating)	3.84 kW	10 kW (11.5 kVA)
Peak power	Not published	7.68 kW for 3 s / 6.14 kW for 10 s	15 kW for 10 s
Warranty	10 years	15-year limited, up to 6,000 cycles	15 years or 60 MWh throughput
Efficiency (published)	97.5% solar-to-grid (integrated inverter, 3 MPPT inputs)	Not published on enphase.com	90% round-trip, grid–battery–load

Sources: Tesla's Powerwall storage guide and Tesla Powerwall support; the Enphase IQ Battery 5P product page; and the FranklinWH aPower 2 datasheet (PDF).

Reading the table like an engineer

• Capacity (kWh) is how long the battery lasts — the size of the tank. A 15 kWh unit holds roughly three times the energy of a 5 kWh unit.
• Continuous power (kW) is how much load it can carry at once — the width of the pipe. This is what decides whether your air conditioner and well pump can run simultaneously during an outage.
• Peak power is the short burst the battery tolerates for motor starting surges (a few seconds to ten seconds). Motors like AC compressors draw several times their running wattage at startup — the 10-second peak rating is the number that matters for them.

What the manufacturers don't publish (and why it matters)

This is the part most comparisons skip. Each of these spec sheets has a conspicuous blank, and the blanks are not the same:

• Tesla does not publish a battery round-trip efficiency for the Powerwall 3. What it publishes instead is 97.5% "solar-to-grid" efficiency for the integrated inverter — a different measurement (inverter conversion, not the full charge-and-discharge cycle of the battery). It also publishes no throughput cap and no capacity-retention percentage terms in its warranty summary. That means you cannot compute the battery's lifetime guaranteed energy throughput from the public spec sheet alone.
• Enphase does not publish round-trip efficiency for the IQ Battery 5P on enphase.com. What it does publish is unusually concrete on the warranty side: 15 years, up to 6,000 cycles. A cycle bound is arguably more useful than an efficiency decimal — it caps how much cycling the warranty covers.
• FranklinWH publishes the most complete picture: 90% round-trip efficiency (grid–battery–load), plus a warranty defined as 15 years or 60 MWh of throughput, whichever comes first. The throughput figure lets you do honest lifetime math.

A missing number is not proof of a bad number — but it is proof you can't verify the claim, so don't let a salesperson fill the blank for them. If round-trip efficiency matters to your decision (it affects how much of your solar actually comes back out of the battery), ask the installer to put the figure in writing, with the measurement conditions stated.

The $/kWh math: the one calculation that cuts through quotes

Installers quote batteries as lump sums — one number for the whole job. To compare fairly, reduce every quote to dollars per usable kilowatt-hour:

Installed battery cost ÷ usable kWh = $/kWh (usable)

Two rules make this honest. First, use usable capacity, never nameplate — the table above already gives usable figures. Second, use the full installed cost (battery, electrical work, permits, commissioning), not the equipment-only price, because two quotes can hide very different labor in the lump sum.

Worked EXAMPLE (these are made-up numbers so you can see the method — replace every figure with your own quotes):

• EXAMPLE Quote A: one Powerwall 3 at $13,500 installed → $13,500 ÷ 13.5 kWh = $1,000/kWh usable.
• EXAMPLE Quote B: three IQ Battery 5P units (15 kWh total) at $18,000 installed → $18,000 ÷ 15 kWh = $1,200/kWh usable.
• EXAMPLE Quote C: one aPower 2 at $16,500 installed → $16,500 ÷ 15 kWh = $1,100/kWh usable.

In this example, Quote A wins on $/kWh — but the example is only step one. Two adjustments belong in step two: warranty length per dollar (a 15-year warranty spreads the same cost over 50% more years than a 10-year warranty, and the Enphase and FranklinWH warranties include explicit cycle/throughput bounds while Tesla's published terms do not), and peak power adequacy (the cheapest $/kWh is worthless if it can't start your AC — check the peak row of the table against your heaviest motor loads).

How to choose: the decision framework

There is no "best for everyone" here. Work through these four questions in order:

1. How much backup energy (kWh) do you actually need? This comes from your critical loads and how long an outage you want to ride through — not from your total electric bill. Our sizing guide walks through the kWh method step by step. Roughly: a few essential circuits for a half-day outage lands near one small unit; a full day of meaningful backup lands near 13–15 kWh, i.e., one Powerwall 3, one aPower 2, or three IQ 5P units.
2. What are your peak loads? List anything with a motor: central AC, well pump, sump pump. Compare the starting surge against the peak-power row and the running load against continuous power. If your AC's startup surge exceeds a unit's peak rating, you need more units in parallel or a different battery — no amount of capacity (kWh) fixes a power (kW) shortfall.
3. What equipment do you already have? Batteries pair most smoothly with their own manufacturer's ecosystem — one monitoring app, one warranty relationship, one company to call. If you already have Enphase microinverters, the IQ 5P is the natural fit; a Tesla or SolarEdge household should ask the installer specifically about integration, monitoring, and whether any additional gateway hardware is required. Get compatibility answers in writing before you commit.
4. Warranty length vs. throughput — which protects you more? A 10-year warranty on a battery you expect to cycle daily covers fewer lifetime kWh than a 15-year/6,000-cycle or 15-year/60-MWh warranty. If you plan heavy daily cycling (time-of-use arbitrage, frequent outages), throughput-defined warranties give you a number you can actually plan around. If you expect light backup-only use, the calendar years matter more.

The bottom line

On published specs alone: the aPower 2 offers the most storage per unit and the most transparent datasheet; the Powerwall 3 offers the highest continuous power per unit with the shortest published warranty; the IQ 5P offers the longest cycle-bounded warranty in the smallest building block, which makes it the most granular way to size a system (add 5 kWh at a time) at the cost of needing multiple units — and multiple units' worth of installation labor — to reach whole-home backup levels. Run the $/kWh math on your installed quotes, check peak power against your motors, and let those two calculations — not the brand on the box — make the decision.

Verified: 2026-10-11 — Powerwall 3: 13.5 kWh usable, 11.5 kW continuous (US), 10-year warranty, 97.5% solar-to-grid efficiency, no published round-trip efficiency or throughput/retention terms; IQ Battery 5P: 5.0 kWh usable, 3.84 kW continuous, 7.68 kW peak for 3 s / 6.14 kW for 10 s, 15-year / 6,000-cycle warranty, no round-trip efficiency published on enphase.com; aPower 2: 15 kWh AC usable, 10 kW continuous (11.5 kVA), 15 kW peak for 10 s, 15-year or 60 MWh throughput warranty, 90% round-trip efficiency (grid–battery–load), up to 15 units / 225 kWh per aGate. All linked sources opened and confirmed resolving on 2026-10-11.

This article was drafted with AI assistance and reviewed by the site editor.