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Powerwall vs Enphase vs FranklinWH: A California Battery Comparison (2026)

Short answer: there isn't one "best" home battery — the right pick depends on your solar setup and your goal (backup vs bill savings). In 2026 the three we're asked about most in Los Angeles are the Tesla Powerwall 3, the Enphase IQ Battery 5P and 10C, and the FranklinWH aPower 2. Below they are compared at matched storage capacity, with each manufacturer's own capacity definition named, and with the warranty limits worked out in years.

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Updated September 17, 2026 · Last fact-checked September 17, 2026 · By the Cali Energy team · Northridge, CA · CSLB #1032379 (B, C-10, C-39) — verify license

Powerwall vs Enphase vs FranklinWH: CA Battery Guide (2026)
Unlimited
Cycles allowed by Tesla's Powerwall warranty for solar self-consumption, time-based control and backup — the only warranty here with no use cap, though its 10-year term is the shortest
8.7–11.0 yr
When a FranklinWH aPower X and aPower 2 hit their throughput caps at one full cycle a day, against 12- and 15-year terms (Cali calculation)
48–185 A
Published motor-start rating (LRA) per unit across these batteries — a factor of nearly four
KEY TAKEAWAYS
  • Compare at matched storage, not per unit. One Powerwall 3 is 13.5 kWh; one IQ Battery 5P is 5.0 kWh. Three 5P units hold 15.0 kWh and deliver 11.52 kVA — the per-unit power gap closes once the capacities match.
  • Three published numbers decide the fit: capacity (kWh), continuous power (kW/kVA), and motor-start capability (LRA) — the surge that decides whether an air-conditioner compressor will actually start.
  • The longest warranty is not the strongest, and the makers do not set their checkpoints in the same places. Tesla and Enphase guarantee 70% of nameplate at year 10; Enphase then steps down to 60% at year 15, while FranklinWH sets no year-10 checkpoint and guarantees 70% at the finish. What ends the cover differs too: FranklinWH caps throughput at 60 MWh on the aPower 2, reached at about 11 years of a 15-year term at one full cycle a day, and at 43 MWh on the older aPower X, reached at about 8.7 years of a 12-year term. Tesla's 10 years is the only term here with no cap at all on solar self-consumption, load shifting and backup — though enrolling the battery in a virtual power plant moves it into a capped row. And it takes less cycling than people assume for a cap to start deciding: the FranklinWH caps overtake their terms at about 0.73 full cycles a day. The calculator below works it out at your own rate.
  • The 30% federal credit is gone for a battery placed in service in 2026, and as of 17 September 2026 every general-market SGIP residential storage step is closed — only one income-qualified branch is still open — so for most buyers the price gap between configurations is now paid in full.

First, the three numbers that decide the fit

Before brand names, three published specs decide whether a battery works in your home. They measure different things, and the first two get mixed up constantly.

Capacity (kWh) is the size of the tank — how much energy the battery stores. It sets how long you can run your loads. Continuous power (kW or kVA) is the size of the pipe — how much it can deliver at any one instant. It sets how much you can run at once. Motor-start capability (LRA) is the surge it can supply for the fraction of a second a compressor takes to spin up: a motor draws several times its running current at startup, so a battery that comfortably carries an air conditioner once it is running can still fail to start it.

Capacity numbers are not measured the same way, and the difference is specific. Tesla lists 13.5 kWh AC as nominal battery energy, measured at beginning of life, 25 °C and 3.3 kW. FranklinWH lists 15 kWh AC as usable system energy, on a new system at 25 °C and 3 kW. Enphase lists 5.0 and 10.0 kWh as usable capacity — and this is the one worth reading twice, because it does not mean what it sounds like. On the 5P datasheet total capacity and usable capacity are the same 5.0 kWh, and the footnote explains that the usable figure includes a 2% safety-critical reserve held back for a long outage, with a further 3% kept to run the battery’s own electronics overnight. So Enphase’s “usable” is the least conservative of the three labels, not the most. Read the definition next to the number, not just the number.

A big tank with a small pipe runs a fridge and lights for a long time but trips when the heat pump starts. A big pipe with a small tank starts heavy loads but drains fast. Per unit, the published start ratings on this page span 48 A to 185 A LRA — nearly a factor of four — which is why the start rating deserves its own line on a quote. Our home battery sizing calculator works through how many kWh your specific loads need.

The comparison table

Manufacturer-published specs for the current 2026 models, with each maker's own capacity wording kept intact — except the Best for column, which is our assessment and not the manufacturer’s. Specs and model names change; confirm against the latest datasheet for the exact model you are quoted.

Tesla Powerwall 3 vs Enphase IQ Battery 5P & 10C vs FranklinWH aPower 2 — published specs (2026)
BatteryEnergy, as publishedContinuous powerMotor startCouplingStackingBest for
Tesla Powerwall 313.5 kWh AC
nominal battery energy
11.5 kW AC on-grid
11,500 VA apparent; top of a 5.8–11.5 kW range; up to 15.4 kW off-grid, PV only — only at the 11.5 kW on-grid tier, with an 80 A breaker, from −20 to 25 °C
185 LRAIntegrated solar inverter, direct DC solar input up to 20 kW STCUp to 4 Powerwall 3 units for power, plus up to 3 Expansion units of 13.5 kWh each — 7 units maximumNew solar-plus-storage with strong whole-home backup in one unit
Enphase IQ Battery 5P5.0 kWh per unit
usable capacity
3.84 kVA per unit
7.68 kVA peak
Up to 48 A LRA
per unit
AC-coupled, grid-forming microinvertersModular; Enphase publishes branch-circuit limits (one unit per 20 A circuit) rather than a system maximumRetrofits and fine-grained sizing on existing solar
Enphase IQ Battery 10C10.0 kWh per unit
usable capacity; two 5.0 kWh units in one enclosure
7.08 kVA per unitUp to 90 A LRA
per unit
AC-coupled, four embedded grid-forming microinvertersModular; Enphase publishes a 40 A OCPD (8 AWG minimum) for one 10C and 80 A (4 AWG) for two or more, rather than a system maximumLarger backup on a microinverter system
FranklinWH aPower 215 kWh AC per unit
usable system energy
10 kW / 11.5 kVA
15 kW peak for 10 s, off-grid, at the 11.5 kVA tier
185 A LRAAC-coupled, paired with the aGate controllerUp to 15 units per aGate — 225 kWhLarge homes, heavy loads, generator integration

Enphase leads with kVA and Tesla and FranklinWH with kW; the figures above keep each maker's own unit, though the 10C sheet also gives 7.08 kW. FranklinWH's 10 kW and 185 A LRA apply only to the top 11.5 kVA rating, and that rating is a commissioned setting on the battery itself, not a different product: the aPower 2 datasheet lists four rated output tiers — 5, 7.6, 9.6 and 10 kW (5, 7.6, 9.6 and 11.5 kVA), with matching overcurrent devices of 30, 40, 50 and 60 A. The Powerwall 3 is configured exactly the same way, in four tiers from 5.8 to 11.5 kW; the tables here show the top tier for both. So two quotes can name the same battery and differ by more than half on power — ask which rated output tier the design is commissioned at and what breaker it lands on, not just the model name. Enphase and FranklinWH both specify lithium iron phosphate (LFP) cells; Tesla does not state cell chemistry in the Powerwall 3 datasheet. Efficiency is not comparable across these sheets either, and the numbers look misleadingly far apart: Tesla publishes 89% solar → battery → home and 97.5% solar → home on CEC-weighted methodology, FranklinWH 90% grid → battery → load, and Enphase 96% DC round-trip. Those measure different paths through the system. There is no published figure here that puts all three on one basis, so efficiency is not a spec you can rank these on from the datasheets.

Sources: Tesla Powerwall 3 datasheet · Enphase IQ Battery 5P datasheet · Enphase IQ Battery 10C datasheet · FranklinWH aPower 2 datasheet

The same comparison at matched storage

The table above lists one unit of each product, and the products are not sold in the same size. Lining up four ways to reach roughly the same storage changes the picture.

Four ways to reach roughly 13.5–15 kWh of home storage (2026)
ConfigurationStorage, as publishedContinuous powerMotor start
1 × Tesla Powerwall 313.5 kWh AC11.5 kVA
11.5 kW real
185 LRA
1 × FranklinWH aPower 215.0 kWh AC11.5 kVA
10 kW real
185 A LRA
3 × Enphase IQ Battery 5P15.0 kWh usable11.52 kVA48 A LRA per unit
1 × IQ Battery 10C + 1 × 5P15.0 kWh usable10.92 kVA90 and 48 A LRA per unit

Continuous power for the multi-unit Enphase rows is the sum of the per-unit ratings Enphase publishes. Motor-start capability is published per unit only, so a design that has to start a specific compressor should be confirmed against the combined start rating for that exact configuration.

At matched storage the power gap all but disappears. Every one of these products publishes an apparent-power rating, and on that common basis the four configurations are 11.5, 11.5, 11.52 and 10.92 kVA — the same number four times over. What stays different is the shape of the decision — one large box against three smaller ones, wall space and cost per step, whether the units bolt onto the solar you already own, the published start rating, and the warranty. Those are the grounds to choose on, not a per-unit kWh figure.

AC-coupled vs DC-coupled: why it matters for your setup

This is the spec that most often decides which battery is a natural fit — and it depends on what solar you already have.

Solar panels produce DC power; your home uses AC. A DC-coupled approach captures panel energy on the DC side before it is converted, which is efficient and tidy for a new solar-plus-storage install. The Powerwall 3 fits here: it integrates a solar inverter and takes direct DC solar input up to 20 kW STC across six MPPTs, so one box handles inverting and storage. An AC-coupled battery (Enphase IQ, FranklinWH aPower 2) has its own inverter and connects on the AC side, which makes it straightforward to add onto an existing solar system without replacing your current inverter or microinverters.

Neither approach is universally better. If you already run Enphase microinverters, an Enphase battery is the most seamless match. If you are installing fresh solar and want backup in one unit, a Powerwall 3 with direct DC solar input can simplify the design. FranklinWH's AC-coupled aGate is built to orchestrate solar, battery, grid and a backup generator together, which suits larger or more complex homes. The right answer falls out of your existing equipment, not a brand ranking.

Warranties: the year on the cover is not the promise

Every one of these warranties combines three separate limits — a term in years, a cap on how much you may use the battery, and a floor under how much capacity it must still hold. Whichever limit arrives first ends the cover.

What each warranty guarantees, and when its use cap arrives (2026)
BatteryTermCap on useCapacity guaranteedCap reached at one full cycle a day
Tesla Powerwall 3
13.5 kWh
10 yearsNone — unlimited cycles for solar self-consumption, time-based control and backup. Any other application, or any combination that includes an application other than those three, is capped at 37.8 MWh of aggregate throughput measured at the battery AC output — enrolling in a virtual power plant or a demand-response programme is the usual way a California home lands in that row70% of 13.5 kWh at year 10Never on those three uses
7.7 yr if the 37.8 MWh cap applies
Enphase IQ Battery 5P
5.0 kWh
15 years6,000 discharged cycles70% at year 10, then 60% at the end
on the current warranty; units activated under the superseded edition have a flat 60% floor
16.4 yr — the term ends first
Enphase IQ Battery 10C
10.0 kWh
15 years6,000 discharged cycles70% at year 10, then 60% at the end
on the current warranty; units activated under the superseded edition have a flat 60% floor
16.4 yr — the term ends first
FranklinWH aPower 2
15 kWh
15 years60 MWh aggregate throughputAt least 70% of 15 kWh11.0 yr — the cap ends the cover first
FranklinWH aPower X
13.6 kWh, 5 kW — the previous generation (SKU APR-05K13V1/V2-US), still quoted
12 years43 MWh aggregate throughputAt least 70% of 13.6 kWh8.7 yr — the earliest cap on this page

The last column is a Cali Energy calculation from each manufacturer's own two published limits: 6,000 ÷ 365 = 16.4 years; 60 MWh ÷ 15 kWh = 4,000 full cycles, ÷ 365 = 11.0 years; 43 MWh ÷ 13.6 kWh = 3,162 cycles, ÷ 365 = 8.7 years; 37.8 MWh ÷ 13.5 kWh = 2,800 cycles, ÷ 365 = 7.7 years. It assumes one full nameplate cycle every day, and the two kinds of cap move differently from there. Capacity fade pushes the megawatt-hour caps later, because an ageing battery delivers less energy per cycle. It does nothing to Enphase’s cycle cap, which counts discharges rather than energy — and since Enphase does not define how a partial discharge counts, a home that discharges twice a day could reach 6,000 cycles in about eight years rather than sixteen, in which case the cap ends the cover before the term does. A household that cycles once a day or less never approaches a megawatt-hour cap. Sources: Tesla Powerwall limited warranty (USA) · Enphase IQ Battery 5P warranty (US/Canada, effective 27 December 2024) · Enphase storage warranty (10C) · FranklinWH limited warranty

Work it out for your own house

The table above is fixed at one full cycle a day. That is a convenient assumption, not your house — and the conclusion changes inside the ordinary range. Move the sliders to see which limit actually ends each warranty at the rate you will really use the battery.

When does each warranty actually run out?

Two sliders, because the manufacturers cap two different things. Tesla and FranklinWH cap energy in megawatt-hours, so a half-depth cycle spends half a cycle’s worth. Enphase caps discharges, and depth does not count — two shallow discharges a day spend the allowance twice as fast as one deep one.

Live: when each warranty ends at the usage rate you set — term against use cap, calculated from each manufacturer’s two published limits
BatteryTermUse cap reachedWhat ends the cover
Tesla Powerwall 3
solar self-consumption, load shifting, backup
10 yr
no cap
 
Tesla Powerwall 3
in a VPP, or any other application
10 yr  
Enphase IQ Battery 5P / 10C
6,000 discharged cycles
15 yr  
FranklinWH aPower 2
60 MWh throughput
15 yr  
FranklinWH aPower X
43 MWh throughput, previous generation
12 yr  
 

Cap years are each manufacturer’s own two published limits divided by the rate you set: 2,800 cycles for Tesla’s 37.8 MWh at 13.5 kWh, 6,000 discharges for Enphase, 4,000 cycles for FranklinWH’s 60 MWh at 15 kWh, 3,162 for 43 MWh at 13.6 kWh. A warranty ends when the term or the cap arrives, whichever is first. Capacity fade pushes the megawatt-hour caps later in real life and does not move a discharge count. Enphase does not define how a partial discharge counts toward one, so its row is the least certain on this page — ask before you sign.

Three things fall out of that table. First, the documents do not even set their checkpoints in the same places, so “70%” is not one promise repeated. Tesla and Enphase both fix a floor at year 10 — 70% of nameplate. Enphase then runs five more years on the calendar with the floor stepping down to 60% at year 15. FranklinWH sets no year-10 checkpoint at all: its single guarantee is 70% at whichever comes first, the end of the term or the throughput cap. That is a stronger floor at the finish and no stated promise in between. Second, a cap can end a warranty years before its term does — a household that fully cycles an aPower 2 every day, which is exactly what NEM 3.0 arbitrage asks of it, reaches the 60 MWh limit at about eleven years, not fifteen. Third, the shortest headline warranty here is the only one with no cap at all on the three uses a California solar home actually has.

The caps are also written in different currencies. Tesla and FranklinWH cap megawatt-hours, which is unambiguous. Enphase caps discharged cycles, and the warranty does not define how a partial discharge counts toward one — worth asking before you sign. Beyond that, ask whether labor and the inverter are covered, and who honors the claim, the manufacturer or your installer. A warranty is only as good as the company standing behind it a decade from now.

Backup vs bill savings: match the battery to your goal

Before comparing brands, get clear on why you want a battery. The two common goals pull toward different specs.

Whole-home backup

If riding out a PSPS shutoff or outage is the priority, you need enough capacity to last the night, enough continuous power to carry the loads, and enough start capability to get the compressor turning in the first place.

Bill savings under NEM 3.0

On NEM 3.0 (SCE/PG&E/SDG&E), exports earn a time-varying credit usually far below retail. A battery lets you store midday solar and use it at night instead of exporting cheap and buying back expensive. This is the use that cycles the battery hardest, so check the warranty cap as well as the capacity.

LADWP homes

LADWP is municipal and is not on NEM 3.0, so the bill-savings case for a battery is usually weaker there — confirm your current net-metering terms with LADWP before sizing a battery for savings rather than backup — many LADWP customers add a battery mainly for backup. Lighter cycling also keeps a throughput cap far away.

Partial vs whole-home

You do not have to back up everything. Backing up a few critical circuits needs less battery than whole-home backup with the AC running — and costs less.

Existing equipment

Your current inverter or microinverters often point to the natural battery choice (AC- vs DC-coupled). Retrofits favor AC-coupled units.

Room to grow

The ceilings differ and so does the step size. Tesla adds 13.5 kWh Expansion units, up to three behind a Powerwall 3 and seven units in total; FranklinWH scales to 15 units per aGate; Enphase grows in 5.0 kWh steps, the smallest increment of the three.

WHAT A BATTERY COSTS YOU IN 2026

The federal credit has ended, and the main SGIP step is closed

The 30% federal Residential Clean Energy Credit (Section 25D) is not available for any property placed in service after December 31, 2025, so a battery installed in 2026 and owned by the homeowner earns no federal residential credit. Our guide to the credit's end covers what carried forward and what did not.

California's Self-Generation Incentive Program continues, but not evenly. The program runs as ten budget categories, each with its own status in each utility territory, and checking one tells you nothing about another. Checked on 17 September 2026, every general-market residential storage step is closed — small residential storage at $0.15/Wh and Equity Resiliency at $1.00/Wh, in all four investor-owned territories. The income-qualified Residential Solar and Storage Equity tiers at $1.10/Wh are mostly waitlisted, including the branch LADWP administers, with one exception: the AB 209 POU branch, administered in the SCE and PG&E territories, shows Open. So a rebate is not impossible in 2026 — it is narrow, income-qualified, and it depends which category and which territory you fall under. Statuses move week to week, so read the step tracker for your own category and do not put a rebate into your project economics until eligibility and a reservation are confirmed in writing.

This changes one thing about the choice. While the credit ran, buying extra capacity up front was 30% subsidized, which favored the larger box on day one. In 2026 every additional kilowatt-hour is paid in full, which makes buying what you need now and expanding later a more even-handed option than it was in 2025.

So which one should you get?

Honestly: it depends, and any installer who names a "best battery" before seeing your roof and your goals is skipping steps. The specs point at fairly clear defaults. A Powerwall 3 pairs cleanly with new solar, puts an inverter and 185 LRA of start capability in one DC-coupled box, and carries the only warranty here with no cycle cap on ordinary household use. The Enphase IQ line shines on existing microinverter systems and where you want to size storage in 5 kWh steps, at the cost of the lowest start rating per unit — a figure Enphase publishes only per unit, so a design that has to start a specific compressor needs the combined rating for that exact configuration confirmed — and the weakest end-of-term capacity floor. The FranklinWH aPower 2 holds the most energy per box, matches Tesla on start capability, integrates a generator, and guarantees 70% at the end — provided daily cycling has not reached its throughput cap first.

The deciding factors are your existing equipment, your backup versus savings priority, how hard you will cycle it, and your budget — not brand loyalty. We install all three, so we will size and quote whichever genuinely fits your home.

Want to work out the numbers for your house first? Start with the battery sizing calculator, then talk to us at +1-323-844-7777.

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Frequently asked

Which is the best home battery in California in 2026?

There is no single best battery — the right pick depends on your solar setup and your goal. Compared at matched storage, the four options are closer than their per-unit specs suggest: one Tesla Powerwall 3 is 13.5 kWh AC and 11.5 kVA; one FranklinWH aPower 2 is 15 kWh AC and 11.5 kVA; three Enphase IQ Battery 5P units are 15.0 kWh usable and 11.52 kVA; and one IQ Battery 10C plus one 5P is 15.0 kWh usable and 10.92 kVA. The real separators are coupling (Powerwall 3 is DC-coupled with an integrated solar inverter; Enphase and FranklinWH are AC-coupled and retrofit easily), published motor-start capability (185 LRA for Tesla and FranklinWH, up to 90 and 48 A LRA per Enphase unit), and the warranty limits.

Which home battery warranty has no cycle or throughput limit?

Tesla's. The Powerwall limited warranty (Rev. 2.6) covers the Powerwall 3 for 10 years at 70% of its 13.5 kWh rated capacity with unlimited cycles, provided the battery is used for solar self-consumption, time-based control or backup — between them, ordinary California household use. The 37.8 MWh throughput cap applies when the battery is used for some other application, or for a combination that includes an application other than those three; enrolling in a virtual power plant or a demand-response programme is the common way a California home ends up there, and at that point the cap works out to roughly 7.7 years at a full cycle a day. By contrast Enphase caps the IQ Battery 5P and 10C at 6,000 discharged cycles inside a 15-year term, and FranklinWH caps aggregate throughput at 60 MWh on the aPower 2 inside 15 years and 43 MWh on the older aPower X inside 12 years. Whichever limit arrives first ends the cover.

Does a 15-year battery warranty really last 15 years?

Not necessarily — the use cap can arrive years first, and which product you are quoted decides how early. FranklinWH warrants the aPower 2 for 15 years or 60 MWh of throughput; at 15 kWh per full cycle that is 4,000 cycles, so a home that fully cycles it daily reaches the cap at about 11 years. The previous-generation aPower X is warranted for 12 years or 43 MWh, which at 13.6 kWh per cycle is 3,162 cycles — about 8.7 years, the earliest cap of any product compared here. Enphase caps discharged cycles rather than energy, which behaves differently: at one discharge a day 6,000 cycles is about 16.4 years and the 15-year term ends first, but at two discharges a day it is about 8.2 years and the cap ends first — and Enphase does not define how a partial discharge counts toward one, so ask. Capacity fade pushes the megawatt-hour caps later, because an older battery moves less energy per cycle; it does not push a cycle cap later. The arithmetic is ours; the two limits in each line are the manufacturer's own.

What capacity is guaranteed at the end of the warranty?

The three makers do not put their checkpoints in the same places, so the honest answer has to name the date as well as the percentage. Tesla guarantees 70% of 13.5 kWh at year 10, where its term ends. Enphase guarantees 70% at the end of the tenth year and 60% at the end of the fifteenth, for both the IQ Battery 5P and the 10C — but that two-step structure comes from the warranty effective 27 December 2024; a unit activated under the superseded edition carries a flat 60% floor with no year-10 step, so the activation date matters. FranklinWH sets no year-10 checkpoint at all: it guarantees at least 70% of rated capacity at whichever comes first, the end of the term or the throughput cap — 15 years or 60 MWh on the aPower 2, 12 years or 43 MWh on the aPower X. So the longest calendar term carries the lowest end-of-term floor, and the strongest floor at the finish comes with no promise in between.

What is the difference between usable capacity, continuous power and motor start?

Capacity (kWh) is how much energy the battery stores — it sets how long you can run your loads. Continuous power (kW or kVA) is how much it can deliver at once — how many things run simultaneously. Motor-start capability (LRA) is the brief surge available when a compressor spins up, which draws several times its running current; a battery can carry an air conditioner and still fail to start it. All three are on the datasheets — but the capacity labels are not equivalent. Tesla publishes 13.5 kWh as nominal battery energy at 3.3 kW and 25 °C; FranklinWH publishes 15 kWh as usable system energy at 3 kW; Enphase publishes 5.0 and 10.0 kWh as usable capacity, which on its own datasheet is the same number as total capacity, with a 2% safety reserve and a further 3% for overnight electronics taken out of it rather than before it.

What does AC-coupled vs DC-coupled mean for a battery?

A DC-coupled approach captures panel energy on the DC side and is efficient for a new solar-plus-storage install. The Powerwall 3 integrates a solar inverter and takes direct DC solar input up to 20 kW STC. An AC-coupled battery (Enphase IQ, FranklinWH aPower 2) has its own inverter and connects on the AC side, which makes it easy to add onto an existing solar system without replacing your current inverter. Your existing equipment usually points to the natural choice.

Is there still a rebate or tax credit for a home battery in 2026?

No federal one for a homeowner-owned system: the 30% federal Residential Clean Energy Credit (Section 25D) is not available for property placed in service after December 31, 2025. California's SGIP still runs, as ten budget categories each with its own status per utility territory. Checked on 17 September 2026, every general-market residential storage step is closed — small residential storage at $0.15/Wh and Equity Resiliency at $1.00/Wh, across all four investor-owned territories. The income-qualified Residential Solar and Storage Equity tiers at $1.10/Wh are mostly waitlisted, including the branch LADWP administers, with one exception: the AB 209 POU branch, administered in the SCE and PG&E territories, shows Open. So a rebate is narrow rather than gone — it is income-qualified and depends on your category and territory. Statuses move week to week, so check the step tracker for your own category and do not count a rebate until eligibility and a reservation are confirmed in writing. See our SGIP guide.

Do I need backup for my whole home or just some circuits?

Either works — and partial backup costs less. Backing up a few critical circuits (fridge, lights, internet, a few outlets) needs far less battery than whole-home backup with the air conditioner running. Decide which loads you truly need during an outage, then size capacity, continuous power and start capability to match. Our sizing calculator helps estimate the kWh you need.

At what point does a battery warranty's use cap start mattering more than its term?

Earlier than most people assume — below one full cycle a day for the FranklinWH products. Dividing each manufacturer's cap by its term: the aPower X cap overtakes its 12-year term at about 0.72 full cycles a day, the aPower 2 at about 0.73, and the capped Tesla row (a virtual power plant or any use outside solar self-consumption, load shifting and backup) at about 0.77. Enphase is the outlier because it counts discharges rather than energy: its 6,000-cycle cap overtakes the 15-year term at about 1.1 discharges a day, so a household that discharges twice daily reaches it at roughly 8.2 years. Below those rates the calendar ends the warranty; above them the cap does. The calculator on this page works it out at whatever rate you expect to use.

Related reading

Sources & methodology

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Prepared by Cali Energy, September 17, 2026. This article is for general educational purposes only and is not legal, tax, financial, engineering, or utility advice. Rates, incentives, codes, permit requirements, equipment specifications, prices, and program terms may change; figures and timelines are estimates, not guarantees. Confirm current requirements with the applicable utility, AHJ, program administrator, manufacturer, or a licensed professional. See our Content Disclaimer. Cali Energy · 19201 Parthenia St, Unit E, Northridge, CA 91324 · CSLB #1032379 (B, C-10, C-39)