Home Battery Warranty Guide: What Each Brand Actually Covers
How Tesla, Enphase, FranklinWH, Generac, SolarEdge, Panasonic, and sonnen warranty terms compare, what can void coverage, and what happens if your installer goes out of business.
Shortlist
Quick answer: A home battery warranty is really three limits stacked together: years, a cycle or throughput cap, and an end-of-warranty capacity guarantee, usually 60 to 70 percent. Tesla Powerwall 3 covers 10 years at 70 percent capacity. Enphase IQ Battery 5P and FranklinWH aPower 2 both publish 15-year terms, but Enphase caps at 6,000 cycles with roughly 60 percent capacity, and FranklinWH caps at 60 MWh of throughput and cuts unregistered systems down to 4 years. Read the cycle cap and the registration and connectivity conditions before comparing years.
Best for
Homeowners comparing home battery warranty terms across brands and installer quotes in US.
Wrong fit
Off-grid cabins, RV systems, marine systems, or commercial storage projects.
Tradeoff
A longer published warranty term is only as good as its cycle or throughput cap, its capacity-retention floor, and whether registration or an internet connection is required to keep it.
A home battery warranty is really three limits stacked together: years, a cycle or throughput cap, and an end-of-warranty capacity guarantee, usually 60 to 70 percent. Tesla Powerwall 3 covers 10 years at 70 percent capacity. Enphase IQ Battery 5P and FranklinWH aPower 2 both publish 15-year terms, but Enphase caps at 6,000 cycles with roughly 60 percent capacity, and FranklinWH caps at 60 MWh of throughput and cuts unregistered systems down to 4 years. Read the cycle cap and the registration and connectivity conditions before comparing years.
Most installer proposals lead with the number of years. That number alone tells you almost nothing about what you actually get back if the battery degrades early or fails. Two "15-year" warranties can mean very different things once cycle limits, capacity floors, and registration paperwork enter the picture.
The three numbers that make up a warranty
Term length. The number of years from activation, but almost every manufacturer also caps coverage by cycles or total energy throughput, whichever comes first. A battery cycled hard every day can hit its throughput cap years before the stated term ends.
Capacity retention. The minimum percentage of original usable capacity the manufacturer guarantees at the end of the warranty, commonly 60 to 70 percent. This is the number that tells you how much runtime you keep, not the year count.
Conditions. Registration at installation, staying on a certified installer's paperwork, and in several cases keeping the system connected to the internet for firmware updates. Miss one of these and the warranty can shrink dramatically, sometimes to a fraction of the published term.
How the major brands compare
Terms below are drawn from each manufacturer's published warranty documentation and product pages, current as of the dates shown. Confirm the exact document for your model and activation date with your installer before signing, since manufacturers revise warranty documents over time.
Brand and model
Term
Cycle or throughput cap
End-of-warranty capacity
Registration or connectivity condition
As of
Tesla Powerwall 3
10 years
Unlimited cycles for solar self-consumption, time-based control, and backup use
70%
Requires the system to stay internet-connected for firmware updates
2026-07
Enphase IQ Battery 5P
15 years
6,000 cycles, whichever comes first
About 60% per EnergySage's equipment data
Claims flow through Enphase-certified installers; older gen2 IQ Batteries carry a shorter 10-year term
2026-07
FranklinWH aPower 2
15 years
60 MWh throughput per unit, whichever comes first
Not stated as a fixed percentage in the current end-user warranty document
Registration required at installation; unregistered systems drop to 4 years, and FranklinWH's own warranty explainer notes that losing internet connectivity can also reduce the covered period
2026-08
Generac PWRcell 2
10 years parts, labor, and limited travel on the cabinet, inverter, and Smart Disconnect Switch
Battery modules: 10 years or 7.56 MWh throughput per module, whichever comes first
70% (modules)
Must be registered and internet-connected, or coverage can drop to 5 years; only Generac-certified technicians can perform covered repairs
2026-07
SolarEdge Home Battery
10 years
Unlimited cycles and throughput
70%
Claims route through your installer and SolarEdge's support queue
2026-07
Panasonic EVERVOLT
12 years workmanship and performance
6,000-cycle-equivalent throughput at 90% depth of discharge
70% (EV-B5 battery)
Panasonic exited the residential energy storage business in April 2025 and stated it would continue to honor existing warranties and support
2026-07
sonnenCore+
120 months (10 years)
10,000 cycles, whichever comes first
Not less than 70%
Requires installation by a sonnen-certified installer plus product registration
2026-07
Panasonic's exit is worth sitting with: a manufacturer can stop selling a product line and still owe you 12 years of coverage. That promise is only as strong as the company backing it, which is exactly why the next section matters as much as the table above.
What can actually void a home battery warranty
Installing outside the certified network. Tesla, FranklinWH, Generac, and sonnen all route warranty service through certified installers. A system installed or later serviced by someone outside that network can jeopardize coverage.
Skipping registration. FranklinWH cuts an unregistered aPower 2 down to 4 years from 15. Generac requires registration plus an internet connection or coverage can drop to 5 years. Sonnen requires registration outright. Ask your installer to show you the registration confirmation, not just tell you it happened.
Losing internet connectivity. Tesla's warranty terms require the system to stay connected for firmware updates. FranklinWH's own warranty explainer says a loss of connectivity can also reduce the covered period, even on a registered system. If your home has spotty internet or you plan to disable the app connection, ask specifically how that affects coverage.
Unauthorized modifications. Adding components, batteries, or inverters the manufacturer has not approved, or exceeding the system's rated continuous power on a regular basis, can void coverage industry-wide. Get any expansion or add-on in writing as manufacturer-approved before it goes in.
None of this is unusual or predatory. It is standard equipment-warranty practice. The problem is that installers rarely walk buyers through it before signing, so it becomes a surprise only when something breaks.
What happens if your installer goes out of business
A home battery quote actually carries two separate warranties, and they do not fail together.
The workmanship warranty, covering the installer's labor and wiring, is tied to that specific company. If the installer closes, that coverage is effectively gone, since there is no longer anyone contractually on the hook for it.
The manufacturer's product warranty, covering the battery hardware itself, is a separate contract with the manufacturer and can survive an installer's closure, as long as the manufacturer is still operating and you have your registration and purchase documentation. The risk case is both companies failing at once: if the manufacturer also exits the business or goes bankrupt, you can be left with no one to honor either warranty.
Before signing, ask your installer directly: if you close, who services my system under manufacturer warranty, and do I need anything from you today, in writing, to make that claim later? Keep your registration confirmation, activation date, and purchase agreement in your own records rather than trusting a portal you may lose access to if the installer disappears.
This is the same pattern buyers should already be watching for on the financing side. The home battery financing guide covers Solar Mosaic's 2025 bankruptcy and emergence under a new servicer, which is a useful reminder that a company failure does not have to mean you lose everything, but it does mean you need your own paperwork.
Quote red flags
The proposal states a warranty length but not the cycle or throughput cap, or the end-of-warranty capacity percentage.
No one can tell you whether the system will be registered, or when.
The installer cannot explain what happens to your warranty if they close, or waves off the question.
A verbal promise of a "lifetime" or unusually long warranty that is not in the written manufacturer documentation.
The quote bundles an extended installer warranty without stating what it actually adds beyond the manufacturer's coverage, or what happens to that add-on if the installer closes.
What to ask before signing
What are the exact term, cycle or throughput cap, and end-of-warranty capacity percentage, from the current manufacturer document, not a sales sheet summary?
Will the system be registered at installation, and can I see confirmation once it happens?
Does the warranty require ongoing internet connectivity, and what happens if that connection drops?
If you go out of business, who do I contact for a manufacturer warranty claim?
Does anything about my planned use, such as VPP participation or heavy daily cycling, affect the warranty terms?
If you already have a written proposal in hand and want a second read on the whole quote, not just the warranty line, see how to read a battery quote or start a quote review.
Where this fits in your shortlist
Warranty terms are one input, not the whole decision. If you are still comparing brands broadly, start with the best home batteries shortlist. If your shortlist has narrowed to the three most commonly quoted whole-home systems, the full Powerwall 3 vs Enphase vs FranklinWH comparison covers capacity, power, and installed cost alongside warranty.
Commercial note
Home Battery Guide may earn from affiliate links or flat-fee referrals to named vetted installers. Rankings do not move with compensation. We do not sell the same lead to multiple installers, and a referred installer quote still has to pass the same quote check.
Frequently Asked Questions
Is a longer warranty always better?
Not by itself. A 15-year warranty capped at 6,000 cycles with 60 percent end-of-warranty capacity is not automatically better than a 10-year warranty with unlimited cycles and 70 percent capacity. Compare all three numbers together, not just the year count.
Do I have to register my home battery for the warranty to count?
Often yes, and the penalty for skipping it can be severe. FranklinWH drops an unregistered aPower 2 from 15 years to 4. Generac requires registration and an internet connection or coverage can fall to 5 years. Confirm registration happened rather than assuming your installer handled it.
Does my home battery warranty require internet access?
For several brands, yes, at least in part. Tesla's warranty terms require the system to stay connected for firmware updates, and FranklinWH's own warranty materials note that losing connectivity can reduce coverage even on a registered system. Ask specifically how your household's internet reliability interacts with this.
What happens to my warranty if my installer goes out of business?
The installer's own workmanship warranty on labor and wiring is generally void once they close. The manufacturer's product warranty on the battery hardware can still apply if the manufacturer is still operating, provided you have your registration and purchase records. If the manufacturer also fails, warranty protection can disappear entirely, which is why keeping your own documentation matters more than trusting an installer's portal.
Does a battery's warranty transfer if I sell my house?
Transferability varies by manufacturer and is not something this guide can verify universally. Ask your installer for the specific transfer process in writing, and confirm it with the manufacturer's current warranty document rather than a verbal answer, before you rely on it in a home sale.
These guides are built from public specifications, primary program pages, utility documentation, manufacturer materials, and repeated buyer questions that show up in quote and installation decisions.
Manufacturer and installer responses can clarify pricing bands, warranty terms, support footprint, and common mistakes. They do not move a page up the shortlist on their own.
