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Home battery warranties compared: years, throughput and end-of-warranty capacity

Datasheets and warranty documents checked 8 Nov 2026.

Article by HomeSolarDexUpdated 8 Nov 2026

Data as of 8 Nov 2026, source: manufacturer PDFs listed under the table; IRS

Table of contents

Three numbers decide what a battery warranty is worth: the years, the capacity the maker promises at the end, and how much energy it lets you push through before the term runs out. Below they sit side by side for the 7 configurations in our battery table. Every figure comes from the manufacturer's own document, and a cell marked derived is our arithmetic (see methodology). To test what a battery can carry through an outage, use the battery runtime calculator.

Usable kWh and kWh promised at the end of the warrantyFrom each warranty document: the capacity percentage the maker promises at the end of the term, applied to usable kWh (our arithmetic). Not stated means the document gives no percentage.UsablePromised at endGenerac PWRcell 2, M6 cabinet (6 modules)18 kWh12.6 kWhFortress Power eBoost 1616 kWhnot statedFranklinWH aPower 215 kWh10.5 kWhTesla Powerwall 313.5 kWh9.45 kWhEnphase IQ Battery 10C10 kWh6 kWhGenerac PWRcell 2, M3 cabinet (3 modules)9 kWh6.3 kWhEnphase IQ Battery 5P5 kWh3 kWh
Usable kWh and kWh promised at the end of the warranty. From each warranty document: the capacity percentage the maker promises at the end of the term, applied to usable kWh (our arithmetic). Not stated means the document gives no percentage.
Warranty yearsTerm in years as printed in each warranty document. The throughput limit in MWh can end the warranty sooner, see the table.Enphase IQ Battery 5P15 yearsEnphase IQ Battery 10C15 yearsFranklinWH aPower 215 yearsTesla Powerwall 310 yearsGenerac PWRcell 2, M6 cabinet (6 modules)10 yearsGenerac PWRcell 2, M3 cabinet (3 modules)10 yearsFortress Power eBoost 1610 years
Warranty years. Term in years as printed in each warranty document. The throughput limit in MWh can end the warranty sooner, see the table.

The numbers

BatteryYearsUsable kWhPromised at endThroughput MWhCycle equiv.*
Tesla Powerwall 31013.570% (9.45 kWh*)37.82800*
Enphase IQ Battery 5P15560% (3 kWh*)30*6000*
Enphase IQ Battery 10C151060% (6 kWh*)60*6000*
FranklinWH aPower 2151570% (10.5 kWh*)604000*
Generac PWRcell 2, M6 cabinet (6 modules)101870% (12.6 kWh*)45.36*2520*
Generac PWRcell 2, M3 cabinet (3 modules)10970% (6.3 kWh*)22.68*2520*
Fortress Power eBoost 161016n/s128.6*8038*

* Derived by us. kWh at end is usable kWh times the promised percentage. Cycle equivalents are throughput divided by usable kWh. n/s: not stated. Tesla's 37.8 MWh applies only to uses outside solar self-consumption, time-based control and backup.

What stands out

  • The energy cap can run out before the years do. Generac caps each PWRcell 2 module at 7.56 MWh over 10 years, which is 2520 full cycles of a 3 kWh module (derived). At one full cycle a day that is about 6.9 years of daily use before the cap, and a full cycle every day for 10 years would be 3,650 cycles (derived).
  • The end-of-warranty promise differs by 10 points. Tesla, FranklinWH and Generac state 70%. Enphase states 60% for the IQ Battery 5P and 10C, with 6,000 cycles as the alternative end point.
  • Tesla ties throughput to how you use it. For solar self-consumption, time-of-use shifting and backup the warranty states unlimited cycles, with 70% at 10 years. Any other application, or a mix that includes one, brings a 37.8 MWh limit.
  • FranklinWH writes the throughput cap in MWh beside the years: not below 70% at 15 years or 60 MWh, whichever comes first. That is 4,000 cycles of 15 kWh (derived), under the 5,475 cycles that one cycle a day for 15 years would use (derived).
  • Fortress does not publish a retention figure for its 10 year warranty. The eBoost datasheet lists 8,000 cycles to a 70% end of life and a 10 year warranty, without linking the two.

Conditions that can shorten the term

Three of the documents cut the term if the battery is not connected or registered:

  • Tesla: at least four years are honored if the unit is offline for a long period or unregistered.
  • FranklinWH: a four year warranty applies to unregistered systems, and to systems offline for more than 90 consecutive days after a notice.
  • Generac: at least 5 years for the inverter, cabinet and switch, and at least 5 years or 3.78 MWh per module for the batteries, if the system stays offline.

Enphase's data sheets, as read, show the 15 year or 6,000 cycle term and the percentage, and do not state a shortened term for an offline unit. The full Enphase warranty text was not read for this page.

Why this matters in 2026

The IRS page for the Residential Clean Energy Credit states that the 30% credit applies to qualified property installed from 2022 through 31 December 2025, and that it is not available for property placed in service after that date. A battery installed today is outside that credit, so its price is not reduced by it. The dated wording is on the federal credit status page; programs that still pay toward a battery are in battery incentives.

None of the 7 documents publishes a price, so the table shows "not published" rather than an installer quote. Third party price figures, with their source, are in the home battery cost guide.

Not covered

SolarEdge Home Battery 400V is absent because its datasheet host returned HTTP 403 when we tried to read it on 8 Nov 2026. LG ESS Home is not listed because no current US datasheet was looked up. Capacity retention is a manufacturer promise at the end of the term, not a measured result. Portable units are on the power stations page and carry their own warranty column.

Documents read, 8 Nov 2026