The Home Battery ReportIndependent · No installer money

Savant Power Storage 20 vs FranklinWH aPower 2

A straight, side by side read on specs and warranties, with the honest caveats. Every figure is from the manufacturer datasheet; sources are at the bottom.

Figure - Specs to scalebars vs the largest in our database
Savant Power Storage 20 versus FranklinWH aPower 2: specs to scaleHorizontal bars comparing usable capacity, continuous power, peak power, warranty for Savant Power Storage 20 and FranklinWH aPower 2, each scaled against the largest value in the home battery database.Savant Power Storage 20FranklinWH aPower 2Usable capacity18 kWh15 kWhContinuous power12.5 kW10 kWPeak power30 kW15 kWWarranty10 yr15 yr
SpecSavant Power Storage 20FranklinWH aPower 2
ChemistryLiFePO4LFP
Usable capacity18 kWh15 kWh
Continuous power12.5 kW10 kW
Peak power30 kW15 kW
Round-trip efficiency93.8%90%
Warranty10 years, warrantied to 73 MWh or 3,650 cycles, with an estimated 75 percent capacity retention at 10 years15 years or 60 MWh throughput, whichever comes first
Backup scopeWhole-home capableWhole-home capable
InverterIntegratedIntegrated

What actually differs

  • More usable capacity: the Savant Power Storage 20 offers 18 kWh vs 15 kWh, so at that size it carries more of your home for longer per charge.
  • More continuous power: the Savant Power Storage 20 sustains 12.5 kW vs 10 kW, which matters for running big loads like an AC at once.
  • Longer warranty term: the FranklinWH aPower 2 is warranted 15 years vs 10, though always read the throughput or cycle cap too.
  • Different chemistry: the Savant Power Storage 20 is LiFePO4 and the FranklinWH aPower 2 is LFP. For a battery that never moves, LFP's safety and cycle life usually beat NMC's higher energy density.
  • Efficiency is not apples to apples here: the Savant Power Storage 20 quotes 93.8% (Round trip efficiency per the Savant Power Storage 20 specification sheet) and the FranklinWH aPower 2 quotes 90% (grid to battery to load (AC round trip)), so do not read the raw numbers as a direct ranking.

Which one pays off is a numbers question.

Neither spec sheet tells you the payback in your home. That comes from your rate plan and incentives.

Run the Worth It calculator →

Sources

Source: Savant Power Storage 20 Specification Sheet (009-2477-00). Specs verified 2026-07-01. Figures are per single unit at beginning of life; confirm the current datasheet with your installer.

Source: FranklinWH aPower 2 datasheet, Dec 2025. Specs verified 2026-07-01. Figures are per single unit at beginning of life; confirm the current datasheet with your installer.