review.solar · Sourced values document
eVault MAX 18.5
18.43 kWh · LFP · DC-coupled
Fortress Power
Performance & Value
Released 2021 · Evidence checked 2026-08-05 · Scored to Solar Analytica battery rubric v2.9.0
70/100
Very good
Overall
Score by category
Capacity & Usability
90
Power & Efficiency
82
Longevity (verified)
62
Safety & Chemistry
66
Guarantee & Backbone
64
Energy Ecosystem
62
Sourced specification values
Published capacity range18.43 kWh
Scored configuration18.43 kWh
Cell chemistryLFP (LiFePO4)
Usable energy / DoD100% DoD
Continuous power output9.2 kW
Round-trip efficiency98%
Cycle life8000 cycles
Warranty period10 yr
Safety certificationUL9540 / IEC62619
Reliability testingNot independently tested
Manufacturing track record10-15 years

Some values are estimated where independent verification was not available: see the full scorecard and review.solar/terms.

Page 2 · Audit sheet: complete sourced record (1 of 2)

eVault MAX 18.5 · every criterion scored by the live rubric (Solar Analytica battery rubric v2.9.0), with its recorded value, evidence status, and any linked source. Page 1 carries the buying-decision summary; this and the next page are the full record for verification and right of reply.

Capacity & Usability
Usable energy / DoD (%)100datasheetSource
Modularity & scalabilityFully modular / stackable expandabledatasheetSource
Energy density / footprintAveragestatedSource
Battery generation compatibilitySame-generation expansion only: matching spec modules required; clean path butdatasheetSource +1
Power & Efficiency
Round-trip efficiency (%)98datasheetSource
Continuous power output (kW)9.2datasheetSource
Backup switching speed>100ms or switching speed not discloseddatasheetSource
Operating temperature rangeStandarddatasheetSource
Longevity (verified)
Cycle life (cycles to 70%)8000datasheetSource
Warranty throughput2.5-5 MWh warranted per kWh usabledatasheetSource +1
Warranty period (yrs)10datasheetSource +1
End-of-warranty retained capacity (%)0reviewed absenceSource
Verified reliabilityNot independently testedreviewed absenceSource
Cell balancing architecturePack-level only / not disclosedreviewed absenceSource
Warranty degradation guaranteeWarranty degradation terms not specifieddatasheetSource +1

review.solar · audit sheet · Solar Analytica battery rubric v2.9.0 · https://review.solar/cards/fortress-power-evault-max-18-5-us

Page 3 · Audit sheet: complete sourced record (2 of 2)

eVault MAX 18.5 · continued from page 2 · Solar Analytica rubric Solar Analytica battery rubric v2.9.0.

Safety & Chemistry
Cell chemistryLFP (LiFePO4)datasheetSource
Safety certificationUL9540 / IEC62619datasheetSource
Thermal & fire mitigationBasicdatasheetSource
AC terminal & connection protectionNot specifiedreviewed absenceSource
Ingress protection (outdoor)Indoor onlydatasheetSource +1
Guarantee & Backbone
Warranty assuranceParts onlydatasheetSource +1
Financial strength & warranty backingStable / listedsecondarySource
Manufacturing track record10-15 yearsdatasheetSource +1
Energy Ecosystem
Grid-forming & backup tierWhole-home backup via paired hybrid inverter (capability is inverter-dependentdatasheetSource +1
Open protocol & API maturityModbus TCP + cloud APIdatasheetSource +1
VPP & grid services readinessVPP-capable + live VPP program (named market)datasheetSource +1
EV charging integrationNo EV integrationreviewed absenceSource
Thermal load managementSmart relay switching (excess solar triggered)datasheetSource +1
Smart home & IoT depthCommunity integration (Home Assistant, no native support)secondarySource
Dual-port flexibilitySingle multi-function port: third-party sync or backup, software-configurable datasheetSource +1

review.solar · audit sheet · Solar Analytica battery rubric v2.9.0 · https://review.solar/cards/fortress-power-evault-max-18-5-us