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This figure is printed on the California Energy Commission Solar Equipment List (data unchanged since October 1, 2026) as submitted for the listing. No maker document in the catalog prints it for this model yet.
Listed as "Lithium Iron Phosphate" under "Technology" on the California Energy Commission list (data unchanged since October 1, 2026; downloaded October 11, 2026).
Issuer record: CEC Battery List, official spreadsheet (data unchanged since October 1, 2026; downloaded October 11, 2026) October 1, 2026 · Checked · Earlier documentLocation: Row 180, Technology
Documented
This figure is printed on the California Energy Commission Solar Equipment List (data unchanged since October 1, 2026) as submitted for the listing. No maker document in the catalog prints it for this model yet.
Listed as "20.48" under "Nameplate Energy Capacity (kWh)" on the California Energy Commission list (data unchanged since October 1, 2026; downloaded October 11, 2026).
Issuer record: CEC Battery List, official spreadsheet (data unchanged since October 1, 2026; downloaded October 11, 2026) October 1, 2026 · Checked · Earlier documentLocation: Row 180, Nameplate Energy Capacity (kWh)
Documented
Printed Nominal Voltage for the complete DC ESS in a maker-hosted SGS certificate copy, effective 08 April 2026. This records technical data, not independent directory verification.
Official certificate: Fortress Power eSpire Nano outdoor DC ESS SGS certificate of compliance to ANSI/CAN/UL 9540:2023 (maker-hosted copy, SGSNA/26/SZ/00141) Rev Effective 08 April 2026 · Checked · Earlier documentLocation: PDF page 2, printed Page 2 of 3, Technical Data table, FP-Nano-S4-O column
Documented
This figure is printed on the California Energy Commission Solar Equipment List (data unchanged since October 1, 2026) as submitted for the listing. No maker document in the catalog prints it for this model yet.
Listed as "20.48" under "Maximum Continuous Discharge Rate (kW)" on the California Energy Commission list (data unchanged since October 1, 2026; downloaded October 11, 2026).
Issuer record: CEC Battery List, official spreadsheet (data unchanged since October 1, 2026; downloaded October 11, 2026) October 1, 2026 · Checked · Earlier documentLocation: Row 180, Maximum Continuous Discharge Rate (kW)
Documented
Printed Operating Voltage Range for this exact outdoor DC ESS. No series calculation.
Official certificate: Fortress Power eSpire Nano outdoor DC ESS SGS certificate of compliance to ANSI/CAN/UL 9540:2023 (maker-hosted copy, SGSNA/26/SZ/00141) Rev Effective 08 April 2026 · Checked · Earlier documentLocation: PDF page 2, printed Page 2 of 3, Technical Data table, FP-Nano-S4-O column
Documented
2 specs not documented yet: usable energy, dimensionsHelp fill in ›
This figure is printed on the California Energy Commission Solar Equipment List (data unchanged since October 1, 2026) as submitted for the listing. No maker document in the catalog prints it for this model yet.
Listed as "Lithium Iron Phosphate" under "Technology" on the California Energy Commission list (data unchanged since October 1, 2026; downloaded October 11, 2026).
Issuer record: CEC Battery List, official spreadsheet (data unchanged since October 1, 2026; downloaded October 11, 2026) October 1, 2026 · Checked · Earlier documentLocation: Row 180, Technology
Documented
This figure is printed on the California Energy Commission Solar Equipment List (data unchanged since October 1, 2026) as submitted for the listing. No maker document in the catalog prints it for this model yet.
Listed as "20.48" under "Nameplate Energy Capacity (kWh)" on the California Energy Commission list (data unchanged since October 1, 2026; downloaded October 11, 2026).
Issuer record: CEC Battery List, official spreadsheet (data unchanged since October 1, 2026; downloaded October 11, 2026) October 1, 2026 · Checked · Earlier documentLocation: Row 180, Nameplate Energy Capacity (kWh)
Documented
Printed Nominal Voltage for the complete DC ESS in a maker-hosted SGS certificate copy, effective 08 April 2026. This records technical data, not independent directory verification.
Official certificate: Fortress Power eSpire Nano outdoor DC ESS SGS certificate of compliance to ANSI/CAN/UL 9540:2023 (maker-hosted copy, SGSNA/26/SZ/00141) Rev Effective 08 April 2026 · Checked · Earlier documentLocation: PDF page 2, printed Page 2 of 3, Technical Data table, FP-Nano-S4-O column
Documented
This figure is printed on the California Energy Commission Solar Equipment List (data unchanged since October 1, 2026) as submitted for the listing. No maker document in the catalog prints it for this model yet.
Listed as "20.48" under "Maximum Continuous Discharge Rate (kW)" on the California Energy Commission list (data unchanged since October 1, 2026; downloaded October 11, 2026).
Issuer record: CEC Battery List, official spreadsheet (data unchanged since October 1, 2026; downloaded October 11, 2026) October 1, 2026 · Checked · Earlier documentLocation: Row 180, Maximum Continuous Discharge Rate (kW)
Documented
Printed Operating Voltage Range for this exact outdoor DC ESS. No series calculation.
Official certificate: Fortress Power eSpire Nano outdoor DC ESS SGS certificate of compliance to ANSI/CAN/UL 9540:2023 (maker-hosted copy, SGSNA/26/SZ/00141) Rev Effective 08 April 2026 · Checked · Earlier documentLocation: PDF page 2, printed Page 2 of 3, Technical Data table, FP-Nano-S4-O column
Documented
Published claims and calculations are not independently tested lifetime output.
Published claims and calculations, not independent test results.
Archived copy captured on 2026-10-11.
Location: Model Number row
Retrieved
Recorded document/effective date: Oct 1, 2026
California Energy Commission Solar Equipment List as downloaded on October 11, 2026 (its data key says updated October 1, 2026). It records that a listed model was submitted with the stated certification, certifying entity and dates; it is a state equipment list, not the certification body's own record, and absence from it says nothing about a product.
Earlier revisions, archived captures and copies published by someone other than the manufacturer. Every one stays reachable.
Archived copy of a document published by Fortress Power. Copyright retained by the publisher; kept for reference and verification only, no endorsement implied. To ask for its removal, email legal@chargedreviews.com.
Archived copy, unaltered, kept as a record of what Fortress Power published. Original address: https://www.fortresspower.com/download/944/espire-nano/47944/fortress-power-espire-nano-ul9540-certification-outdoor.pdf. Copyright and takedown
Embedded dates are file metadata, not independent proof of publication.
SHA-256: 7e09acc65dcea0f93599f3281ddf8081b32463df89707b83c0d029356f4abfac
No warranty terms on file.
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Own one? A verified review needs a receipt and a serial number photo, and counts 19× in the owner rating.
The Evidence score uses the priorities you choose. It counts published documents, such as certificates and warranty terms, and it compares a documented figure with the best documented figure of the same kind. It does not count owner reviews, and it is not a verdict on product quality or on how many people have reviewed it. A low score can mean little is documented, or that a documented figure is below the best of its kind. Undisclosed data scores 0.
Missing for this product: Certificates evidence needed; Warranty term needed; Warranty energy disclosure evidence needed; Lifetime / capacity evidence needed; Cell model disclosure evidence needed.
Industrial/Commercial ESS · High voltage · Energy unconfirmed · Rated capacity
The warranty term and the lifetime energy are each scored against the best documented value for a home storage battery: a value earns its share of that best, times the weight. A documented value always earns points; an undisclosed one earns 0.
No qualifying figure · 20% weight
Not published. No lifetime-production bonus.
Not documented. Undisclosed data scores 0.
Issuer record: CEC Battery List, official spreadsheet (data unchanged since October 1, 2026; downloaded October 11, 2026) October 1, 2026 · Checked · Earlier documentResearch pending, 0 points: Certificates, Warranty term, Warranty energy disclosure, Cell model disclosure.
Computed from public specifications and evidence records. Warranty duration is not service quality; certificate evidence points are not a safety rating. Compatibility and installation limits still apply.
UL 1973: CEC reported · pack check pending
Model FP-Nano-S4-O listed on the California Energy Commission Battery List (data unchanged since October 1, 2026; downloaded October 11, 2026) under Fortress Power LLC, as "FP-Nano-S4-O", CEC listing date 2026-05-21. This is an equipment listing, not UL certification or complete-system approval.
Models: FP-Nano-S4-O
Issuer record: CEC Battery List, official spreadsheet (data unchanged since October 1, 2026; downloaded October 11, 2026) October 1, 2026 · Checked · Earlier documentListed on the California Energy Commission Battery List (data unchanged since October 1, 2026; downloaded October 11, 2026) as Fortress Power LLC "FP-Nano-S4-O": UL 1973, certifying entity SGS, certificate date 2026-04-07, Ed. 3 : 2022. A state equipment list entry, not the certification body's own record.
Models: FP-Nano-S4-O
Issuer record: CEC Battery List, official spreadsheet (data unchanged since October 1, 2026; downloaded October 11, 2026) October 1, 2026 · Checked · Earlier documentNo sourced accessories or replacement parts listed yet.
Manufacturer SKU unknown · US market
Product / system scope unresolved. Model FP-Nano-S4-O listed on the California Energy Commission Battery List (data unchanged since October 1, 2026; downloaded October 11, 2026) under Fortress Power LLC, as "FP-Nano-S4-O", CEC listing date 2026-05-21. This is an equipment listing, not UL certification or complete-system approval.
Issuer record: CEC Battery List, official spreadsheet (data unchanged since October 1, 2026; downloaded October 11, 2026) October 1, 2026 · Checked · Earlier documentProduct / system scope unresolved. Listed on the California Energy Commission Battery List (data unchanged since October 1, 2026; downloaded October 11, 2026) as Fortress Power LLC "FP-Nano-S4-O": UL 1973, certifying entity SGS, certificate date 2026-04-07, Ed. 3 : 2022. A state equipment list entry, not the certification body's own record.
Issuer record: CEC Battery List, official spreadsheet (data unchanged since October 1, 2026; downloaded October 11, 2026) October 1, 2026 · Checked · Earlier documentNo discussions linked yet. Search DIY Solar Forum
No recalls or legal notices on file; this is not a complete recall or court search. All notices · Report a notice
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Prices · price basis. * Calculated; estimates labeled. Value needs confirmation; select it for the reason.
