Manufacturer and seller images. Configuration examples may include additional equipment.
Image source: EG4 FlexBOSS21 front view published by EG4 Electronics on its own product page for SKU EG4INV240V50AFLXBOSS.Paid link · price checked
Part number shown by distributor; exact hardware revision should be checked on the label.
Distributor product page: Current Connected product listing Paid link.CheckedProvisional evidence
Model-specific manufacturer datasheet.
Official datasheet: EG4 FlexBOSS21 datasheet Rev 1.3.0 · CheckedDocumented
Printed as "PEAK POWER 24000W (.5 sec) | 18000W (1 sec) | 15000W (6 min) | 13200W (12 min)" in the EG4 FlexBOSS21 spec sheet v1.3.0, captured on September 25, 2026.
Official datasheet: EG4 FlexBOSS21 datasheet Rev 1.3.0 · CheckedLocation: Spec sheet, AC OUT, "PEAK POWER" row
Documented
Model-specific manufacturer datasheet.
Official datasheet: EG4 FlexBOSS21 datasheet Rev 1.3.0 · CheckedDocumented
Model-specific manufacturer datasheet.
Official datasheet: EG4 FlexBOSS21 datasheet Rev 1.3.0 · CheckedCalculated
Printed as "MAX. EFFICIENCY: PV TO GRID/LOAD 97%" in the EG4 FlexBOSS21 spec sheet v1.3.0, captured on September 25, 2026. The same block prints CEC weighted 97%, battery to grid/load 94%, PV to battery 94.5% and AC to battery 94%. Manufacturer rating; no test conditions are given.
Official datasheet: EG4 FlexBOSS21 datasheet Rev 1.3.0 · CheckedLocation: Spec sheet, EFFICIENCY block, "MAX. EFFICIENCY: PV TO GRID/LOAD" row
Documented
Usable or recommended array power, not AC output. String voltage/current limits also apply.
Official datasheet: EG4 FlexBOSS21 datasheet Rev 1.3.0 · CheckedDocumented
Printed as "PEAK POWER 24000W (.5 sec) | 18000W (1 sec) | 15000W (6 min) | 13200W (12 min)" in the EG4 FlexBOSS21 spec sheet v1.3.0, captured on September 25, 2026.
Official datasheet: EG4 FlexBOSS21 datasheet Rev 1.3.0 · CheckedLocation: Spec sheet, AC OUT, "PEAK POWER" row
Documented
Model-specific manufacturer datasheet.
Official datasheet: EG4 FlexBOSS21 datasheet Rev 1.3.0 · CheckedDocumented
Printed as "MAX. EFFICIENCY: PV TO GRID/LOAD 97%" in the EG4 FlexBOSS21 spec sheet v1.3.0, captured on September 25, 2026. The same block prints CEC weighted 97%, battery to grid/load 94%, PV to battery 94.5% and AC to battery 94%. Manufacturer rating; no test conditions are given.
Official datasheet: EG4 FlexBOSS21 datasheet Rev 1.3.0 · CheckedLocation: Spec sheet, EFFICIENCY block, "MAX. EFFICIENCY: PV TO GRID/LOAD" row
Documented
Printed as "NOMINAL OUTPUT VOLTAGE 120/240 VAC; 120/208 VAC (L1/L2/N required)" in the EG4 FlexBOSS21 spec sheet v1.3.0, captured on September 25, 2026.
Official datasheet: EG4 FlexBOSS21 datasheet Rev 1.3.0 · CheckedLocation: Spec sheet, AC OUT, "NOMINAL OUTPUT VOLTAGE" row
Documented
Printed as "BATTERY NOMINAL VOLTAGE 51.2 VDC" in EG4 FlexBOSS21 manual v1.3.7, Technical specifications, Battery data. Revised on 1 October 2026: The manual and datasheet print the battery nominal voltage as 51.2 VDC; the datasheet's "48V split-phase" is a product description, not a nominal voltage rating.
Official instruction manual: EG4 FlexBOSS21 manual v1.3.7 Rev 1.3.7 · Checked · Earlier documentLocation: Technical specifications, Battery data
Documented
Model-specific manufacturer datasheet.
Official datasheet: EG4 FlexBOSS21 datasheet Rev 1.3.0 · CheckedDocumented
Maximum with PV contribution; see battery-only output.
Official datasheet: EG4 FlexBOSS21 datasheet Rev 1.3.0 · CheckedDocumented
Usable or recommended array power, not AC output. String voltage/current limits also apply.
Official datasheet: EG4 FlexBOSS21 datasheet Rev 1.3.0 · CheckedDocumented
Absolute voltage limit. Recommended design maximum can be lower; use the current manual and cold-weather string calculation.
Official datasheet: EG4 FlexBOSS21 datasheet Rev 1.3.0 · CheckedDocumented
Model-specific manufacturer datasheet.
Official datasheet: EG4 FlexBOSS21 datasheet Rev 1.3.0 · CheckedDocumented
Model-specific manufacturer datasheet.
Official datasheet: EG4 FlexBOSS21 datasheet Rev 1.3.0 · CheckedCalculated
Model-specific manufacturer datasheet.
Official datasheet: EG4 FlexBOSS21 datasheet Rev 1.3.0 · CheckedDocumented
Printed as "2 4 1/0 AWG (53.5mm2) 340A 16 ft. Max. 230 in-lbs. (26Nm) 300A ..." in the EG4 FlexBOSS21 manual, Table 9.1, Battery Connections, captured on September 26, 2026.
Official instruction manual: EG4 FlexBOSS21 manual v1.3.7 Rev 1.3.7 · Checked · Earlier documentLocation: Table 9.1, Battery Connections
Documented
Printed as "Grid 90A 2 AWG (50 mm2) 93 in-lbs. (10.5Nm)" in the EG4 FlexBOSS21 manual, AC connections table, captured on September 26, 2026.
Official instruction manual: EG4 FlexBOSS21 manual v1.3.7 Rev 1.3.7 · Checked · Earlier documentLocation: AC connections table
Documented
Model-specific manufacturer datasheet.
Official datasheet: EG4 FlexBOSS21 datasheet Rev 1.3.0 · CheckedDocumented
Printed as "230 in-lbs. (26Nm)" in the EG4 FlexBOSS21 manual, Table 9.1, Battery Connections, captured on September 26, 2026. Battery terminal torque.
Official instruction manual: EG4 FlexBOSS21 manual v1.3.7 Rev 1.3.7 · Checked · Earlier documentLocation: Table 9.1, Battery Connections
Documented
Printed as "Load 90A 2 AWG (50 mm2) 93 in-lbs. (10.5Nm)" in the EG4 FlexBOSS21 manual, AC connections table, captured on September 26, 2026.
Official instruction manual: EG4 FlexBOSS21 manual v1.3.7 Rev 1.3.7 · Checked · Earlier documentLocation: AC connections table
Documented
Published claims and calculations, not independent test results.
Manufacturer document claim for the named equipment. Issuer listing, exact revision and current status have not been independently checked. This is not a complete installed-system approval.
Manufacturer document
Official datasheet: EG4 FlexBOSS21 datasheet Rev 1.3.0 · CheckedManufacturer specification, not an independent test.
Location: Printed model column and specification table
Retrieved
SHA-256: 8c18423580e8bd9589851618c137ccac4515eb5e8a638039b51926c2bd0b2c50
Official datasheet: EG4 FlexBOSS21 datasheet Rev 1.3.0 · CheckedArchived copy of a document published by EG4 Electronics. 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 EG4 Electronics published. Original address: https://eg4electronics.com/wp-content/uploads/2024/10/EG4-FlexBoss21-Spec-Sheet.pdf. Copyright and takedown
Embedded dates are file metadata, not independent proof of publication.
SHA-256: 8c18423580e8bd9589851618c137ccac4515eb5e8a638039b51926c2bd0b2c50
Document group: manual. Exact SKU named in document text: not found.
Location: Linked from https://eg4electronics.com/categories/inverters/eg4-flexboss-21/ with the link text "EG4 FlexBOSS21 – User Manual (Spanish) v1.3.2"
Retrieved
PDF downloaded from the link the manufacturer publishes on its own product page for this model and preserved byte for byte. It establishes the document that link served on the access date; the document's text was read but does not repeat this exact SKU, so it is recorded as the document the manufacturer links for this product rather than as a per-SKU document. No revision history, issuer verification or continued availability of the link is established.
Official product page: EG4 Electronics product page: EG4® FlexBOSS21 - EG4 Electronics Checked · Earlier documentArchived copy of a document published by EG4 Electronics. 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 EG4 Electronics published. Original address: https://eg4electronics.com/wp-content/uploads/2025/03/EG4-FlexBOSS21-User-Manual-Spanish-v1.2.0.pdf. Copyright and takedown
Embedded dates are file metadata, not independent proof of publication.
SHA-256: 05dd750db6103c9490947374e1ab356df8be0afb805983ce32832a57e239c26a
Distributor listing. Manufacturer or issuer confirmation is separate.
Location: Product identity and specifications
Retrieved
SHA-256: d57539dcd7dd88a2ace34d9e052695bc16ddea7182395ad1af63538876617561
Distributor product page: Current Connected product listing Paid link.CheckedEarlier revisions, archived captures and copies published by someone other than the manufacturer. Every one stays reachable.
Document group: datasheet. Exact SKU named in document text: not found.
Location: Linked from https://eg4electronics.com/categories/inverters/eg4-flexboss-21/ with the link text "EG4 FlexBOSS21 – Spec Sheet (Spanish) v1.2.7"
Retrieved
PDF downloaded from the link the manufacturer publishes on its own product page for this model and preserved byte for byte. It establishes the document that link served on the access date; the document's text was read but does not repeat this exact SKU, so it is recorded as the document the manufacturer links for this product rather than as a per-SKU document. No revision history, issuer verification or continued availability of the link is established.
Official product page: EG4 Electronics product page: EG4® FlexBOSS21 - EG4 Electronics Checked · Earlier documentArchived copy of a document published by EG4 Electronics. 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 EG4 Electronics published. Original address: https://eg4electronics.com/wp-content/uploads/2025/03/EG4-FlexBOSS21-Spec-Sheet-Spanish.pdf. Copyright and takedown
Embedded dates are file metadata, not independent proof of publication.
SHA-256: 38923679ab7dc6c167cc354c8c35a9dea6f956ad381f948224b202f0cf29e14a
Linked from the Current Connected product page with link text "Manual".
Location: FlexBOSS-21-Manual.pdf
Retrieved
Original PDF preserved byte for byte, found linked from the Current Connected listing https://www.currentconnected.com/product/eg4flexboss21. The revision is whatever was published at this URL on the access date; exact variant coverage inside the document was not separately verified and no later revision was checked.
SHA-256: 00d92a71c9b2ca2ccb233c879c86f1708fe215fdfb1bb35ad1f09415a207e2a3
Archived copy of a document published by eg4electronics.com. 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 eg4electronics.com published. Original address: https://eg4electronics.com/wp-content/uploads/2024/08/FlexBOSS-21-Manual.pdf. Copyright and takedown
Embedded dates are file metadata, not independent proof of publication.
SHA-256: 00d92a71c9b2ca2ccb233c879c86f1708fe215fdfb1bb35ad1f09415a207e2a3
Location: Identity block "MODEL #: IV-16000-HYB-AW-* SKU: EG4INV240V50AFLXBOSSV2"; description; Key Specifications
Retrieved
EG4's own product page for the FlexBOSS21 hybrid inverter, captured byte for byte on September 22, 2026. It establishes the identity block "MODEL #: IV-16000-HYB-AW-* SKU: EG4INV240V50AFLXBOSSV2", the description and the Key Specifications block. Both identifiers differ from the catalog record, which holds EG4INV240V50AFLXBOSS as both model and stock keeping unit with no IV-16000 model number at all; the difference is recorded in the identity note rather than written over the recorded value, because the page does not say whether the V2 stock keeping unit marks a hardware change or only a catalogue renumbering. The page prints no price.
Document group: other. Attached by exact model or SKU naming in the document text.
Location: Linked from https://eg4electronics.com/categories/inverters/eg4-12kpv-all-in-one-hybrid-inverter/ with the link text "EG4 Hybrid Inverter RSD Transmitters"
Retrieved
PDF downloaded from a link published on the manufacturer's own site and preserved byte for byte. It establishes the document that link served on the access date. It is attached only to catalog rows whose exact documented SKU or exact model designation appears in this document's own text, so a document covering several models is attached to exactly those rows.
Archived copy of a document published by EG4 Electronics. 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 EG4 Electronics published. Original address: https://eg4electronics.com/wp-content/uploads/2026/01/EG4-Hybrid-Inverter-RSD-Transmitters.pdf. Copyright and takedown
Embedded dates are file metadata, not independent proof of publication.
SHA-256: 03f78861c3ea1dd99131814206e39905b535e5f11f6c4249bc444ef1936e1499
Matched to the catalog record because the manufacturer's documented SKU for this product appears on this page and on no other page captured from this site.
Location: Page title: EG4® FlexBOSS21 - EG4 Electronics
Retrieved
Manufacturer-operated product page, captured byte for byte with a plain HTTPS GET and a desktop user agent. It establishes what the manufacturer published at this URL on the access date for this exact model: the specification table it shows, the page photo and the documents it links. Values rendered only by client-side scripts are not part of the capture. Marketing text, certification wording and stock state remain manufacturer claims that were not independently verified, and nothing on it was applied to any other model.
Archived copy of a document published by EG4 Electronics. 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 EG4 Electronics published. Original address: https://eg4electronics.com/wp-content/uploads/2024/10/EG4-FlexBoss21-Spec-Sheet.pdf. Copyright and takedown
Embedded dates are file metadata, not independent proof of publication.
SHA-256: 8c18423580e8bd9589851618c137ccac4515eb5e8a638039b51926c2bd0b2c50
Archived copy of a document published by EG4 Electronics. 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 EG4 Electronics published. Original address: https://eg4electronics.com/wp-content/uploads/2024/08/FlexBOSS-21-Manual.pdf. Copyright and takedown
Embedded dates are file metadata, not independent proof of publication.
SHA-256: 00d92a71c9b2ca2ccb233c879c86f1708fe215fdfb1bb35ad1f09415a207e2a3
Archived copy of a document published by cdn.currentconnected.com. 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 cdn.currentconnected.com published. Original address: https://cdn.currentconnected.com/2025/05/30122304/EG4-Electronics-FlexBOSS21-and-WallMount-UL9540-Certification.pdfPaid link.. Copyright and takedown
Embedded dates are file metadata, not independent proof of publication.
SHA-256: 2d2bec503bf585d45a45f810be7f4aa9162e2e0fd2e7be501a18b4dcf7abaa5a
Archived copy of a document published by EG4 Electronics. 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 EG4 Electronics published. Original address: https://eg4electronics.com/wp-content/uploads/2025/03/EG4-FlexBOSS21-Spec-Sheet-Spanish.pdf. Copyright and takedown
Embedded dates are file metadata, not independent proof of publication.
SHA-256: 38923679ab7dc6c167cc354c8c35a9dea6f956ad381f948224b202f0cf29e14a
Archived copy of a document published by EG4 Electronics. 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 EG4 Electronics published. Original address: https://eg4electronics.com/wp-content/uploads/2025/03/EG4-FlexBOSS21-User-Manual-Spanish-v1.2.0.pdf. Copyright and takedown
Embedded dates are file metadata, not independent proof of publication.
SHA-256: 05dd750db6103c9490947374e1ab356df8be0afb805983ce32832a57e239c26a
Archived copy of a document published by EG4 Electronics. 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 EG4 Electronics published. Original address: https://eg4electronics.com/wp-content/uploads/2025/10/EG4-UL-9540-ESS-Model-Number-Explanation-Hybrids-with-All-Weather-Indoor-WallMount.pdf. Copyright and takedown
Embedded dates are file metadata, not independent proof of publication.
SHA-256: 9710b53a50bd057e57badf0c594df3977a1e80b3d18048c3a950ddb711d2b319
Archived copy of a document published by EG4 Electronics. 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 EG4 Electronics published. Original address: https://eg4electronics.com/wp-content/uploads/2025/08/Busbar-PCS-Explained.pdf. Copyright and takedown
Embedded dates are file metadata, not independent proof of publication.
SHA-256: ab33ecf2e74b31387fc74f72150a150673a93dbdb5b2d6750a5afb880e5a1d6c
Archived copy of a document published by EG4 Electronics. 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 EG4 Electronics published. Original address: https://eg4electronics.com/wp-content/uploads/2025/07/EG4-Hybrid-Inverters-Manufacturers-Statement-for-Anti-Islanding-Methods.pdf. Copyright and takedown
Embedded dates are file metadata, not independent proof of publication.
SHA-256: 4e4206191267b5128ac869efd61447035640c9566091391e4190f4ed7b4032db
Archived copy of a document published by EG4 Electronics. 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 EG4 Electronics published. Original address: https://eg4electronics.com/wp-content/uploads/2024/11/ChangeLog-1E1E-Firmware-Benefits-At-A-Glance.pdf. Copyright and takedown
Embedded dates are file metadata, not independent proof of publication.
SHA-256: 47f39d7ba3dcdd3698c7e7b2159b4cab98024b93f2a42543721fa49ba5adcc41
Archived copy of a document published by EG4 Electronics. 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 EG4 Electronics published. Original address: https://eg4electronics.com/wp-content/uploads/2025/03/EG4-NEC-Code-Compliance-for-AC-DC-Disconnects.pdf. Copyright and takedown
Embedded dates are file metadata, not independent proof of publication.
SHA-256: 4073ae2899b001e4c7fbdc39f2ec97fd08734018110d9b3cc2086582d8d2a7cd
Archived copy of a document published by EG4 Electronics. 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 EG4 Electronics published. Original address: https://eg4electronics.com/wp-content/uploads/2024/11/EG4-FlexBoss21-COC.pdf. Copyright and takedown
Embedded dates are file metadata, not independent proof of publication.
SHA-256: d684c0553605420da2ffa39d4f64b961603f6d6d086eb3daa0f39f05767f0086
Archived copy of a document published by EG4 Electronics. 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 EG4 Electronics published. Original address: https://eg4electronics.com/wp-content/uploads/2025/08/EG4-FlexBOSS21-FlexBOSS18-UL-3141-CRD-PCS-Verification-of-Conformity.pdf. Copyright and takedown
Embedded dates are file metadata, not independent proof of publication.
SHA-256: c091f1ff4364cf5d06876470ff9229c47ad7c301553de7f4d1798501971556ac
Archived copy of a document published by EG4 Electronics. 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 EG4 Electronics published. Original address: https://eg4electronics.com/wp-content/uploads/2025/08/EG4-FlexBOSS18-WALLMOUNT-ALL-WEATHER-ESS-–-UL-9540-CERTIFICATE-OF-COMPLIANCE.pdf. Copyright and takedown
Embedded dates are file metadata, not independent proof of publication.
SHA-256: eecf515761aff73db2b868e0bf26b74a506853b7edcaf821a0a98f901b8653cd
Archived copy of a document published by EG4 Electronics. 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 EG4 Electronics published. Original address: https://eg4electronics.com/wp-content/uploads/2025/03/EG4-FlexBOSS21-280Ah-Indoor-WallMount-UL-9540-COC.pdf. Copyright and takedown
Embedded dates are file metadata, not independent proof of publication.
SHA-256: 7106a515efc1564738754c3dcd98a0ddae5bd30f7df0aa5c05ae0efc0b109995
Archived copy of a document published by EG4 Electronics. 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 EG4 Electronics published. Original address: https://eg4electronics.com/wp-content/uploads/2025/12/EG4-FlexBOSS21-FlexBOSS18-WallMount-314Ah-Indoor-Battery-ESS-–-UL-9540-Certificate-of-Compliance.pdf. Copyright and takedown
Embedded dates are file metadata, not independent proof of publication.
SHA-256: ea8b85d0521639b68cb4ecc810a3e8e3a4efed502982e012f755fd6b0fef9dad
Archived copy of a document published by EG4 Electronics. 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 EG4 Electronics published. Original address: https://eg4electronics.com/wp-content/uploads/2026/01/EG4-Hybrid-Inverter-RSD-Transmitters.pdf. Copyright and takedown
Embedded dates are file metadata, not independent proof of publication.
SHA-256: 03f78861c3ea1dd99131814206e39905b535e5f11f6c4249bc444ef1936e1499
Datasheet headline; registration, operating limits and full contract terms apply.
Official datasheet: EG4 FlexBOSS21 datasheet Rev 1.3.0 · CheckedDocumented
Affiliate links below. Affiliate disclosure
Price for one unit, as listed by the seller. Does not include tax, shipping and installation. Price checked .
The seller lists this as a new unit. Condition checked .
Distributor product page: EG4 FlexBOSS21 48V Hybrid All-in-One Inverter, 12kW-16kW AC Output, UL 1741 & UL 9540 Solar Inverter (www.currentconnected.com, October 3, 2026 capture) Paid link.Checked · Earlier documentChecked · End date not published.
Signature Solar promotion terms Paid link.Price for one unit, as listed by the seller. Does not include tax and shipping. Price checked .
The seller lists this as a new unit. Condition checked .
Minimum order: 1 units. Checked .
Distributor product page: EG4 FlexBOSS21 16kW AC Hybrid Inverter (signaturesolar.com, October 4, 2026 capture) Paid link.Checked · Earlier documentDistributor product page: EG4 FlexBOSS21 16kW AC Hybrid Inverter (signaturesolar.com, November 2, 2026 capture) Paid link.Checked · Earlier documentPrice for one unit, as listed by the seller. Does not include tax and shipping. Price checked .
The seller lists this as a new unit. Condition checked .
Distributor product page: BigBattery store catalog row for SKU INV027: EG4 FlexBOSS21 Hybrid Solar Inverter | 21kW PV / 16kW AC | Split-Phase | 4-MPPT | Scalable | Remote Wi-Fi Monitoring (MiMo capture bigbattery.json, captured 2026-10-27T15:39:27Z) CheckedPrices we read at Current Connected, Signature Solar and BigBattery · 66 readings from to
Since · Listing price (USD)
A break in a line is a gap in our readings: no price is drawn for days we did not read.
| Checked (UTC) | Seller | Price |
|---|---|---|
| Sep 20, 2026, 7:52 AM PDT | Current Connected Paid link. | $3,599.99 |
| Sep 23, 2026, 4:51 AM PDT | Current Connected Paid link. | $3,599.99 |
| Sep 25, 2026, 2:00 AM PDT | Current Connected Paid link. | $3,599.99 |
| Sep 26, 2026, 2:32 AM PDT | Current Connected Paid link. | $3,599.99 |
| Sep 27, 2026, 3:32 AM PDT | Current Connected Paid link. | $3,599.99 |
| Sep 28, 2026, 4:32 AM PDT | Current Connected Paid link. | $3,599.99 |
| Sep 29, 2026, 3:54 PM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 1, 2026, 1:06 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 2, 2026, 1:06 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 3, 2026, 1:06 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 3, 2026, 11:53 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 4, 2026, 1:06 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 4, 2026, 9:17 AM PDT | Signature Solar Paid link. | $3,599.99 |
| Oct 5, 2026, 1:05 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 6, 2026, 1:05 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 7, 2026, 1:15 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 8, 2026, 1:05 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 9, 2026, 1:25 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 10, 2026, 1:46 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 11, 2026, 1:05 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 12, 2026, 1:26 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 13, 2026, 1:15 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 14, 2026, 1:25 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 15, 2026, 1:06 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 16, 2026, 1:05 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 17, 2026, 1:15 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 18, 2026, 1:05 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 19, 2026, 1:45 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 20, 2026, 1:36 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 21, 2026, 1:36 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 22, 2026, 1:16 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 23, 2026, 2:09 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 24, 2026, 1:06 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 24, 2026, 3:03 AM PDT | Signature Solar Paid link. | $3,599.99 |
| Oct 25, 2026, 1:06 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 26, 2026, 1:07 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 27, 2026, 1:06 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 27, 2026, 2:53 AM PDT | Signature Solar Paid link. | $3,599.99 |
| Oct 27, 2026, 8:39 AM PDT | BigBattery Paid link. | $3,599.99 |
| Oct 28, 2026, 1:26 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 28, 2026, 3:22 AM PDT | Signature Solar Paid link. | $3,599.99 |
| Oct 29, 2026, 1:16 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 29, 2026, 3:46 AM PDT | Signature Solar Paid link. | $3,599.99 |
| Oct 30, 2026, 1:26 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 30, 2026, 3:50 AM PDT | Signature Solar Paid link. | $3,599.99 |
| Oct 31, 2026, 1:26 AM PDT | Current Connected Paid link. | $3,599.99 |
| Oct 31, 2026, 3:34 AM PDT | Signature Solar Paid link. | $3,599.99 |
| Nov 1, 2026, 1:06 AM PDT | Current Connected Paid link. | $3,599.99 |
| Nov 1, 2026, 3:45 AM PST | Signature Solar Paid link. | $3,599.99 |
| Nov 2, 2026, 1:36 AM PST | Current Connected Paid link. | $3,599.99 |
| Nov 2, 2026, 4:07 AM PST | Signature Solar Paid link. | $3,599.99 |
| Nov 2, 2026, 9:18 AM PST | Signature Solar Paid link. | $3,599.99 |
| Nov 3, 2026, 1:06 AM PST | Current Connected Paid link. | $3,599.99 |
| Nov 3, 2026, 4:22 AM PST | Signature Solar Paid link. | $3,599.99 |
| Nov 4, 2026, 1:06 AM PST | Current Connected Paid link. | $3,599.99 |
| Nov 5, 2026, 1:06 AM PST | Current Connected Paid link. | $3,599.99 |
| Nov 5, 2026, 2:12 AM PST | Signature Solar Paid link. | $3,599.99 |
| Nov 6, 2026, 1:06 AM PST | Current Connected Paid link. | $3,599.99 |
| Nov 7, 2026, 1:16 AM PST | Current Connected Paid link. | $3,599.99 |
| Nov 7, 2026, 3:16 AM PST | Signature Solar Paid link. | $3,599.99 |
| Nov 8, 2026, 1:16 AM PST | Current Connected Paid link. | $3,599.99 |
| Nov 9, 2026, 1:16 AM PST | Current Connected Paid link. | $3,599.99 |
| Nov 10, 2026, 1:06 AM PST | Current Connected Paid link. | $3,599.99 |
| Nov 11, 2026, 1:36 AM PST | Current Connected Paid link. | $3,599.99 |
| Nov 11, 2026, 2:12 AM PST | Signature Solar Paid link. | $3,599.99 |
| Nov 12, 2026, 1:26 AM PST | Current Connected Paid link. | $3,599.99 |
Recent reviews count from the latest approved revision. Verified reviews carry 19× the weight. Select a period to filter.
Showing 3 of 3 reviews
I have the 1st gen version of the FB21. Since it's out in the barn some 80"+- from the house the fan noise is not an issue. That said it seems to be 55-60 decibels with the fans running. Other than the need to reboot the inverter after a firmware update ( It would not export power till after the reboot). it's been flawless for me. However my average power draw (not counting the grid export) when not charging the car is under 3-4kW 90+% of the time. The car is a Chev Volt so make charge rate is only 3.85kW for it. My export limit is only 10kVa due to the transformer the utility installed back in 1983 when I built the house. Yes I would buy this again. I have the FB21 and GridBoss connected to home assistant for data collection and monitoring. The changes I have made to the configuration of the units have all been thru the EG4 app/website. After a fine tuning of the settings for how I want my system to run. I have been very happy with it. As of Oct 2026 and 17 months of operation I have produced 31.03mWh of Solar. My last 3 electric bills were $0.17 each for the month (Sales tax is not offset but the energy sales). For the Winter 2025-2026 I used a total of 357kWh of imported power from the grid. The rest was self consumption from solar or the 64kWh battery bank.
Delivery: On time
Very happy with sales support. Only contact with Tech to to troubleshoot the issue with unable to get configuration changes to "stick" after a firmware update. Forget how long on the phone but it was pretty painless. I have not had any issues or problems with any of the items from Signature Solar since I made my purchase.
I installed this system as a DIY project over the Christmas holidays in 2025, getting formal PTO from by PoCo in February 2026. This was a permitted and inspected install The total system is 25 kW of solar goodness, including 8 kW of AC couple on the GridBoss. It has been operating without a hitch for 9 months straight, mostly self-consumption. The installation was easy, with the FlexBoss mounted on the outside of the BossBox. Getting 3x300 pound batteries in the BossBox was the painful part, not the inverter. The firmware stabilized with FAAB-2727 and my only complaints are minor. First that the web and app monitor don't take into account AC Coupled solar fed into the GridBoss, so the reported total solar production says 15.2 MWh. My AC Coupled adds another 7.3 MWh, so while it shows in the flow on the monitor, the totals aren't totaled. The simple TLDR is it has just worked for 9 straight months without any issues.
A few software glitches at the beginning; however, it has since been patched with firmware updates. Had one instance where the output got stuck in grid bypass mode after a heavy storm. EG4 support got me back up and running on solar in about an hour. I was quite surprised by the customer support. Has been very reliable over the last 2 years, day in and day out. I've put over 35 MWhs of solar through this unit so far.
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 details. This number counts only the evidence recorded so far. The source review for this product is not finished, or the maker has not disclosed enough, so the number can only go up.
Missing for this product: Battery conversion efficiency needed; Idle consumption needed.
Each input is scored against the best documented value for an inverter: warranty term and battery conversion efficiency against every published inverter, idle consumption (lower is better) against the inverters in the same output band, or against every published inverter when the output is not documented. A documented value always earns points; an undisclosed one earns 0 and is listed as missing. Researched products receive a score. Certificates earn points for the evidence itself. Size and weight do not affect scores.
Manufacturer claim; issuer verification pending. Applies to the exact inverter.
Official datasheet: EG4 FlexBOSS21 datasheet Rev 1.3.0 · Checked10 of 25 years, the best documented for an inverter (printed by the maker): APsystems DS3
Datasheet headline; registration, operating limits and full contract terms apply.
Official datasheet: EG4 FlexBOSS21 datasheet Rev 1.3.0 · CheckedResearch pending, 0 points: Battery conversion efficiency, Idle consumption.
Warranty term and battery conversion efficiency are compared with every published inverter; idle consumption with the inverters in the same 15 to 50 kW output band. · Method version 0.5
How it worksManufacturer document claim for the named equipment. Issuer listing, exact revision and current status have not been independently checked. This is not a complete installed-system approval.
Models: EG4INV240V50AFLXBOSS
Official datasheet: EG4 FlexBOSS21 datasheet Rev 1.3.0 · CheckedManufacturer document claim for the named equipment. Issuer listing, exact revision and current status have not been independently checked. This is not a complete installed-system approval.
Manufacturer document
Official datasheet: EG4 FlexBOSS21 datasheet Rev 1.3.0 · CheckedNo sourced accessories or replacement parts listed yet.
The stock keeping unit EG4's own FlexBOSS21 page printed on September 22, 2026, one V2 suffix longer than the identifier this record holds.
Official product page: EG4 FlexBOSS21 (September 22, 2026 capture) Checked · Earlier documentThe model number EG4's own FlexBOSS21 page prints, as a wildcard. The record holds no IV-16000 model number at all.
Official product page: EG4 FlexBOSS21 (September 22, 2026 capture) Checked · Earlier documentThe name EG4 Electronics gives this product in its own spec sheet (version 1.3.0), page 1, opening description (the cover prints "MODEL#: IV-16000-HYB-AW-FX-XX" above the title "EG4® FLEXBOSS21 HYBRID INVERTER"): "the FlexBOSS21 supports up to 21kW of PV input". EG4 prints this name for this one product only; the catalog has no other version of it under this name (PM, 2026-10-27).
Official datasheet: Spec Sheet Checked · Earlier documentManufacturer SKU EG4INV240V50AFLXBOSS · US market
Product / system scope unresolved. Manufacturer document claim for the named equipment. Issuer listing, exact revision and current status have not been independently checked. This is not a complete installed-system approval.
Official datasheet: EG4 FlexBOSS21 datasheet Rev 1.3.0 · CheckedWill Prowse ·
Video by Will Prowse, a co-owner of Charged Reviews.
EG4 FlexBOSS21 only; excludes FlexBOSS18. The GridBOSS gateway shown has no catalog record.
Links to DIY Solar Forum threads. The title is the forum's own words. It is a member's experience, not a Charged test, not a verified fault rate, and not a statement by the maker.
No recalls or legal notices on file; this is not a complete recall or court search. All notices · Report a notice
Something wrong that is not one of the values above?
Prices · price basis. * Calculated; estimates labeled. Value needs confirmation; select it for the reason.
