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Ships by freight. This item is too large for parcel delivery. After you order, we'll contact you within 1 business day with the freight cost and delivery options (liftgate, residential). Your order ships only after you approve the quote.
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- FlexBOSS21: 16kW AC with PV, 21kW PV input
- GridBOSS MID v3.1: 200A service entrance
- Up to 3 hybrid inverters on one GridBOSS
- 4 smart load ports, 125A generator input
- NEMA 4X inverter, NEMA 3R GridBOSS
- 10-year warranty on both products
Ships by LTL freight. Too large for parcel delivery. Questions on freight? Call (888) 831-0450.
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The core of an EG4 whole-home system in one box: the FlexBOSS21 hybrid inverter, the GridBOSS MID v3.1 and the 90A breaker that connects them. The pair powers larger loads, maximizes solar production, manages backed-up and non-backed-up circuits, and supports selling excess solar back to the utility where allowed. Add EG4 batteries for storage.
Highlights
- Handles big loads: FlexBOSS21 starts 5-ton AC units
- Whole-home management: GridBOSS ties utility, inverter, generator and smart loads together
- Fewer parts: GridBOSS replaces separate transfer switches and combiner panels
- Scalable: GridBOSS accepts up to three hybrid inverters
What's included
- 1× EG4 FlexBOSS21 hybrid inverter
- 1× EG4 GridBOSS MID v3.1 (200A service entrance)
- 1× BSB 90A AC circuit breaker (FlexBOSS21-compatible)
Key specs
| FlexBOSS21 max AC output | 16kW (PV + grid) / 12kW (battery only) |
| FlexBOSS21 PV input | 21kW, up to 600VDC, 3 MPPTs |
| GridBOSS rating | 200A service entrance |
| GridBOSS inputs | Up to 3 hybrid inverters + 125A generator |
Warranty & shipping
- EG4 warranties: FlexBOSS21 10 years, GridBOSS 10 years
- Combined weight: ~181 lbs
Batteries, solar panels and additional breakers are sold separately.
| Manufacturer | EG4 Electronics (bundle) |
|---|---|
| Bundle SKU | BNDL-E0019-3.1 |
| GridBOSS Transfer Time | ~25 ms |
| Includes | 1x EG4 FlexBOSS21 Hybrid Inverter (16kW (66.7A); 12kW (50A); 21kW (STC)) |
| Includes | 1x EG4 GridBOSS MID v3.1 (Microgrid Interconnect Device (MID); 200A service entrance (350A bus, software limited to 200A); 3 x 90A (12kPV, 18kPV, FlexBOSS18, FlexBOSS21)) |
| Includes | 1x BSB 90A AC Circuit Breaker |
Specifications are from the manufacturer and may change. Questions? Call (888) 831-0450.
EG4 Limited Warranty (per component): FlexBOSS21 10-year limited; GridBOSS 10-year limited
| FlexBOSS21 | 10-year limited |
|---|---|
| GridBOSS | 10-year limited |
| How to claim | contact original place of purchase (Sky Solar USA) / EG4 |
Download: EG4 FlexBOSS21 Warranty Document
Download: EG4 GridBOSS Warranty Document
Manufacturer warranties are provided by the manufacturer. Keep your invoice as proof of purchase. Questions about a warranty claim? Call (888) 831-0450.