EG4 FlexBOSS21 48V Split-Phase Hybrid Inverter
A 48 V split-phase hybrid inverter rated 12,000 W from battery alone, with three MPPT inputs taking up to 21 kW of solar, an outdoor NEMA 4X case and a Wi-Fi dongle in the box.
$3,600
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Usability
7.3 out of 10It suits a buyer who wants 12 kW of 120/240 V power from batteries and up to 21 kW of solar on one outdoor-rated unit, and who will not need a generator input without adding the GridBOSS or a built-in screen.
Strengths
- 12,000 W continuous from battery alone
- 120/240 V split phase from one unit
- 21 kW PV on 3 MPPTs600 V max
- NEMA 4X enclosure for outdoor mounting
- Wi-Fi dongle and EG4 app included
Drawbacks
- No generator input without the GridBOSS
- Only a standby idle figureunder 65 W, is published
- LCD screen kit sold separately
- Spec sheet allows 16 in parallelstore page says 10
- Manual says 25 kW of PVspec sheet says 21 kW
Specs
- CapacityNot applicable
- AC Output6,000 W or more
- System Voltage48 V
- Panel PowerNot applicable
- Safety ListingCSA 107.1 listed, UL 1741 listed
- Cell TypeNot applicable
- Low-Temp ChargingNot applicable
- Warranty10 Years
- MonitoringWired display or port only
- Weight121.0 lb
Not published by EG4: charge current.
At a glance
- 30.4 x 22.3 x 11.2 in case
- 90 A grid pass-through
- 300 A battery breaker
- Two CTs in the box
EG4 is the brand of EG4 Electronics LLC of Sulphur Springs, Texas, part of Energy Access Innovations with its sister company Signature Solar.
It sells with a cart through Signature Solar at signaturesolar.com and through approved distributors and dealers such as Current Connected, Shop Solar and BigBattery, while eg4electronics.com has no cart.
The EG4 FlexBOSS21 (V1.1), model IV-16000-HYB-AW-FX-XX (XX from 00 to 99), is a 48 V high-frequency, transformerless hybrid inverter that EG4's spec sheet says is capable of running entirely off grid, and that its manual says has the ability to operate off and on the grid. It is rated 12,000 W (50 A) continuous from battery alone and 16,000 W continuous with PV and grid at 25 °C, at 120/240 V split phase or 120/208 V, 6,000 W per leg, with peak ratings of 24,000 W for 0.5 s, 18,000 W for 1 s, 15,000 W for 6 minutes and 13,200 W for 12 minutes, 195 locked rotor amps and 90 A of grid pass-through. Solar input is three MPPT trackers (26, 26 and 15 A), 600 V maximum, a 120-440 V operating range (250-440 V at full power) and a 21 kW recommended array. The battery side is 51.2 V nominal (40-60 V) with 250 A maximum charge and discharge current, CAN and RS485 closed-loop communication, two pairs of battery terminals and a 300 A battery breaker; EG4 recommends at least 600 Ah of battery per inverter. EG4 rates battery-to-load efficiency at 94%, PV-to-load at 97% and CEC weighted efficiency at 97%, standby idle consumption under 65 W, and a transfer time of 20 ms by default or 10 ms when configured. In the box: the inverter, a Wi-Fi dongle, two 1 in CTs, battery and parallel communication cables, a mounting bracket, L brackets, RJ45 terminals, fixings and the manual; the EG4 FlexBOSS21 LCD Screen Kit is sold separately. Generator, smart-load and AC-coupling functions come with EG4's GridBOSS. It has a NEMA 4X enclosure, runs from -25 to 60 °C (derating above 45 °C), is rated under 50 dB at 3 ft, measures 773 x 566 x 285 mm (30.43 x 22.28 x 11.22 in) and weighs 121 lb (55 kg). EG4's 10-year warranty must be registered within the first year or backed by proof of purchase from an EG4 authorized distributor. EG4 sells it through its sister company Signature Solar.
