EG4 FlexBOSS18
For grid-tied homes that want net metering and whole-home backup at a lower price than the FlexBOSS21. Choose the 21 if you need more battery-only output or a third tracker.
Signature Solar $3,199.99$3,199.99
The EG4 FlexBOSS18 is the better hybrid solar inverter overall, rated 4.4 to 3.6. The EG4 FlexBOSS18 leads on warranty, solar input and features. The ECO-WORTHY Liber 10KP wins on value. The ECO-WORTHY Liber 10KP costs $1,690 less ($1,509.99 vs $3,199.99).
ECO-WORTHY Liber 10KP
For off-grid homes that want 10 kW of split-phase power and a big solar array at a low price per kW. It shares its hardware with SRNE’s ASP 10 kW.
Amazon ECO-WORTHY $1,509.99$1,509.99
Prices were last checked October 23, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
Which should you buy?
- Choose the EG4 FlexBOSS18 for warranty (10-year warranty vs 2-year warranty), solar input (18,000 W of panels, 600 V max, 2 MPPTs vs 11,000 W of panels, 500 V max, 2 MPPTs) and features (UL 1741 listed, Wi-Fi app, parallel stacking, grid sell-back, battery communication vs UL 1741 listed, Wi-Fi app, parallel stacking; no grid sell-back).
- Choose the ECO-WORTHY Liber 10KP for value ($151 per kW of continuous output vs $320 per kW of continuous output).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every 120/240 V split-phase hybrid solar inverter; a clear win is highlighted. How we rank explains each one.
| Factor weight | EG4 FlexBOSS18 | ECO-WORTHY Liber 10KP |
|---|---|---|
| Overall rating | 4.4/5 | 3.6/5 |
| Value 30% | 76 $320 per kW of continuous output | 100 $151 per kW of continuous output |
| Solar input 20% | 82 18,000 W of panels, 600 V max, 2 MPPTs | 48 11,000 W of panels, 500 V max, 2 MPPTs |
| Efficiency 20% | 68 94% peak efficiency, 60 W idle | 38 92% peak efficiency |
| Features 15% | 95 UL 1741 listed, Wi-Fi app, parallel stacking, grid sell-back, battery communication | 70 UL 1741 listed, Wi-Fi app, parallel stacking; no grid sell-back |
| Warranty 15% | 100 10-year warranty | 11 2-year warranty |
Specifications
| EG4 FlexBOSS18 | ECO-WORTHY Liber 10KP | |
|---|---|---|
| Output | ||
| Output voltage | 120/240 V split-phase | 120/240 V split-phase |
| Continuous output | 10,000 W | 10,000 W |
| Surge | 20,000 W | 20,000 W |
| Peak efficiency | 94% | 92% |
| CEC efficiency | 97% | - |
| Idle draw | 60 W | - |
| Transfer time | 20 ms | 10 ms |
| Parallel units | Up to 16 units | Up to 6 units |
| Solar | ||
| Max PV power | 18,000 W | 11,000 W |
| Max PV voltage (Voc) | 600 V | 500 V |
| MPPT range | 120 to 440 V | 125 to 425 V |
| MPPT trackers | 2 | 2 |
| PV current per tracker | 26 A | 22 A |
| Runs without battery | - | Yes |
| Battery and grid | ||
| Battery voltage | 48 V | 48 V |
| Battery types | Lithium, lead-acid | Lithium-ion, lead-acid, user-defined |
| Max charge current | 208 A | 200 A |
| AC charge current | - | 120 A |
| Battery communication | Yes | - |
| Grid sell-back | Yes | No |
| Generator input | - | No |
| UL 1741 | UL 1741 SB | Yes |
| Build | ||
| App monitoring | Included | Included |
| Enclosure | NEMA 4X | IP20 |
| Dimensions | 30.43 x 22.28 x 11.22 in | 620 x 445 x 130 mm |
| Weight | 115 lb | 59.5 lb |
| Warranty | 10 years | 2 years |
| Released | 2025-03 | 2026-03 |