Growatt SPE 6000 US
For off-grid homes and cabins that want 6 kW of 240 V with a large solar input at a low price. A strong rival to the EG4 6000XP.
Amazon$1,399
The Growatt SPE 6000 US is the better hybrid solar inverter overall, rated 4.1 to 4.0. The Growatt SPE 6000 US leads on efficiency. The Growatt SPE 6000 US costs $150 less ($1,399 vs $1,549).
Fortress Power Solo 6.5K
For off-grid cabins, ADUs and backup systems that want 240 V and a large solar input from a US-supported brand. It costs a little more than the EG4 6000XP.
Current Connected $1,549 Wind & Sun $1,549$1,549
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 Growatt SPE 6000 US for efficiency (95% peak efficiency, 75 W idle vs 93% peak efficiency, 80 W idle).
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 | Growatt SPE 6000 US | Fortress Power Solo 6.5K |
|---|---|---|
| Overall rating | 4.1/5 | 4.0/5 |
| Value 30% | 93 $233 per kW of continuous output | 92 $238 per kW of continuous output |
| Solar input 20% | 68 9,000 W of panels, 550 V max, 2 MPPTs | 69 10,000 W of panels, 550 V max, 2 MPPTs |
| Efficiency 20% | 67 95% peak efficiency, 75 W idle | 52 93% peak efficiency, 80 W idle |
| Features 15% | 82 UL 1741 listed, Wi-Fi add-on, parallel stacking, generator input, battery communication | 85 UL 1741 listed, Wi-Fi app, parallel stacking, generator input, battery communication; no grid sell-back |
| Warranty 15% | 44 5-year warranty | 44 5-year warranty |
Specifications
| Growatt SPE 6000 US | Fortress Power Solo 6.5K | |
|---|---|---|
| Output | ||
| Output voltage | 120/240 V split-phase | 120/240 V split-phase |
| Continuous output | 6,000 W | 6,500 W |
| Surge | - | 13,000 W |
| Peak efficiency | 95% | 93% |
| CEC efficiency | 94.5% | - |
| Idle draw | 75 W | 80 W |
| Transfer time | 20 ms | 10 ms |
| Parallel units | Up to 9 units | Up to 6 units |
| Solar | ||
| Max PV power | 9,000 W | 10,000 W |
| Max PV voltage (Voc) | 550 V | 550 V |
| MPPT range | 60 to 480 V | 150 to 450 V |
| MPPT trackers | 2 | 2 |
| PV current per tracker | 22 A | 18 A |
| Runs without battery | Yes | Yes |
| Battery and grid | ||
| Battery voltage | 48 V | 48 V |
| Battery types | Lithium, lead-acid | Lithium, lead-acid |
| Max charge current | 140 A | 140 A |
| AC charge current | 140 A | 80 A |
| Battery communication | Yes | Yes |
| Grid sell-back | - | No |
| Generator input | Yes | Yes |
| UL 1741 | Yes | Yes |
| Build | ||
| App monitoring | Optional add-on | Included |
| Enclosure | IP20 | IP20 |
| Dimensions | 550 x 465 x 150 mm | 27 x 16.1 x 6.1 in |
| Weight | 47.4 lb | 50.7 lb |
| Warranty | 5 years | 5 years |
| Released | 2025-09 | 2026-01 |