PowMr POW-LVM4K-ECO
#1 in 120 VFull review
For a small 120 V cabin, shed or van system on a 24 V battery at the lowest price. Buyers who want published efficiency and a UL listing should spend more.
Amazon PowMr $289$289
The PowMr POW-LVM4K-ECO is the better hybrid solar inverter overall, rated 3.4 to 2.9. The PowMr POW-LVM4K-ECO leads on value. The Growatt SPF 3500TL LVM-US wins on features and warranty. The PowMr POW-LVM4K-ECO costs $410 less ($289 vs $699).
Growatt SPF 3500TL LVM-US
#10 in 120 VFull review
For a cabin, shed or backup circuit that needs 3.5 kW of 120 V power from a 48 V battery at a low price. Add a second unit later for 240 V.
Amazon$699
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 PowMr POW-LVM4K-ECO for value ($72 per kW of continuous output vs $200 per kW of continuous output).
- Choose the Growatt SPF 3500TL LVM-US for features (UL 1741 listed, Wi-Fi add-on, parallel stacking; no grid sell-back vs Wi-Fi add-on; not UL 1741 listed) and warranty (2-year warranty vs 1-year warranty).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every 120 V hybrid solar inverter; a clear win is highlighted. How we rank explains each one.
| Factor weight | PowMr POW-LVM4K-ECO | Growatt SPF 3500TL LVM-US |
|---|---|---|
| Overall rating | 3.4/5 | 2.9/5 |
| Value 30% | 100 $72 per kW of continuous output | 67 $200 per kW of continuous output |
| Solar input 20% | 55 5,000 W of panels, 500 V max | 34 4,500 W of panels, 280 V max, 1 MPPT |
| Efficiency 20% | 50 efficiency and idle draw not published (neutral score used) | 17 90% peak efficiency, 60 W idle |
| Features 15% | 20 Wi-Fi add-on; not UL 1741 listed | 60 UL 1741 listed, Wi-Fi add-on, parallel stacking; no grid sell-back |
| Warranty 15% | 0 1-year warranty | 11 2-year warranty |
Specifications
| PowMr POW-LVM4K-ECO | Growatt SPF 3500TL LVM-US | |
|---|---|---|
| Output | ||
| Output voltage | 120 V single-phase | 120 V single-phase |
| Continuous output | 4,000 W | 3,500 W |
| Surge | - | 7,000 W |
| Peak efficiency | - | 90% |
| Idle draw | - | 60 W |
| Transfer time | - | 10 ms |
| Parallel units | No | Up to 6 units |
| Solar | ||
| Max PV power | 5,000 W | 4,500 W |
| Max PV voltage (Voc) | 500 V | 280 V |
| MPPT range | 60 to 450 V | 120 to 225 V |
| MPPT trackers | - | 1 |
| PV current per tracker | - | 22 A |
| Runs without battery | Yes | Yes |
| Battery and grid | ||
| Battery voltage | 24 V | 48 V |
| Battery types | Lithium, lead-acid, user-defined | Lithium, lead-acid |
| Max charge current | - | 80 A |
| AC charge current | 100 A | 40 A |
| Grid sell-back | No | No |
| Generator input | - | No |
| UL 1741 | No | Yes |
| Build | ||
| App monitoring | Optional add-on | Optional add-on |
| Enclosure | - | IP20 (NEMA Type 1) |
| Dimensions | - | 330 x 485 x 135 mm |
| Weight | - | 26.5 lb |
| Warranty | 1 year | 2 years |
| Released | - | 2023-02 |