OutBack Radian GS4048A
For a small off-grid home that needs 240 V for a well pump but only 4 kW of steady load. Hard to find now, so check stock before designing around it.
Solar Cellz USA $2,995.75$2,995.75
The OutBack Radian GS4048A rates 3.7 among split-phase inverter-chargers 48V inverters; the Cotek SP-4000-148 rates 2.3 among over 1,500 W ones. The Cotek SP-4000-148 costs $1,679.75 less ($1,316 vs $2,995.75).
Cotek SP-4000-148
#17 in Over 1,500 WFull review
A 4,000 W hardwired inverter for a 48 V off-grid panel feed, with good efficiency but a short warranty.
Amazon $1,316$1,316
Prices were last checked October 24, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
Scores side by side
These two sit in different size classes (split-phase inverter-chargers and over 1,500 W), and each is scored against the reference points for its own class, so a rating says how well each does among its own size peers. How we rank explains each factor.
| Factor weight | OutBack Radian GS4048A | Cotek SP-4000-148 |
|---|---|---|
| Overall rating | 3.7/5 | 2.3/5 |
| Value 30% | 0 $0.75 per continuous watt | 33 $0.33 per continuous watt |
| Idle draw 15% | 95 34 W idle with nothing plugged in | 5 48 W idle with nothing plugged in |
| Safety listing 15% | 100 ETL listed to UL 1741 (2nd Ed. with supplement SA) and CSA C22.2 No. 107.1 | 0 no UL 458 or UL 1741 listing stated |
| Warranty 15% | 100 5-year warranty | 25 2-year warranty |
| Features 15% | 70 optional remote, app add-on, lithium charge profile, 120/240 V split-phase, hardwire terminal | 20 optional remote, hardwire terminal; no app |
| Efficiency 10% | 89 93% peak efficiency (maker rating) | 67 91% peak efficiency (maker rating) |
Specifications
| OutBack Radian GS4048A | Cotek SP-4000-148 | |
|---|---|---|
| Output | ||
| Type | Pure sine wave inverter-charger | Pure sine wave inverter |
| AC output | 120/240 V split-phase | 120 V |
| Continuous power | 4,000 W | 4,000 W |
| Surge power | 6,000 W for 5 s | 8,000 W for 1 s |
| DC input range | 40 to 64 V | 42 to 66 V |
| Idle draw | 34 W (0.7 A at 48 V) | 48 W (1 A at 48 V) |
| Power-saving draw | 10 W | 4.8 W |
| Peak efficiency | 93% | 91% |
| Connections | ||
| AC outlets | 0 | 0 |
| GFCI outlets | No | No |
| Hardwire terminal | Yes | Yes |
| USB ports | None | None |
| Transfer switch | Yes | No |
| Pass-through rating | 50 A | - |
| Charger | 57.5 A | - |
| Lithium charge profile | Yes | - |
| Parallel units | Yes | No |
| Control and build | ||
| Remote | Optional extra | Optional extra |
| App | Optional add-on | No |
| Display | No | No |
| Safety listing | ETL listed to UL 1741 (2nd Ed. with supplement SA) and CSA C22.2 No. 107.1 | No |
| Design | Low-frequency (transformer) | - |
| Cooling | fan | load-controlled fan |
| Dimensions | 28 x 16 x 8.75 in (71.1 x 40.6 x 22.2 cm) | 255 x 158 x 462 mm (10.0 x 6.2 x 18.2 in) |
| Weight | 82 lb | 22 lb |
| Warranty | 5 years | 2 years |
| Released | 2013-11 | - |