OutBack VFXR3648A
For a cabin or off-grid home built around 120 V loads, with room to stack a second unit later. Rugged and code-friendly, but it idles high for its size.
Amazon $2,139$2,139
The OutBack VFXR3648A and the Magnum MS4048-L are evenly matched, rated 3.8 and 3.8. The OutBack VFXR3648A leads on warranty. The Magnum MS4048-L wins on value, idle draw and efficiency. The Magnum MS4048-L costs $113 less ($2,026 vs $2,139).
Magnum MS4048-L
For a 48 V RV, cabin or backup system that needs a rugged, listed 120 V inverter-charger with big surge.
ResSupply $2,026 A1 Solar Store $2,531.49$2,026
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.
Which should you buy?
- Choose the OutBack VFXR3648A for warranty (5-year warranty vs 3-year warranty).
- Choose the Magnum MS4048-L for value ($0.51 per continuous watt vs $0.59 per continuous watt), idle draw (25 W idle with nothing plugged in vs 34 W idle with nothing plugged in) and efficiency (94% peak efficiency (maker rating) vs 93% peak efficiency (maker rating)).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every 120V inverter-chargers 48V inverter; a clear win is highlighted. How we rank explains each one.
| Factor weight | OutBack VFXR3648A | Magnum MS4048-L |
|---|---|---|
| Overall rating | 3.8/5 | 3.8/5 |
| Value 30% | 32 $0.59 per continuous watt | 45 $0.51 per continuous watt |
| Idle draw 15% | 66 34 W idle with nothing plugged in | 79 25 W idle with nothing plugged in |
| Safety listing 15% | 100 ETL listed to UL 1741 (2nd Ed. with supplement SA) | 100 ETL listed to UL/cUL 458 and CSA C22.2 No. 107.1-01; UL 1741 certificate (ATM) |
| Warranty 15% | 100 5-year warranty | 50 3-year warranty |
| Features 15% | 50 optional remote, app add-on, lithium charge profile, hardwire terminal | 50 optional remote, app add-on, lithium charge profile, hardwire terminal |
| Efficiency 10% | 89 93% peak efficiency (maker rating) | 100 94% peak efficiency (maker rating) |
Specifications
| OutBack VFXR3648A | Magnum MS4048-L | |
|---|---|---|
| Output | ||
| Type | Pure sine wave inverter-charger | Pure sine wave inverter-charger |
| AC output | 120 V | 120 V |
| Continuous power | 3,600 W | 4,000 W |
| Surge power | 5,400 W for 5 s | 8,500 W for 5 s |
| DC input range | 42 to 68 V | 36 to 67.6 V |
| Idle draw | 34 W (0.7 A at 48 V) | 25 W (0.5 A at 48 V) |
| Power-saving draw | 9 W | 8 W |
| Peak efficiency | 93% | 94% |
| Connections | ||
| AC outlets | 0 | 0 |
| GFCI outlets | No | No |
| Hardwire terminal | Yes | Yes |
| USB ports | None | None |
| Transfer switch | Yes | Yes |
| Pass-through rating | 60 A | 30 A |
| Charger | 45 A | 60 A |
| Lithium charge profile | Yes | Yes |
| Parallel units | Yes | No |
| Control and build | ||
| Remote | Optional extra | Optional extra |
| App | Optional add-on | Optional add-on |
| Display | No | No |
| Safety listing | ETL listed to UL 1741 (2nd Ed. with supplement SA) | ETL listed to UL/cUL 458 and CSA C22.2 No. 107.1-01; UL 1741 certificate (ATM) |
| Design | Low-frequency (transformer) | Low-frequency (transformer) |
| Cooling | fan | fan |
| Dimensions | 12 x 8.25 x 16.25 in (30 x 21 x 41 cm) | 13.75 x 12.65 x 8 in (349 x 321 x 203 mm) |
| Weight | 61 lb | 55 lb |
| Warranty | 5 years | 3 years |