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 is the better 48V inverter overall, rated 3.8 to 3.6. The OutBack VFXR3648A leads on safety listing. The Victron Quattro 48/5000 120V wins on value and efficiency. The Victron Quattro 48/5000 120V costs $500.15 less ($1,638.85 vs $2,139).
Victron Quattro 48/5000 120V
For an off-grid home or large boat that switches between grid and generator and needs big motor-starting power. The MultiPlus-II 48/5000 idles lower and has published UL certificates if one AC input is enough.
Amazon $1,785 Backwoods Solar $1,638.85$1,638.85
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 safety listing (ETL listed to UL 1741 (2nd Ed. with supplement SA) vs no UL 458 or UL 1741 listing stated).
- Choose the Victron Quattro 48/5000 120V for value ($0.41 per continuous watt vs $0.59 per continuous watt) and efficiency (95% 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 | Victron Quattro 48/5000 120V |
|---|---|---|
| Overall rating | 3.8/5 | 3.6/5 |
| Value 30% | 32 $0.59 per continuous watt | 60 $0.41 per continuous watt |
| Idle draw 15% | 66 34 W idle with nothing plugged in | 64 35 W idle with nothing plugged in |
| Safety listing 15% | 100 ETL listed to UL 1741 (2nd Ed. with supplement SA) | 0 no UL 458 or UL 1741 listing stated |
| Warranty 15% | 100 5-year warranty | 100 5-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 95% peak efficiency (maker rating) |
Specifications
| OutBack VFXR3648A | Victron Quattro 48/5000 120V | |
|---|---|---|
| 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 | 10,000 W |
| DC input range | 42 to 68 V | 38 to 66 V |
| Idle draw | 34 W (0.7 A at 48 V) | 35 W (0.7 A at 48 V) |
| Power-saving draw | 9 W | 15 W |
| Peak efficiency | 93% | 95% |
| 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 | 100 A |
| Charger | 45 A | 70 A |
| Lithium charge profile | Yes | Yes |
| Parallel units | Yes | Yes |
| 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) | No |
| Design | Low-frequency (transformer) | - |
| Cooling | fan | fan |
| Dimensions | 12 x 8.25 x 16.25 in (30 x 21 x 41 cm) | 444 x 328 x 240 mm (17.5 x 13.0 x 9.6 in) |
| Weight | 61 lb | 66 lb |
| Warranty | 5 years | 5 years |