Samlex NTX-400-12
#17 in Up to 1,000 WFull review
For a van or truck cab that needs listed power for electronics and a USB charger.
The Samlex NTX-400-12 is the better 12V inverter overall, rated 3.1 to 2.9. The Samlex NTX-400-12 leads on efficiency. The Xantrex PROwatt SW 600 wins on idle draw and features.
Xantrex PROwatt SW 600
#20 in Up to 1,000 WFull review
A small, listed inverter for CPAPs, laptops and TVs in a trailer or van. You pay a premium for the listing and Xantrex support.
Amazon $275.43$275.43
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 Samlex NTX-400-12 for efficiency (91% peak efficiency (maker rating) vs 90% peak efficiency (maker rating)).
- Choose the Xantrex PROwatt SW 600 for idle draw (0.6 A idle (about 7.2 W) with nothing plugged in vs 0.8 A idle (about 9.6 W) with nothing plugged in) and features (optional remote, display; no app vs outlets only).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every up to 1,000 W 12V inverter; a clear win is highlighted. How we rank explains each one.
| Factor weight | Samlex NTX-400-12 | Xantrex PROwatt SW 600 |
|---|---|---|
| Overall rating | 3.1/5 | 2.9/5 |
| Value 30% | 50 no current price (neutral score used) | 19 $0.51 per continuous watt |
| Idle draw 15% | 27 0.8 A idle (about 9.6 W) with nothing plugged in | 53 0.6 A idle (about 7.2 W) with nothing plugged in |
| Safety listing 15% | 100 Intertek ETL listed; conforms to UL 458 and certified to CSA C22.2 No. 107.1 | 100 ETL listed to CSA C22.2 No. 107.1 and UL 458 with marine supplement |
| Warranty 15% | 25 2-year warranty | 25 2-year warranty |
| Features 15% | 0 outlets only | 22 optional remote, display; no app |
| Efficiency 10% | 67 91% peak efficiency (maker rating) | 56 90% peak efficiency (maker rating) |
Specifications
| Samlex NTX-400-12 | Xantrex PROwatt SW 600 | |
|---|---|---|
| Output | ||
| Type | Pure sine wave inverter | Pure sine wave inverter |
| Continuous power | 400 W | 540 W |
| Surge power | 800 W for 1 s | 1,200 W |
| DC input range | 10.5 to 16.3 V | 10.5 to 15.5 V |
| Idle draw | 0.8 A (9.6 W) | 0.6 A (7.2 W) |
| Peak efficiency | 91% | 90% |
| Connections | ||
| AC outlets | 2 | 2 |
| GFCI outlets | No | Yes |
| Hardwire terminal | No | No |
| USB ports | 1 | 1 |
| Transfer switch | No | No |
| Parallel units | No | No |
| Control and build | ||
| Remote | No | Optional extra |
| App | No | No |
| Display | No | Yes |
| Safety listing | Intertek ETL listed; conforms to UL 458 and certified to CSA C22.2 No. 107.1 | ETL listed to CSA C22.2 No. 107.1 and UL 458 with marine supplement |
| Cooling | load-controlled fan | load-controlled fan |
| Dimensions | 155 x 225 x 59 mm (6.10 x 8.86 x 2.32 in) | 12.2 x 8.7 x 3.5 in (310 x 220 x 89 mm) |
| Weight | 2 lb | 6.5 lb |
| Warranty | 2 years | 2 years |
| Released | - | 2009-10 |