MEAN WELL NTS-300-248UN converts 48 VDC nominal battery input to true sine wave AC, with 300 W continuous output. Its factory setting is 230 VAC / 50 Hz with the Universal outlet configuration.
Product Datasheet
Download MEAN WELL NTS-300 Datasheet (PDF)
The NTS-300 section is on PDF pages 9, 10, 11, 12, 13, 14, 15, 16. Refer to the complete mechanical drawings and notes when planning installation.
Model and Configuration
| Complete model |
NTS-300-248UN |
| Series |
NTS-300 |
| Product function |
Off-grid true sine wave DC/AC power inverter |
| Construction |
Enclosed type with AC outlet |
| Model code meaning |
2 = 200/220/230/240 VAC output group; 48 = 48 VDC nominal input; UN = Universal outlet |
Select the DC input voltage, AC output setting and load requirements together. This product converts battery DC to AC for off-grid loads.
AC Output Ratings
| Continuous output power |
300 W |
| Overrated output power, 3 minutes |
345 W |
| Peak output power, 10 seconds |
450 W |
| Surge output power, 30 cycles |
600 W |
| Default AC output voltage |
230 VAC |
| Selectable AC output voltages |
200 / 220 / 230 / 240 VAC |
| Default output frequency |
50 Hz |
| Frequency accuracy / selection |
±0.1 Hz / selectable 50 or 60 Hz |
| Output waveform |
True sine wave; THD <3% |
| AC voltage regulation |
±3.0% at rated output voltage |
Continuous, three-minute, ten-second and 30-cycle limits are separate operating ratings; the short-duration values are not continuous output ratings. Apply both the input-voltage and ambient-temperature limits.
DC Input and Efficiency
| Nominal DC input voltage |
48 VDC |
| Typical DC input range |
40–66 VDC |
| Typical DC input current |
8 A |
| Typical efficiency |
93% |
| Typical no-load power, non-saving mode |
12 W |
| Typical no-load power, saving mode |
1.5 W |
| Off-mode current draw |
≤1 mA |
| Internal pre-start setup time |
8 s |
| Battery types |
Lead-acid or Li-ion |
Efficiency, AC regulation and THD use a 300 W linear test load and 50 VDC input. Unless otherwise specified, other parameters are measured at rated load, 25°C ambient and factory settings.
Saving mode is disabled by default. When enabled, automatic load detection changes to saving mode at an AC load of 10 W or less.
Protection and Battery Thresholds
| Low-voltage alarm |
44 ±1 VDC |
| Low-voltage shutdown |
40 ±1 VDC |
| Low-voltage restart |
50 ±1 VDC |
| High-voltage alarm |
62 ±1 VDC |
| High-voltage shutdown |
66 ±1 VDC |
| High-voltage restart |
60 ±1 VDC |
| Internal fuse |
2 × 10 A |
| Reverse-polarity protection |
Internal fuse opens |
| Typical overload timing |
105–115% load for 180 s; 115–150% load for 10 s |
| Overload / short-circuit recovery |
Output voltage shuts down; re-power on to recover |
| Overtemperature recovery |
Output voltage shuts down; re-power on to recover |
Low-voltage disconnection helps prevent excessive battery discharge. Keep the input polarity and battery operating range within the model requirements.
DIP Switches and Remote Control
| SW1 / SW2 voltage selection |
OFF/OFF: 200 VAC; OFF/ON: 220 VAC; ON/OFF: 230 VAC; ON/ON: 240 VAC |
| SW3 frequency selection |
ON: 50 Hz; OFF: 60 Hz |
| SW4 saving-mode selection |
ON: saving mode; OFF: non-saving mode |
| Dry-contact remote ON/OFF |
Open contact: inverter ON; shorted contact: inverter OFF |
The dry-contact connection uses the two remote-control pins. It is distinct from any serial communication interface.
Indicators and Diagnostics
| Status indicator |
Flashing green: system check; steady green: inverter OK; steady orange: remote OFF; flashing orange: saving mode; red: abnormal status |
| DC input indicator |
Green: 50–62 VDC; orange: 44–50 VDC; red: below 44 or above 62 VDC |
| Load indicator |
Green: below 40%; orange: 40–80%; red: above 80% load |
With steady red Status: flashing Load and DC Input OFF indicates overload or an AC short; flashing DC Input and Load OFF indicates abnormal DC voltage; both DC Input and Load flashing indicate overtemperature or fan-lock status. Flashing Status with both other indicators OFF indicates inverter failure.
NTS-300 is fanless; the operating-temperature limit still applies.
Cooling and Operating Limits
| Cooling method |
Fanless, natural convection |
| Working ambient range |
-25 to 65°C, with derating |
| Horizontal thermal-curve anchors |
-25°C: 100%; 40°C: 100%; 50°C: 80%; 60°C: 50%; 65°C: 40% |
| Input-voltage load curve |
40 VDC: 80%; 42–66 VDC: 100% |
Use the more restrictive input-voltage and temperature limit together. The curves are specified for horizontal installation.
Environment and Isolation
| Operating humidity |
20–90% RH, non-condensing |
| Storage temperature and humidity |
-30 to +70°C; 10–95% RH, non-condensing |
| Vibration |
10–500 Hz, 3G; 10 minutes per cycle; 60 minutes along each X, Y and Z axis |
| DC input to AC output withstand |
3.0 kVAC |
| AC output to frame ground withstand |
1.5 kVAC |
Outlet and Wiring
| Installed AC socket type |
UN / Universal |
| DC input and ground connections |
Marked + and - battery input terminals and a chassis bonding lug |
| R.C. remote connector |
JST B-XH or equivalent; mating housing JST XHP; terminal JST SXH-001T or equivalent |
| R.C. pin connection |
Pins 1 and 2 open: ON; pins 1 and 2 short: OFF |
Select the full mating housing for the shown circuit count and wire size. Follow the unit markings for DC polarity and the chassis bond.
Optional Carry Handle
| Carry-handle order name |
Carry Handle |
| Handle-kit contents |
1 handle, 4 foot pads and 2 screws |
| Handle supply condition |
Order the inverter and Carry Handle separately |
Dimensions, Installation and Reliability
| Overall dimensions, L × W × H |
210 × 130 × 55 mm |
| Drawing tolerance |
±1 mm |
| Reference unit mass |
1300 g |
| Coating |
Conformal coating |
| MTBF, Telcordia SR/TR-332 |
845.6 thousand hours minimum |
| MTBF, MIL-HDBK-217F |
85.3 thousand hours minimum at 25°C |
| Manufacturer warranty listed |
3 years |
| Mounting slots |
120 × 119 mm center spans; slot drawing labels 7 mm width and 9 mm depth |
The unit mass is the per-unit PACKING reference from the catalogue; it is not a measured net mass or a carton-weight average.
Use the mechanical drawing for the mounting locations, connector orientation and airflow. Keep ventilation clear and complete the final installation checks for the equipment.
Safety, EMC and Application
| Model safety scope |
E13; EAC TP TC 004 |
| Certificate marks for this variant |
E13, EAC |
| Radiated emissions |
Type-UN is excluded from the listed FCC / BS EN/EN55032 radiated-emission scope |
| Harmonic current / voltage flicker |
BS EN/EN61000-3-2 / BS EN/EN61000-3-3 |
| EMC immunity framework |
BS EN/EN55024; BS EN/EN55035 |
| ESD immunity |
8 kV air, Level 3; 4 kV contact, Level 2; BS EN/EN61000-4-2 |
| Radiated RF immunity |
3 V/m, Level 2; BS EN/EN61000-4-3 |
| Magnetic-field immunity |
1 A/m, Level 1; BS EN/EN61000-4-8 |
The final equipment must be checked again for compliance with the applicable EMC requirements.
Typical applications include home and office appliances, portable tools, vehicles, yachts and off-grid systems. The marine and vehicle examples show a separate battery charger, battery bank and inverter; these external items are selected and supplied separately.
