MEAN WELL NTS-250P-124 converts 24 VDC nominal battery input to true sine wave AC, with 250 W continuous output. Its factory setting is 110 VAC / 60 Hz in a built-in PCB format.
Product Datasheet
Download MEAN WELL NTS-250P Datasheet (PDF)
The NTS-250P section is on PDF pages 1, 2, 3, 4, 5, 6, 7, 8. Refer to the complete mechanical drawings and notes when planning installation.
Model and Configuration
| Complete model |
NTS-250P-124 |
| Series |
NTS-250P |
| Product function |
Off-grid true sine wave DC/AC power inverter |
| Construction |
Built-in PCB type |
| Model code meaning |
1 = 100/110/115/120 VAC output group; 24 = 24 VDC nominal input; P = built-in PCB version |
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 |
250 W |
| Overrated output power, 3 minutes |
287.5 W |
| Peak output power, 10 seconds |
375 W |
| Surge output power, 30 cycles |
500 W |
| Default AC output voltage |
110 VAC |
| Selectable AC output voltages |
100 / 110 / 115 / 120 VAC |
| Default output frequency |
60 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 |
24 VDC |
| Typical DC input range |
20–33 VDC |
| Typical DC input current |
13 A |
| Typical efficiency |
91% |
| Typical no-load power, non-saving mode |
10 W |
| Typical no-load power, saving mode |
1.3 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 250 W linear test load and 25 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.
The off-mode current figure is specified with the battery-to-DC input connection disconnected.
Protection and Battery Thresholds
| Low-voltage alarm |
22 ±0.5 VDC |
| Low-voltage shutdown |
20 ±0.5 VDC |
| Low-voltage restart |
25 ±0.5 VDC |
| High-voltage alarm |
31 ±0.5 VDC |
| High-voltage shutdown |
33 ±0.5 VDC |
| High-voltage restart |
30 ±0.5 VDC |
| Internal fuse |
1 × 30 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: 100 VAC; OFF/ON: 110 VAC; ON/OFF: 115 VAC; ON/ON: 120 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: 25–31 VDC; orange: 22–25 VDC; red: below 22 or above 31 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.
This board uses an external fan where the cooling curve requires one.
Cooling and Operating Limits
| Cooling method |
Natural convection with derating to 60°C; 10 CFM forced air for the plotted 60–70°C region |
| Working ambient range |
-20 to 70°C, with derating |
| Horizontal thermal-curve anchors |
-20°C: 100%; 40°C: 100%; 50°C: 80%; 60°C: 50%; 70°C: 40% |
| Input-voltage load curve |
20 VDC: 80%; 21–33 VDC: 100% |
Use the more restrictive input-voltage and temperature limit together. The curves are specified for horizontal installation.
The 60–70°C part of the curve requires 10 CFM forced air; natural convection applies to the lower-temperature portion. Keep the illustrated fan airflow directed from the DC input side toward the board.
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 |
PCB Wiring and Mating Connectors
| TB1 DC input |
Red: +V; black: -V. Anderson 1327 / 1327G6 mating housings; terminal 261G2-LPBK, or equivalents |
| CN500 AC output pinout |
1: FG; 2 and 3: NC; 4: AC/N; 5: NC; 6: AC/L |
| CN500 connector and mating parts |
JST B6P-VH; mating housing JST VHR; terminal JST SVH-21T-P1.1, or equivalents |
| CN301 remote-control connection |
JST S2B-XH-A; mating housing JST XHP; terminal JST SXH-001T, or equivalents. Pins 1 and 2 open: ON; short: OFF |
| CN50 communicating pinout |
1: Signal GND; 2: UART-RX; 3: UART-TX |
| CN50 connector and mating parts |
CHYAO SHIUN JS-100R-03; mating housing CHYAO SHIUNN JS-2001; terminal CHYAO SHIUNN JS-2001-TX, or equivalents |
| CN100 fan connection |
1: fan +V; 2: fan -V; 3: PWM fan-speed control. Fan supply: 12 V / 0.4 A maximum |
| CN100 connector and mating parts |
JST B3B-XH-A; mating housing JST XHP; terminal JST SXH-001T, or equivalents |
| DC input contact configuration |
4-pin arrangement for 12 V input; 2-pin arrangement for 24 V or 48 V input |
The UART Tx/Rx interface supports inverter-status monitoring. Select the full mating housing for the circuit count and wire assembly shown in the mechanical drawing.
Included Wires and Cooling Accessories
| Included CN50 / CN100 mating wires |
2 pieces per model; 50 mm, UL1007, 22 AWG |
| Included CN301 mating wire |
1 piece per model; 50 mm, UL1007, 22 AWG |
| Suggested external fan |
CCHV CHT4012BH-W20D 4020B |
| Illustrated external fan position |
5 cm from the DC input side, blowing toward the PCB; 10 CFM where required by the derating curve |
The fan is a suggested external component. The standard accessory list specifies the mating wires; it does not list a supplied fan.
Dimensions, Installation and Reliability
| Overall dimensions, L × W × H |
186 × 100.5 × 34 mm |
| Drawing tolerance |
±1 mm |
| Reference unit mass |
870 g |
| Coating |
Conformal coating |
| MTBF, Telcordia SR/TR-332 |
836.9 thousand hours minimum |
| MTBF, MIL-HDBK-217F |
84 thousand hours minimum at 25°C |
| Manufacturer warranty listed |
3 years |
| PCB mounting holes |
Three Ø3.5 mm holes marked M3 and one Ø5.5 mm hole marked M5; follow the drawing for the 174.6 × 88.6 mm center spans |
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 |
CB IEC62368-1 second edition; CSA/UL62368-1 third edition |
| Certificate marks for this variant |
CB, cCSAus, FCC |
| Radiated emissions |
FCC Class A |
| 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 |
15 kV air and 8 kV contact, Level 4; BS EN/EN61000-4-2 |
| Radiated RF immunity |
10 V/m, Level 3; BS EN/EN61000-4-3 |
| Magnetic-field immunity |
30 A/m, Level 4; BS EN/EN61000-4-8 |
The final equipment must be checked again for compliance with the applicable EMC requirements.
Typical applications include built-in off-grid equipment, security systems, mobile carts, portable tools and battery-powered AC loads. The application drawing does not itself establish a medical-equipment approval.
