The MEAN WELL NPB-750-48 is an intelligent battery charger with a default 57.6 V boost setting, 55.2 V float setting and 11.3 A constant-current setting. Its maximum output power is 759.4 W under the specified output-voltage, input and temperature conditions. The 48 V suffix denotes the voltage class, not the actual charging voltage. It supports two- or three-stage charging, four DIP presets and CANbus control.
Product Datasheet
Download MEAN WELL NPB-750 Datasheet (PDF)
The NPB-750 section is on PDF pages 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54. Refer to the complete mechanical drawings and notes when planning installation.
Charging Output and Battery Selection
| Complete model |
NPB-750-48 |
| Nominal voltage class |
48 V |
| Default boost charge voltage |
57.6 V |
| Default float charge voltage |
55.2 V |
| Maximum charging current |
11.3 A |
| Maximum output power |
759.4 W |
| Default constant-current setting |
11.3 A |
| Programmable boost or float range |
42–80 V |
| Suggested battery capacity |
40–130 Ah |
| Typical battery leakage current |
Less than 1 mA |
| Typical efficiency |
93% |
Efficiency is measured at 67.2 V charging output, with the general catalogue conditions of 230 VAC, rated load and 25°C unless otherwise stated. Maximum power is not the product of the default boost voltage and default CC setting. Apply the output-current, input-voltage and temperature limits together.
The capacity range is a recommendation; confirm the battery manufacturer’s allowable charging current and voltage. Suitable battery types include flooded, gel and AGM lead-acid, and lithium-ion types described as lithium iron and lithium manganese. Battery-specific charger settings or modification may be needed. A voltage-class match alone does not establish compatibility; auto-ranging has the additional lithium-and-BMS restriction below.
Two- and Three-Stage Charging
| DIP switch 1 |
OFF: three-stage charging, factory default; ON: two-stage charging |
| DIP 2 OFF / DIP 3 OFF |
Default programmable: 57.6 V boost / 55.2 V float |
| DIP 2 ON / DIP 3 OFF |
Gel: 56 V boost / 54.4 V float |
| DIP 2 OFF / DIP 3 ON |
Flooded: 56.8 V boost / 53.6 V float |
| DIP 2 ON / DIP 3 ON |
AGM / LiFePO4: 58.4 V boost / 56 V float |
The default CC value for all four preset curves is 11.3 A. Stage 1 holds constant current while battery voltage rises to Vboost; stage 2 holds constant voltage while current tapers. In two-stage operation, charging stops at the taper-current threshold. In three-stage operation it changes to the float voltage. The default threshold is 10% of CC; SBP-001 or CANbus can set it from 2% to 30%. Float values apply only to the three-stage profile.
The default profile is programmable; the other three preset profiles are selected by the DIP switches. Choose a profile suitable for the particular battery rather than relying only on a chemistry label.
Auto-Ranging Mode and Current Adjustment
Auto-ranging is OFF by factory default. It may be used only with lithium batteries equipped with a battery-management system (BMS), and is prohibited for non-lithium batteries. In this mode, the charger detects the connected battery voltage and does not start until an appropriate voltage is detected. The MCU adjusts voltage automatically; there is no front-panel voltage-adjustment potentiometer.
The Io Adj potentiometer adjusts charging current from 50% to 100% only while auto-ranging is active. It cannot adjust current in non-auto-ranging mode. All programmed and automatically selected values must remain within the model’s voltage and current limits.
To enable auto-ranging: set all DIP switches OFF; apply AC and switch on with remote control OFF. Within 15 seconds, move all DIP switches ON and then back OFF. Three green LED flashes confirm the change. Restart using AC input or the AC-side power switch, then fit the jumper between CN71 pins 7 and 8.
To return to non-auto-ranging: set all DIP switches ON before applying AC; apply AC with remote control OFF. Within 15 seconds, move all switches OFF and then back ON. Three green flashes confirm success. Remote-enable the charger to return to the factory non-auto-ranging setting.
Input and Power Factor
| Input voltage range |
90–264 VAC or 127–370 VDC |
| AC frequency |
47–63 Hz |
| Typical AC input current |
8.7 A at 115 VAC; 4 A at 230 VAC |
| Typical power factor |
PF >0.98 at 115 VAC; >0.95 at 230 VAC, at full load |
| Typical cold-start inrush |
50 A at 230 VAC |
| Input leakage current |
Less than 1 mA at 240 VAC |
Active inrush-current limiting and PFC are shown in the block diagram; the stated PFC and PWM switching frequencies are 80 kHz and 60 kHz. Use the AC inlet, switch and protective-earth arrangement shown in the mechanical drawing. Low-input operation requires the derating below.
Cooling, Output Limits and Derating
| Cooling |
Internal DC fan with speed controlled by internal temperature |
| Horizontal temperature curve |
100% power through +50°C; reduce to 50% at +70°C |
| Low-temperature condition |
The −30 to −25°C region is specified for 230 VAC input only |
| AC input curve at 60 Hz |
90 VAC: 90%; 100 VAC: 100%; 264 VAC: 100% |
| Output-voltage/current curve |
100% current from 42 to 67.2 V; reduce to 80% at 80 V |
Apply the complete curves and the maximum power limit together; full current is not available throughout the entire programming range. The AC input curve does not establish an additional DC-input derating curve. Keep inlet and exhaust airflow clear and use the stated horizontal installation orientation.
Automatic thermal derating also operates during two-/three-stage charging and CANbus control. Its functional diagram defines T1 as the maximum ambient temperature at 100% output current, and T2 as T1 + 5°C, where current reaches 50%. The transition is explicitly non-linear; these symbols do not specify an extra absolute-temperature operating allowance.
For this fan-cooled charger above 2000 m, reduce the permissible ambient temperature by 5°C for each additional 1000 m. This derating instruction does not specify an unrestricted maximum operating altitude.
Protection and Battery Temperature Sensing
| Short circuit |
Constant-current limiting, then output shutdown after 5 seconds; re-power to recover |
| Overvoltage range |
82–100 V; output shutdown and latch-off; re-power to recover |
| Reverse battery polarity |
Internal reverse-polarity detection, no damage; remove the fault and re-power |
| Overtemperature |
Output shutdown; automatic recovery after temperature falls |
| Battery undervoltage |
Listed protection feature; no numeric cutoff voltage is specified |
| Temperature compensation |
5 kΩ NTC sensor; lead-acid batteries, three-stage charging only, 0–40°C |
The short-circuit mechanism is specified for a short circuit occurring after charger turn-on. MCU-controlled dynamic overvoltage protection is approximately 125% of Vboost in CC/CV stages, or 125% of Vfloat in the float stage; these protection values are not battery charging settings.
The supplied NTC sensor connects to CN71 pin 13 RTH+ and pin 14 RTH− and compensates charging voltage for lead-acid battery temperature. The charger operates normally if the sensor is not used. No numerical compensation slope is specified on these pages.
CN71 Control Connector and Status Signals
| Connector and mating housing |
Charger: HRS DF11-14DP; mating housing: HRS DF11-14DS, or equivalents |
| Contact family |
HRS DF11-**SC or equivalent; select the complete suffix for the wire and assembly |
| Pins 1–4 |
1: A1; 2: A0; 3: +3.3V; 4: GND (Signal) |
| Pins 5–8 |
5: Battery Full; 6: Charger OK; 7: Remote ON-OFF; 8: +12Vaux |
| Pins 9–12 |
9 and 10: GND-AUX; 11: CANH; 12: CANL |
| Pins 13–14 |
13: NTC (RTH+); 14: NTC (RTH−) |
A1 and A0 are CANbus address lines, and +3.3V is referenced to pin 4 GND (Signal); these address signals are non-isolated. The control/status and CAN signals use GND-AUX on pins 9 and 10, whose return is isolated from the +V and −V output terminals. Do not substitute the power return or address-signal ground for the specified reference.
Charger OK (pin 6) and Battery Full (pin 5) are TTL outputs referenced to GND-AUX, with maximum sourcing current 10 mA each and output-only use. A high level of 4.5–5.5 V means normal charger operation or battery full, respectively. A low level of −0.5 to +0.5 V means failure/protection for Charger OK, or charging for Battery Full.
Remote ON/OFF uses a dry contact between pin 7 and +12Vaux pin 8. Shorted is ON (10.8–13.2 V at pin 7); open is OFF (−0.5 to +0.5 V). Maximum remote input is 13.2 V. The charger is supplied with pins 7 and 8 shorted by a connector. Pin 8 is controlled by remote ON/OFF; no external auxiliary-load current rating is specified.
Status LED: green indicates float or full; orange indicates CC/CV charging; flashing orange indicates auto-ranging. Red indicates OTP, OVP, short circuit, reversed battery polarity or charging timeout. Flashing red indicates an internal temperature of 95°C while the unit is still operating without entering OTP; an alarm is sent over CANbus.
CANbus Control and Monitoring
The built-in CANbus 2.0B interface controls, sets and monitors output voltage, charging current, charging curves, internal temperature and DC output ON/OFF. Connect CANH to CN71 pin 11, CANL to pin 12 and the specified reference to pins 9/10. Use the manufacturer’s protocol for addressing, data encoding and command operation; the presence of a PMBus branch on the programmer cable does not establish PMBus support for this charger.
Core commands: 0x0000 OPERATION (R/W, 1 byte); 0x0020 VOUT_SET and 0x0030 IOUT_SET (R/W, 2 bytes, factor 0.01); 0x0040 FAULT_STATUS (read, 2 bytes); 0x0060 READ_VOUT and 0x0061 READ_IOUT (read, 2 bytes, factor 0.01); 0x0062 READ_TEMPERATURE_1 (read, 2 bytes, factor 0.1). 0x0050 READ_VIN is not supported by NPB-750.
Identification commands: 0x0080/0x0081 MFR_ID_B0B5/B6B11, 0x0082/0x0083 MFR_MODEL_B0B5/B6B11 and 0x0084 MFR_REVISION_B0B5 are read-only, 6 bytes each. 0x0085 MFR_LOCATION_B0B2 is R/W, 3 bytes; 0x0086 MFR_DATE_B0B5 and 0x0087/0x0088 MFR_SERIAL_B0B5/B6B11 are R/W, 6 bytes each.
Charging commands are 2 bytes each: 0x00B0 CURVE_CC, 0x00B1 CURVE_CV, 0x00B2 CURVE_FV and 0x00B3 CURVE_TC are R/W with factor 0.01; 0x00B4 CURVE_CONFIG and 0x00B5/0x00B6/0x00B7 CURVE_CC_TIMEOUT/CV_TIMEOUT/FV_TIMEOUT are R/W. 0x00B8 CHG_STATUS is read-only; 0x00B9 CHG_RST_VBAT is R/W and sets the restart-voltage point after full charge. 0x00C0 SCALING_FACTOR and 0x00C1 SYSTEM_STATUS are read-only, while 0x00C2 SYSTEM_CONFIG is R/W (all 2 bytes).
Programming and Included or Optional Accessories
| SBP-001 smart programmer |
Optional; sold separately from the charger; used with a personal computer |
| SBP#1 communication cable |
Charger 14-pin connector to the programmer 10-pin connector through the CANbus branch |
| Standard NTC sensor wire |
Quantity 1; UL2468 24×2C; drawing shows 50 mm wire and 7 mm stripped ends |
| Standard remote-control mating wire |
Quantity 1; HRS DF11-14DS or equivalent, UL1007 28 AWG; 50 mm wire, 7 mm stripped ends and a 10 mm loop marking |
| Optional Carry Handle |
Ordered separately; listed kit contains one handle, four foot pads and two screws |
For SBP-001 programming, set DIP switches 2 and 3 OFF and remove the CN71 pin 7/8 jumper. Connect SBP#1 between the charger and programmer, and connect the PC Type-A USB port to the programmer Mini USB port. The software sets CC, taper current, CV, float voltage, stage selection and charging timeouts. Refer to the actual cable drawing on PDF page 46 for orientation and wiring.
The SBP#1 drawing marks HRS DF11-14DP at the charger interface and HRS DF11-10DP at the programmer interface, or equivalents, with UL1007 28 AWG wire and 180 mm overall dimension. The programmer’s 10-pin assignments are 1 UART_RX, 2 UART_TX, 3 PMBUS_D, 4 PMBUS_C, 5 CAN_H, 6 CAN_L, 7 5V, 8 GND, 9 3.3V and 10 GND. Follow the CANbus branch shown for this charger.
The NTC connection diagram permits customer extension between the supplied mating wire and battery sensor; no maximum extension length is specified. The Carry Handle drawing marks the two screws M4*2 without a separate length specification. Confirm the correct handle kit and complete contact suffix when ordering; do not infer a different accessory model code or included programmer.
Mechanical Installation
| Body dimensions |
230 × 158 × 67 mm (L × W × H) |
| Case drawing |
Case No. 285A; dimensional tolerance ±1 mm |
| Output terminal projection |
19.5 mm beyond the indicated body face |
| Catalogue unit weight |
1.84 kg (1840 g), catalogue packing reference per unit; not a measured net or shipping weight |
The flange slot centres are 145 mm apart along the length, with the indicated right-hand slot 42.5 mm from the body edge. The top drawing marks 144 mm between the handle attachment positions. The front view has +V on the left and −V on the right, with 36 mm between the output terminals. The drawing marks 138 mm body width within the 158 mm overall width.
The mechanical drawing on PDF page 52 shows the AC inlet, switch, fan airflow direction, DC terminal polarity, status LED, DIP switches, Io Adj and CN71. Reserve space for connectors, cables, terminal projections and ventilation. No output-terminal tightening torque or power-cable gauge is specified on these pages; select wiring and tightening requirements for the supplied terminal assembly.
Environment, Safety and Reliability
| Working humidity |
20–95% RH, non-condensing |
| Storage conditions |
−40 to +85°C; 10–95% RH, non-condensing |
| Temperature coefficient |
±0.05%/°C over 0–50°C |
| Vibration |
10–500 Hz, 2 G; 10 minutes per cycle; 60 minutes along each X, Y and Z axis |
| Dielectric withstand |
Input–output: 3 kVAC; input–FG: 2 kVAC; output–FG: 0.5 kVAC |
| Insulation resistance |
100 MΩ for input–output, input–FG and output–FG, at 500 VDC, 25°C and 70% RH |
Safety approvals listed: CB IEC 62368-1 and IEC 60335-1/2-29; Dekra BS EN/EN 62368-1 and BS EN/EN 60335-1/2-29; UL 62368-1; EAC TP TC 004. These charger approvals do not automatically certify the complete battery-powered equipment.
BS EN/EN 55032 (CISPR32) and BS EN/EN 55014-1: conducted Class B. Radiated Class B requires an additional 13 × 26 × 30 NiZn magnetic clasp or ring on the output line; without it, radiated performance is Class A. Select the applicable magnetic component and installation for the final equipment. Harmonic current: BS EN/EN 61000-3-2 Class A; voltage flicker: BS EN/EN 61000-3-3. The charger is a component for installation in final equipment, whose EMC compliance must be reconfirmed.
Immunity: BS EN/EN 61000-4-2 ESD, 8 kV air (level 3) and 4 kV contact (level 2); 4-3 radiated RF, 3 V/m (level 2); 4-4 EFT/burst, 1 kV (level 2); 4-5 surge, 1 kV line–line and 2 kV line–earth; 4-6 conducted RF, 3 Vrms (level 2); 4-8 magnetic field, 1 A/m (level 1). Under 4-11, the table specifies >95% dip for 0.5 periods, 30% dip for 25 periods and >95% interruption for 250 periods.
Calculated MTBF: 682.9 thousand hours minimum using Telcordia SR-332, or 67.7 thousand hours minimum using MIL-HDBK-217F at 25°C. These calculations are not a guaranteed service life. The manufacturer’s catalogue lists a three-year warranty.
