The MEAN WELL ENC-120-24 is a fanless programmable desktop battery charger for the 24 V nominal battery class. Its default three-stage profile uses 28.8 V boost charging, 27.6 V float charging and 4 A constant current, with a rated output power of 115.2 W. Select the charging curve and temperature compensation to suit the battery.
Product Datasheet
Download MEAN WELL ENC-120 Datasheet (PDF)
The ENC-120 section is on PDF pages 17, 18, 19, 20, 21, 22. Refer to the complete mechanical drawings and notes when planning installation.
Model and Charging Output
| Complete model |
ENC-120-24 |
| Model code |
ENC-120 identifies the programmable desktop charger series; 24 identifies the nominal battery-voltage class. |
| Default boost charge voltage |
28.8 V |
| Default float charge voltage |
27.6 V |
| Rated charging current |
4 A |
| Rated output power |
115.2 W |
| Programmable charge-voltage range |
18–30 V for Vboost or Vfloat, using SBP-001. |
| Suggested battery capacity |
15–40 Ah |
| Typical battery leakage current |
Less than 1 mA |
| Typical efficiency |
90% |
The 24 V model designation is a nominal battery class, not a fixed charging-output voltage. Select a battery pack whose charge limits match the actual boost and float settings, the 4 A default current and the required temperature compensation.
The catalogue identifies flooded, gel and AGM lead-acid batteries, and lithium-ion types described as lithium iron and lithium manganese. Compatibility depends on the complete battery specification and its protection requirements; consult the battery manufacturer and MEAN WELL about settings and maximum permissible charging current. The suggested capacity range does not replace that check.
Three-Stage Charging and Curve Selection
| DIP 1 OFF / DIP 2 OFF |
Default programmable curve: Vboost 28.8 V; Vfloat 27.6 V; default CC 4 A. |
| DIP 1 ON / DIP 2 OFF |
Predefined gel curve: Vboost 28 V; Vfloat 27.2 V. |
| DIP 1 OFF / DIP 2 ON |
Predefined flooded-battery curve: Vboost 28.4 V; Vfloat 26.8 V. |
| DIP 1 ON / DIP 2 ON |
Predefined AGM curve: Vboost 29 V; Vfloat 27 V. |
Stage 1 charges at constant current while voltage rises. Stage 2 holds Vboost and allows charging current to fall. The default diagram marks the transition to stage 3 at 10% of the selected CC level; stage 3 then holds the lower Vfloat voltage.
The status LED is orange during stages 1 and 2, and green during the float stage. Green indicates the charger's stage, not a universal state-of-charge measurement for every battery chemistry.
The embedded curve table specifies 4 A as the default CC setting for this model. The two-position DIP switch selects the default programmable curve or one of the three predefined battery curves shown above.
Changing the default charging-curve parameters requires the MEAN WELL SBP-001 smart battery charging programmer and a personal computer. These programming tools are not listed as supplied charger accessories. Select the charging profile for the battery before operation; the programmable voltage range is not a guarantee of suitability for every battery within it.
AC/DC Input
| Input voltage |
90–264 VAC or 127–370 VDC; apply low-input derating. |
| Input frequency |
47–63 Hz |
| Typical power factor |
PF >0.98 at 115 VAC; PF >0.95 at 230 VAC, at full load. |
| Typical AC input current |
1.25 A at 115 VAC; 0.63 A at 230 VAC. |
| Typical cold-start inrush |
65 A at 230 VAC |
| Input leakage current |
Less than 3.5 mA at 240 VAC |
Active power factor correction is built in. Use the grounded AC inlet and protective-earth connection shown in the mechanical and block diagrams, and keep access to the power switch and input connection.
Unless otherwise stated, the published specifications are measured at 230 VAC, rated load and 25°C ambient.
Protection and Battery Temperature Compensation
| Short circuit |
Output shuts down; re-power to recover. This specification applies to a short circuit occurring after the charger is turned on. |
| Specified overvoltage range |
31–36.5 V; output shuts down and latches off, requiring re-powering to recover. |
| Dynamic overvoltage control |
MCU protection is approximately 115% of Vboost during constant-current and constant-voltage stages, and approximately 115% of Vfloat during the float stage. |
| Battery reverse polarity |
Protection by an internal fuse. |
| Overtemperature |
Output shuts down and recovers automatically after temperature falls. |
| Battery undervoltage |
Battery undervoltage protection is included in the feature list. |
| Temperature compensation |
Built-in NTC temperature compensation; connect the sensor through RTH+ and RTH− at CN31. |
Match battery polarity and the selected charge curve before connection. The programmed charge voltage and the stage-dependent protection function must be considered together; the overvoltage range is not an adjustable normal charging range.
Temperature, Input Derating and Environment
| Working temperature |
−30 to +70°C, subject to derating. |
| Horizontal thermal curve |
100% load from −30 to +50°C; reduce linearly to 60% at +70°C. |
| AC input curve at 60 Hz |
90% load at 90 VAC, rising to 100% at 100 VAC; 100% from 100 to 264 VAC. |
| 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. |
Cooling is by free-air convection without a fan. Apply the horizontal-installation curve and the low-input curve together, keeping ventilation openings unobstructed. The published AC curve does not define a separate DC-input curve.
For this fanless charger, reduce allowable ambient temperature by 3.5°C per additional 1000 m above 2000 m. This adjustment does not establish an unrestricted maximum operating altitude.
Dimensions and Installation
| Body dimensions |
192 × 178 × 45.5 mm (L × W × H); case 252. |
| Drawing tolerance |
±1 mm unless otherwise indicated in the mechanical drawing. |
| Catalogue unit weight |
0.98 kg (980 g), catalogue packing reference per unit; not a measured net or shipping weight. |
PDF page 21 shows the inlet, switch, output terminal block, indicator, DIP switch and six-pin programming/sensor connector. Follow the complete drawing for orientation and clearance.
Output Wiring and CN31 Interface
| TB1 output terminals |
Pins 1 and 2: +V; pins 3 and 4: −V. |
| TB1 conductor size |
0.5–4.0 mm² (12–20 AWG). |
| TB1 preparation and torque |
Recommended stripped length: 9 mm. Screw torque: 4.0 lb-in (0.4–0.5 N·m). |
| CN31 connector |
HRS DF11-6DP-2DS or equivalent. |
| CN31 pin 1 |
Prog-+3.3V |
| CN31 pin 2 |
Prog-GND |
| CN31 pin 3 |
Prog-RX |
| CN31 pin 4 |
Prog-TX |
| CN31 pin 5 |
RTH+ |
| CN31 pin 6 |
RTH− |
| CN31 mating housing |
HRS DF11-6DS or equivalent. |
| CN31 contact reference |
HRS DF11-**SC or equivalent; select the complete contact variant for the intended wire assembly. |
Use the connector-view numbering in the mechanical drawing. The programming supply and RX/TX pins serve the stated programming interface; do not use them as a general-purpose auxiliary power output.
Programming Equipment and Listed Accessories
| Programming equipment |
SBP-001 smart battery charging programmer plus a personal computer; required for changing the programmable curve. |
| NTC sensor wire |
Quantity 1 in the accessory list. Drawing: UL2468 24 × 2C, 50 mm insulated wire length and 7 mm exposed end. |
| NTC mating wire |
Quantity 1 in the accessory list. Drawing: UL1007 28 AWG, 50 mm insulated wire length and 6 mm exposed end. |
| Sensor-wire connector drawing reference |
HRS DF11-6DP-2DS or equivalent, as identified on the NTC mating-wire drawing. |
The two NTC wires are the accessories identified with quantities in the charger catalogue. The connector and contact references above specify the matching interface parts; additional loose contacts, mains leads, battery leads or programming equipment are not included in that accessory list. Confirm the ordered package contents and the finished cable assembly when procuring replacements.
Safety, EMC and Reliability
| Safety approvals |
IEC 62368-1, UL 62368-1, EAC TP TC 004 and BSMI CNS15598-1 approved; meets BS EN/EN 62368-1. |
| Dielectric withstand |
Input–output: 3 kVAC; input–FG: 2 kVAC; output–FG: 0.5 kVAC. |
| Insulation resistance |
100 MΩ between input/output, input/FG and output/FG; tested at 500 VDC, 25°C and 70% RH. |
| Conducted and radiated emissions |
Class B: BS EN/EN 55032 (CISPR32), FCC Part 15 (CISPR22) and BSMI CNS15936. |
| Harmonics and flicker |
BS EN/EN 61000-3-2 and BS EN/EN 61000-3-3. |
| ESD immunity |
BS EN/EN 61000-4-2: 8 kV air, level 3; 4 kV contact, level 2. |
| Radiated immunity |
BS EN/EN 61000-4-3: 3 V/m, level 2. |
| EFT/burst immunity |
BS EN/EN 61000-4-4: 1 kV, level 2. |
| Surge immunity |
BS EN/EN 61000-4-5: 1 kV line–line, level 2; 2 kV line–earth, level 3. |
| Conducted immunity |
BS EN/EN 61000-4-6: 3 Vrms, level 2. |
| Magnetic-field immunity |
BS EN/EN 61000-4-8: 1 A/m, level 1. |
| Voltage dips and interruptions |
BS EN/EN 61000-4-11: >95% dip for 0.5 periods; 30% dip for 25 periods; >95% interruption for 250 periods. |
| Calculated minimum MTBF |
1726.4 thousand hours, Telcordia SR-332; 206.1 thousand hours, MIL-HDBK-217F at 25°C. |
The immunity framework is BS EN/EN 55024. Although the charger is evaluated as an independent unit, the complete installed equipment still requires confirmation of compliance with the EMC directives.
The catalogue lists a three-year manufacturer warranty. Calculated MTBF is a reliability estimate, not a guaranteed service life.
