MEAN WELL DRC-40 Series 40W DIN Rail Power Supply with Battery Charger | DRC-40A / DRC-40B

Overview of MEAN WELL DRC-40 Series

The MEAN WELL DRC-40 Series is a compact 40W AC/DC DIN rail power supply with integrated battery charger and UPS backup function, developed for security systems, access control, alarm systems, emergency lighting, central monitoring and other applications that require continuous DC power during AC mains interruption.
Unlike a conventional DIN rail power supply, the DRC-40 Series combines a primary DC output with a dedicated battery charging output. When AC mains power is available, the unit supplies the connected load while charging the battery. If AC input fails, the battery automatically supplies power to the load, providing a simple DC backup architecture for security and monitoring equipment.
The series accepts a universal 90–264VAC input and also supports 127–370VDC input. Two main models are available: DRC-40A provides 13.8VDC output for 12V battery systems, while DRC-40B provides 27.6VDC output for 24V battery systems. Both models provide approximately 40W rated output power and are designed for compact TS35 DIN rail installation.
For system supervision, the DRC-40 Series includes AC OK and Battery Low alarm signals through TTL open collector outputs on standard models, while relay contact output is available as an optional configuration. These signals allow connected controllers, alarm panels and monitoring systems to detect AC power failure or low battery conditions.
Built-in protection functions include short circuit, overload, overvoltage, battery low cut-off and battery reverse polarity protection by fuse. The series operates by free-air convection over a wide -30°C to +70°C operating temperature range and can be mounted on TS35/7.5 or TS35/15 DIN rail for installation inside control cabinets and security system enclosures.
In industrial and OEM procurement, the series is commonly specified as MEAN WELL DRC-40A, MEAN WELL DRC-40B, 40W DIN rail power supply with battery charger, DIN rail UPS power supply, 12V battery backup power supply or 24V battery backup power supply, depending on the required battery system and application.

Features

• 40W DIN rail AC/DC power supply with integrated battery charger and UPS function for applications requiring continuous DC power during AC mains interruption
• Universal 90–264VAC input with 127–370VDC input capability for flexible AC or DC power system integration
• Available in DRC-40A and DRC-40B models for 12V and 24V battery backup systems
• DRC-40A provides 13.8VDC main output with 1.9A rated current and 1A battery charger output
• DRC-40B provides 27.6VDC main output with 0.95A rated current and 0.5A battery charger output
• Adjustable main output voltage: 12–15VDC for DRC-40A and 24–30VDC for DRC-40B
• Automatic battery backup operation allows the connected battery to supply the load when AC mains power fails
• AC OK alarm signal for monitoring AC input status through TTL open collector output
• Battery Low alarm signal for monitoring low battery conditions through TTL open collector output
• Relay contact output for AC OK and Battery Low signaling available as an optional configuration
• Battery low cut-off at 10 ±0.5V for DRC-40A and 20 ±1V for DRC-40B
• Battery low alarm threshold below 11V for DRC-40A and below 22V for DRC-40B
• Built-in protection against short circuit, overload and overvoltage
• Battery reverse polarity protection by fuse for improved battery connection protection
• Overload protection operates in hiccup mode and automatically recovers after the fault condition is removed
• Fanless design with free-air convection cooling for low-maintenance operation
• Wide operating temperature range from -30°C to +70°C, subject to the datasheet derating curve
• Compact 40 × 90 × 100 mm enclosure for space-efficient control cabinet installation
• Compatible with TS35/7.5 and TS35/15 DIN rail installation
• Efficiency up to 87%, depending on model
• LED indicator for power-on status
• Passes LPS requirements and 100% full-load burn-in testing
• Safety approvals include UL62368-1, BS EN/EN62368-1, EAC TP TC 004 and AS/NZS 60950.1
• Suitable for security systems, access control systems, alarm systems, emergency lighting, DC UPS systems and central monitoring systems
• 3-year manufacturer warranty

Need help choosing between 12V and 24V battery systems? Compare DRC-40A and DRC-40B below.

Model Selection Guide for DRC-40 Series

The MEAN WELL DRC-40 Series includes two compact 40W DIN rail power supply models with integrated battery charger and UPS backup function. Engineers, OEM buyers and system integrators can select between DRC-40A and DRC-40B primarily according to the required battery system voltage, load current, battery charging current and backup power architecture.
Both models share the same universal 90–264VAC input, 127–370VDC input capability, DIN rail mounting, free-air convection cooling, AC OK and Battery Low alarm signals, battery low cut-off, battery reverse polarity protection and core output protection functions. The main difference is the DC output and battery system voltage.

DRC-40A for 12V Battery Backup Systems

The MEAN WELL DRC-40A is designed for 12V battery architectures and provides a 13.8VDC main output with 1.9A rated current. Its dedicated battery charger output provides up to 1A, making it suitable for compact security, access control, alarm and monitoring systems requiring 12V battery backup.
The main output voltage is adjustable from 12–15VDC. Battery Low signaling is activated when battery voltage falls below 11V, while battery cut-off is specified at 10 ±0.5V to help protect the connected battery during extended backup operation.
This model is a suitable choice when the system uses a 12V battery and the connected load remains within the available DRC-40A output capability.

DRC-40B for 24V Battery Backup Systems

The MEAN WELL DRC-40B is designed for 24V battery architectures and provides a 27.6VDC main output with 0.95A rated current. Its battery charger output provides up to 0.5A, supporting 24V security, monitoring, alarm and DC backup systems.
The main output voltage can be adjusted from 24–30VDC. Battery Low signaling is activated when battery voltage falls below 22V, while battery cut-off is specified at 20 ±1V.
DRC-40B is generally selected when the equipment or battery architecture is based on 24VDC and the required load current is within the model’s rated output capability.

How to Choose Between DRC-40A and DRC-40B

For most applications, model selection starts with the battery system voltage. Choose DRC-40A for 12V battery systems and DRC-40B for 24V battery systems. Then verify the connected load current, battery charging requirement, adjustable output voltage range and required backup operating time.
The DRC-40 Series is particularly suitable for applications where a single DIN rail unit must provide both regulated DC power and battery charging, with automatic battery backup when AC mains power is interrupted.

Alarm Monitoring and Backup System Integration

Both DRC-40 models provide AC OK and Battery Low signals through TTL open collector outputs on standard versions, allowing alarm panels, controllers or monitoring equipment to detect AC failure and low battery conditions. Relay contact output is available as an optional configuration.
These monitoring functions make the DRC-40 Series suitable for security systems, access control systems, alarm equipment, emergency lighting, central monitoring systems and other installations where power status and battery condition need to be supervised.
Need help choosing the correct DRC-40 model? Select DRC-40A for 12V battery systems or DRC-40B for 24V battery systems, then confirm the required load current, battery charging current, output adjustment range and backup power requirements for your application.

Related MEAN WELL DRC Series Power Supplies

For battery backup system design and DIN rail power selection, the following MEAN WELL DRC Series power supplies are closely related to the DRC-40 Series and can be compared according to required power level, battery system voltage, charging requirement, load current and installation needs:

• 
  DRC-60 Series – DIN rail AC/DC power supply with integrated battery charger and UPS function for applications requiring higher output capacity than the DRC-40 Series.
• 
  DRC-100 Series – Higher-power DRC Series solution for security, access control, monitoring and battery backup systems requiring increased load capability.
• 
  DRC-180 Series – Higher-capacity DRC Series power supply for larger security, monitoring and battery backup applications requiring increased DC output capability.

Need help selecting the right MEAN WELL DRC Series power supply?
Compare DRC-40, DRC-60, DRC-100 and DRC-180 based on required output power, battery system voltage, load current, battery charging requirement, alarm and monitoring needs, installation space and backup system design.

Battery Backup, AC OK and Battery Low Alarm Functions

The MEAN WELL DRC-40 Series integrates DC power supply, battery charging and backup control in a compact DIN rail design. It is intended for security, access control, alarm, emergency lighting and monitoring systems that require continued DC power when AC mains power is interrupted.
When AC mains is available, the DRC-40 supplies power to the connected load while charging the external battery. If AC input fails, the battery automatically supplies the load through the backup control circuit, allowing critical equipment to continue operating without a separate external DC UPS module.
Both DRC-40A and DRC-40B also provide AC OK and Battery Low alarm outputs for integration with controllers, alarm panels and monitoring systems. Standard models use TTL open collector outputs, while relay contact outputs are available as an optional configuration.

Battery Backup Operation

The DRC-40 Series is designed for direct integration with an external battery. During normal AC operation, the power supply provides energy to the load and charges the battery at the same time.
When AC mains power is interrupted, the battery begins supplying power to the connected load automatically. This allows the DRC-40 Series to function as a compact DIN rail power supply with battery backup for systems that must remain operational during temporary AC power failure.
The DRC-40A is intended for 12V battery architectures, while the DRC-40B is intended for 24V battery architectures.

AC OK Alarm Signal

The AC OK signal allows an external monitoring circuit to detect whether the power supply is operating from AC mains.
According to the DRC-40 alarm logic, the AC OK output is Low when the power supply is ON and changes to High or open when the power supply turns OFF or AC mains is lost.
This signal can be connected to an alarm panel, PLC input, controller or monitoring circuit to provide AC power status feedback.

Battery Low Alarm Signal

The Battery Low signal provides early warning when the connected battery voltage falls below the specified threshold.
For DRC-40A, the Battery Low signal is activated when battery voltage falls below 11V. For DRC-40B, the threshold is below 22V.
The alarm output changes state according to the battery condition, allowing security systems, monitoring controllers or alarm equipment to detect low battery voltage before battery cut-off occurs.

Battery Low Cut-Off Protection

To help prevent excessive battery discharge during extended backup operation, the DRC-40 Series includes battery low cut-off protection.
The specified battery cut-off voltage is 10 ±0.5V for DRC-40A and 20 ±1V for DRC-40B.
This function works together with the Battery Low alarm signal to provide both early warning and low-voltage battery protection during backup operation.

Open Collector Alarm Output

Standard DRC-40 models provide AC OK and Battery Low signals through TTL open collector outputs.
An external voltage source is required for the alarm circuit. The datasheet specifies a maximum applied voltage of 50V and a maximum sink current of 30mA.
Relay contact output is available as an optional configuration for applications that require isolated relay-based signaling rather than open collector monitoring.

Terminal Assignment and System Connection

The DRC-40 Series provides dedicated terminals for AC input, DC output, battery connection and alarm signaling.
The output-side terminal block includes connections for:

• +V / -V for the main DC load output
• Bat. + / Bat. – for the external backup battery
• AC OK for AC power status monitoring
• Bat. Low for low battery status monitoring

For correct installation, battery wiring and alarm circuit design, engineers should follow the terminal assignment and suggested application diagram provided in the DRC-40 datasheet.

DIN Rail Installation

The DRC-40 Series is designed for installation on TS35/7.5 or TS35/15 DIN rail. Its compact 40 × 90 × 100 mm enclosure allows integration into security panels, control cabinets, access control enclosures and other space-constrained electrical installations.
The datasheet recommends installation clearances of 40mm above, 20mm below and 5mm on the left and right sides when operating continuously at full power. When an adjacent device is a heat source, a 15mm side clearance is recommended.
Need wiring and installation details for the DRC-40 Series? Review the connection diagram, terminal assignment and mechanical drawing below, or refer to the official DRC-40 datasheet for complete battery wiring, alarm output and DIN rail installation information.

Mechanical Dimensions and Installation

The MEAN WELL DRC-40 Series features a compact DIN rail enclosure measuring 40 × 90 × 100 mm (W × H × D), allowing installation inside security panels, access control cabinets, alarm enclosures and other space-constrained DC backup systems.
The series is designed for TS35/7.5 or TS35/15 DIN rail mounting and uses free-air convection cooling without a built-in fan. Its compact mechanical format integrates AC input, DC output, battery connection and alarm signaling within a single DIN rail power supply platform.

Dimensions

The overall dimensions of the DRC-40 Series are 40 mm wide, 90 mm high and 100 mm deep, with a specified dimensional tolerance of ±1 mm.
Both DRC-40A and DRC-40B use the same mechanical enclosure, making it easier to standardize panel layout when selecting between 12V and 24V battery backup architectures.
The compact 40 mm width helps reduce cabinet space while maintaining integrated power supply, battery charging and backup control functions.

Terminal Assignment

The DRC-40 Series uses separate terminal blocks for input power and output-side system connections.
TB1 input terminals:

• Pin 1: AC/L or DC+
• Pin 2: AC/N or DC-
• Pin 3: FG

TB2 output and signal terminals:

• Pin 1: -V
• Pin 2: +V
• Pin 3: Bat. +
• Pin 4: Bat. –
• Pins 5–6: AC OK
• Pins 7–8: Bat. Low

These terminals provide the required connections for AC or DC input, main DC load output, external backup battery and alarm status monitoring.

DIN Rail Installation

The DRC-40 Series is designed to fit TS35/7.5 or TS35/15 DIN rail. The DIN rail itself is not included with the power supply.
For installation, the unit should be mounted vertically according to the mechanical and installation instructions shown in the official datasheet. Correct mounting orientation helps maintain proper free-air convection and thermal performance.
The compact DIN rail format makes the DRC-40 Series suitable for control cabinets, security system enclosures, access control panels and centralized monitoring equipment where installation space is limited.

Installation Clearance

For continuous full-power operation, the datasheet recommends the following minimum installation clearances:

• 40 mm above the power supply
• 20 mm below the power supply
• 5 mm on the left and right sides

If an adjacent device is a heat source, a side clearance of 15 mm is recommended.
These clearances help maintain sufficient natural airflow around the fanless enclosure and reduce thermal stress during continuous operation.

Cooling and Operating Environment

The DRC-40 Series uses free-air convection cooling and does not require a fan. The specified operating temperature range is -30°C to +70°C, subject to the derating curve in the datasheet.
For operating altitudes above 2000 m, the datasheet specifies additional ambient temperature derating for fanless models. System designers should consider load level, ambient temperature, surrounding heat sources and cabinet ventilation when integrating the DRC-40 into enclosed equipment.

Mechanical Drawing and Installation Reference

The mechanical drawing shows the enclosure dimensions, terminal locations, front-panel adjustment and indication area, rear DIN rail mounting structure and recommended TS35 installation method.
For final panel design and wiring, engineers should refer to the official DRC-40 mechanical drawing and installation instructions to confirm terminal spacing, mounting clearance and system connection details.
Need application and compliance information for the DRC-40 Series? Continue below to review recommended applications, safety approvals, EMC compliance and battery backup system guidance.

Applications

The MEAN WELL DRC-40 Series is designed for security, access control and backup power applications that require a compact 40W DIN rail AC/DC power supply with integrated battery charger and UPS function.
With universal 90–264VAC input, 13.8V or 27.6V output options, automatic battery backup operation, AC OK and Battery Low alarm signals, battery low cut-off and DIN rail installation, the DRC-40 Series provides a practical DC backup solution for systems that must remain operational during temporary AC mains interruption.

• Security systems requiring regulated DC power, battery charging and automatic backup operation
• Access control systems including controllers, door access panels and related security equipment requiring 12V or 24V battery backup
• Alarm systems requiring continuous DC power and AC OK / Battery Low status monitoring
• Emergency lighting systems requiring battery-supported DC power during AC mains failure
• DC UPS systems using an external battery for automatic backup power when AC input is interrupted
• Central monitoring systems requiring power status and low-battery signaling for system supervision

Need certification and compliance details for your project? Continue below to review safety approvals, EMC compliance, protection functions and operating environment specifications for the DRC-40 Series.

Certifications and Safety

The MEAN WELL DRC-40 Series is designed for security, access control, alarm, emergency lighting and DC backup applications requiring reliable AC/DC conversion, battery charging and internationally recognized safety and EMC compliance.
According to the official DRC-40 datasheet, the series carries the following safety approvals:

• UL62368-1 for information and communication technology equipment safety
• TÜV BS EN/EN62368-1 for European safety compliance
• EAC TP TC 004 for Eurasian safety requirements
• AS/NZS 60950.1 for applicable Australia and New Zealand safety requirements

The DRC-40 Series also passes LPS (Limited Power Source) requirements and is subjected to a 100% full-load burn-in test as part of the manufacturer’s production and reliability control process.

EMC Emission Compliance

For electromagnetic emission requirements, the DRC-40 Series complies with:

• BS EN/EN55032 (CISPR32) Class B
• BS EN/EN61000-3-2
• BS EN/EN61000-3-3
• EAC TP TC 020

Class B emission compliance supports use in light-industrial and similar equipment environments where conducted and radiated electromagnetic emissions must remain within applicable limits.

EMC Immunity Compliance

The series also complies with EMC immunity requirements including:

• BS EN/EN61000-4-2 electrostatic discharge immunity
• BS EN/EN61000-4-3 radiated RF immunity
• BS EN/EN61000-4-4 electrical fast transient immunity
• BS EN/EN61000-4-5 surge immunity
• BS EN/EN61000-4-6 conducted RF immunity
• BS EN/EN61000-4-8 power-frequency magnetic field immunity
• BS EN/EN61000-4-11 voltage dips and interruption immunity
• BS EN/EN55035
• BS EN/EN61204-3
• EAC TP TC 020

Isolation and Electrical Safety

The DRC-40 Series specifies the following withstand voltage levels:

• Input to output: 3KVAC
• Input to FG: 2KVAC
• Output to FG: 0.5KVAC

Isolation resistance is specified at 100MΩ minimum between input-output, input-FG and output-FG under the datasheet test conditions.

Protection Functions

Built-in protection functions include short circuit, overload and overvoltage protection, together with battery low cut-off and battery reverse polarity protection by fuse.
For overload conditions, the DRC-40 Series uses hiccup-mode protection and automatically recovers after the fault condition is removed. Overvoltage protection shuts down the output and requires AC power to be cycled to recover.

Final Equipment Compliance

The DRC-40 Series is supplied as a component power supply intended for installation inside final equipment. The official datasheet states that the completed equipment must be re-confirmed for EMC compliance after system integration.
System designers should therefore verify grounding, enclosure design, wiring layout, installation clearance, thermal conditions and electromagnetic compatibility in the final security, access control, alarm or backup power system.
Need more product details before sending an inquiry? Continue below to review model comparison, battery backup operation, alarm signaling, mechanical dimensions, installation guidance and application information for the DRC-40 Series.