MEAN WELL LAD-600 Series 600W Security & Fire Alarm Power Supply with Battery Charger & UPS

Overview of MEAN WELL LAD-600 Series

The MEAN WELL LAD-600 Series combines regulated DC output, dedicated battery charging, UPS backup control and system monitoring in a low-profile 600W AC/DC security and fire alarm power supply. It is designed for fire emergency, security, public safety backup and other systems that require normal DC operation together with battery-supported operation when AC mains power becomes abnormal.

During normal AC operation, the LAD-600 supplies power to the connected load while charging the external battery. If the AC input becomes abnormal, the built-in UPS function switches the power source to battery backup so connected equipment can continue operating during mains interruption. The series also supports forced UPS operation, while the UART versions additionally provide remote UPS control for integration with fire alarm and evacuation systems.

The series is available in three output versions. LAD-600B provides a 27.6V main output rated at 18.74A, LAD-600C provides 41.5V at 11.45A, and LAD-600D provides 55.2V at 7.87A. Each model also provides a dedicated 3A battery charging output. UART communication versions are available as LAD-600BU, LAD-600CU and LAD-600DU, and the series is suitable for both lead-acid and lithium-ion batteries.

For system monitoring, the standard LAD-600 versions provide TTL status signals for AC OK, battery disconnect or reverse polarity, battery low, battery full and discharge status. The UART versions support communication-based monitoring and control, including power supply status, battery voltage, mains voltage, output voltage and output current. They also provide buzzer alarm functionality, battery inspection connections and additional battery-related control features.

Built-in protection functions include short circuit, overload, overvoltage, overtemperature, battery low-voltage protection and battery reverse-polarity protection. With a low-profile 225 × 124 × 41 mm design, built-in AC and battery circuit ON/OFF switches and efficiency up to 91%, the LAD-600 Series is suitable for fire emergency and evacuation systems, public safety battery backup, security systems, DC UPS systems, central monitoring systems and industrial automation.

Features

• 600W AC/DC security and fire alarm power supply with dedicated main output and 3A battery charging output
• 90–132VAC or 180–264VAC input selectable by switch, with 240–370VDC input capability and up to 91% typical efficiency
• LAD-600B provides 27.6V main output rated at 18.74A
• LAD-600C provides 41.5V main output rated at 11.45A
• LAD-600D provides 55.2V main output rated at 7.87A
• UART communication versions available as LAD-600BU, LAD-600CU and LAD-600DU
• Built-in battery charger and automatic UPS backup operation during abnormal AC input
• Standard versions provide TTL status signals for AC OK, battery disconnect or reverse polarity, battery low, battery full and discharge monitoring
• UART versions support communication-based monitoring and control, including power supply status, battery voltage, mains voltage, output voltage, output current and selected operating parameters
• Forced start UPS mode and remote UPS control support emergency operation, maintenance and system testing
• Battery inspection and selectable charging modes support lead-acid and lithium-ion battery systems on UART versions
• Short circuit, overload, overvoltage, overtemperature, battery low-voltage and reverse-polarity protection
• Low-profile 225 × 124 × 41 mm design with built-in AC and battery circuit ON/OFF switches

Need help selecting the correct output voltage and communication version for your system? Compare LAD-600B, LAD-600C, LAD-600D, LAD-600BU, LAD-600CU and LAD-600DU below.

Model Selection Guide for LAD-600 Series

The MEAN WELL LAD-600 Series includes three 600W-class output versions with built-in battery charger and UPS backup function: LAD-600B, LAD-600C and LAD-600D. Each output version is also available with UART communication as LAD-600BU, LAD-600CU and LAD-600DU.

Model selection is primarily determined by the required DC output voltage, load current, battery system and monitoring interface. Standard models use TTL status signals, while U versions provide UART communication with additional monitoring, battery inspection and UPS control functions.

All models share the same 90–132VAC or 180–264VAC input selectable by switch, with 240–370VDC input capability, 3A battery charging output, UPS backup function, forced UPS operation, battery reverse-polarity protection and 225 × 124 × 41 mm low-profile design. The main electrical differences are output voltage, rated current, rated power, voltage adjustment range, efficiency and battery low-voltage cut-off threshold.

LAD-600B / LAD-600BU – 27.6V Output

The MEAN WELL LAD-600B and LAD-600BU provide a 27.6V main output rated at 18.74A together with a 27.6V battery charging output rated at 3A. Rated power is 600.02W.

The main output voltage can be adjusted from 21.6V to 29V. Battery low-voltage cut-off is specified at 21.5V ±0.5V, and typical efficiency is 90%.

Choose LAD-600B when TTL status monitoring is sufficient. Choose LAD-600BU when the system requires UART communication, remote monitoring, battery inspection or additional UPS control functions.

LAD-600C / LAD-600CU – 41.5V Output

The MEAN WELL LAD-600C and LAD-600CU provide a 41.5V main output rated at 11.45A together with a 41.5V battery charging output rated at 3A. Rated power is 599.67W.

The main output voltage can be adjusted from 32.4V to 43.5V. Battery low-voltage cut-off is specified at 32V ±0.5V, and typical efficiency is 91%.

Choose LAD-600C for systems requiring a 41.5V output with TTL status monitoring. LAD-600CU adds UART communication, battery inspection and additional monitoring and control capabilities.

LAD-600D / LAD-600DU – 55.2V Output

The MEAN WELL LAD-600D and LAD-600DU provide a 55.2V main output rated at 7.87A together with a 55.2V battery charging output rated at 3A. Rated power is 600.02W.

The main output voltage can be adjusted from 43.5V to 58V. Battery low-voltage cut-off is specified at 43V ±0.5V, and typical efficiency is 91%.

LAD-600D and LAD-600DU are the highest-voltage models in the series and are suitable where the connected load and backup battery architecture require a 55.2V output.

How to Choose Between LAD-600B, LAD-600C and LAD-600D

Start with the required DC output voltage. Choose LAD-600B or LAD-600BU for 27.6V, LAD-600C or LAD-600CU for 41.5V, and LAD-600D or LAD-600DU for 55.2V output.

Then confirm the required load current. The 27.6V models provide up to 18.74A, the 41.5V models provide up to 11.45A, and the 55.2V models provide up to 7.87A. All versions provide a dedicated 3A battery charging output.

When AC input is normal, the LAD-600 supplies the connected load while charging the external battery. When the AC input becomes abnormal, the built-in UPS function switches the system to battery backup operation.

Choose TTL or UART Communication

The standard LAD-600B, LAD-600C and LAD-600D versions provide TTL status signals for AC OK, battery disconnect or reverse polarity, battery low, battery full and discharge status. The TTL interface requires an external voltage source and supports up to 50VDC applied voltage with a maximum sink current of 30mA.

The LAD-600BU, LAD-600CU and LAD-600DU versions use UART communication for system monitoring and control. Through UART, the power supply can communicate fault signals, operating status, individual battery voltage information, mains voltage, output voltage and output current to an external controller, while also accepting control instructions from the controller.

Choose the standard version when simple hardware status signals are sufficient. Choose the UART version when the application requires communication-based monitoring, centralized control, battery inspection or integration with a fire alarm or evacuation control system.

Forced and Remote UPS Control

The standard LAD-600 models provide forced UPS mode through CN2 pins 7 and 8. Shorting these pins activates forced UPS operation, while leaving them open keeps the unit in normal operating mode.

The UART versions provide additional UPS control functions. CN2 pins 1 and 2 are used for forced start, while pins 3 and 4 provide remote UPS control. The U versions also use pins 5 and 6 for lead-acid or lithium-ion battery selection and pins 7 and 8 for fire alarm or evacuation buzzer mode selection.

Battery inspection connections are also provided on the UART versions, allowing individual battery voltage information to be monitored according to the battery configuration of LAD-600BU, LAD-600CU or LAD-600DU.

Need help choosing the correct LAD-600 model? Start with the required output voltage, then confirm load current, battery charging requirements and whether your system needs simple TTL status monitoring or UART-based communication, battery inspection and control.

Related MEAN WELL LAD, PSC and Security Power Supplies

For security systems, fire alarm systems, emergency power, central monitoring and battery backup applications, the following MEAN WELL power supplies can be compared with the LAD-600 Series according to required output power, output voltage, battery charging capability, UPS function, monitoring requirements, communication functions and installation format:

• LAD-120 Series – Lower-power LAD Series security and fire alarm power supply with integrated battery charger, UPS backup function and TTL status monitoring for applications requiring substantially less output capacity than LAD-600.
• LAD-240 Series – 240W LAD Series security and fire alarm power supply with battery charger, UPS backup function and status monitoring for systems requiring lower load power and charging capacity than LAD-600.
• LAD-360 Series – 360W LAD Series security and fire alarm power supply with battery charger, UPS backup, TTL status monitoring and optional UART communication for applications that require less output capacity than LAD-600 while retaining similar backup and monitoring functions.
• PSC-35 Series – Lower-power AC/DC power supply with integrated battery charger and UPS backup function for security and battery-backed DC applications with lighter load requirements.
• PSC-60 Series – Compact 60W power supply with battery charger and UPS function for applications requiring significantly lower output power than LAD-600.
• PSC-100 Series – 100W battery charger power supply with UPS backup function for security, alarm and DC backup applications requiring lower output power and simpler system integration.
• PSC-160 Series – 160W AC/DC power supply with integrated battery charger and UPS backup function for systems requiring moderate output power below the LAD-600 Series.
• DRC-100 Series – DIN rail security power supply with battery charging and automatic backup operation for applications that require DIN rail mounting rather than a low-profile chassis.
• DRC-180 Series – Higher-power DIN rail AC/DC power supply with battery charger and UPS function for security and backup systems that require TS35 rail installation.
• DRS-240 Series – Intelligent DIN rail security power supply integrating AC/DC power, battery charger, DC UPS, status monitoring and communication functions for advanced backup power and supervisory applications.
• DRS-480 Series – 480W intelligent DIN rail security power supply with battery charging, DC UPS, monitoring and communication functions for applications that prioritize DIN rail installation and advanced system control.

Need help selecting the right MEAN WELL security power supply?
Compare LAD, PSC, DRC and DRS Series based on required output voltage, load power, battery charging current, UPS backup operation, TTL or UART monitoring, communication functions and installation format.

Battery Backup and Status Monitoring Functions

The MEAN WELL LAD-600 Series combines battery charging, UPS backup and system status monitoring for security, fire alarm, evacuation and DC backup systems. Standard versions use TTL status outputs, while U versions add UART communication, battery inspection and additional UPS control functions.

Battery Backup Operation

During normal AC operation, the LAD-600 powers the connected load while charging the external battery. If the AC input becomes abnormal, the UPS function transfers the load to battery-supported operation so the connected equipment can continue running.

The series includes LAD-600B at 27.6V, LAD-600C at 41.5V and LAD-600D at 55.2V. UART versions are available as LAD-600BU, LAD-600CU and LAD-600DU. All versions provide a dedicated 3A battery charging output.

TTL Status Monitoring

The standard LAD-600B, LAD-600C and LAD-600D versions provide multiple TTL status signals through CN2:

• AC OK: Indicates normal or abnormal AC input status
• Battery Disconnect / Reverse Polarity: Indicates a disconnected or incorrectly connected battery during initial power-up
• Battery Low: Indicates a battery undervoltage condition
• Battery Full: Indicates full-charge status
• Discharge: Indicates battery-backed operation

The TTL outputs require an external voltage source and support up to 50VDC with a maximum sink current of 30mA.

UART Monitoring and Control

The LAD-600BU, LAD-600CU and LAD-600DU use UART communication for more detailed system integration.

An external controller can receive fault information, operating status, individual battery voltage, mains voltage, output voltage and output current. UART communication also supports selected control and configuration functions, including backup power switching and battery undervoltage-related settings.

This makes the U versions better suited to centralized monitoring, fire alarm control and evacuation systems that require communication between the power supply and an external controller.

Battery Low-Voltage Cut-Off Protection

Battery low-voltage protection helps prevent excessive discharge during extended backup operation:

• LAD-600B / LAD-600BU: 21.5V ±0.5V
• LAD-600C / LAD-600CU: 32V ±0.5V
• LAD-600D / LAD-600DU: 43V ±0.5V

Battery reverse-polarity protection prevents damage if the battery is connected incorrectly and automatically recovers after the wiring fault is corrected.

Forced UPS Mode

The standard LAD-600B, LAD-600C and LAD-600D versions provide forced UPS mode through CN2 pins 7 and 8.

Shorting pins 7 and 8 activates forced UPS operation. Leaving them open keeps the unit in normal operating mode. This function allows battery-backed operation to be tested or activated for maintenance and emergency use without waiting for an actual mains failure.

Forced Start and Remote UPS Control for UART Versions

The UART versions provide two additional UPS control methods through CN2.

Pins 1 and 2 are used for forced start. In this mode, the battery undervoltage alarm remains active, but battery undervoltage protection is disabled. The battery can therefore continue discharging until the system shuts down.

Pins 3 and 4 provide remote UPS control. This allows an external fire alarm or control system to command UPS operation while retaining battery undervoltage alarm and protection.

Battery Type Selection and Inspection

The U versions also provide battery configuration and inspection functions.

Pins 5 and 6 select the charging mode for lead-acid or lithium-ion batteries. Dedicated battery inspection connections allow individual battery voltages to be monitored according to the model:

• LAD-600BU: Battery inspection for a 24V battery system
• LAD-600CU: Battery inspection for a 36V battery system
• LAD-600DU: Battery inspection for a 48V battery system

Need wiring and connector details? Continue below for the LAD-600 mechanical drawing, TB1 terminal assignment, CN2 TTL and UART pin assignments, battery inspection connections and installation information.

Mechanical Dimensions and Installation

The MEAN WELL LAD-600 Series uses a compact low-profile chassis for integration into security, fire alarm, evacuation, battery backup and DC UPS equipment. Its 41 mm enclosure height helps simplify installation in control cabinets and equipment housings where space is limited.

Dimensions

The LAD-600 Series measures 225 × 124 × 41 mm (L × W × H) and uses Case No. 292B.

The enclosure includes the TB1 power terminal block, CN2 signal connector, AC ON/OFF switch, battery connected/disconnected switch, mounting points and defined airflow direction. Standard TTL and UART versions use the same main mechanical platform.

TB1 Terminal Assignment

Power input, DC output and battery connections are made through the TB1 terminal block:

• Pin 1: AC/L
• Pin 2: AC/N
• Pin 3: FG
• Pin 4: DC OUTPUT -V
• Pin 5: DC OUTPUT +V
• Pin 6: BAT –
• Pin 7: BAT +

CN2 Assignment for Standard TTL Versions

For LAD-600B, LAD-600C and LAD-600D, CN2 provides status monitoring and forced UPS control:

• Pin 1: AC OK
• Pin 2: Battery disconnect / reverse polarity
• Pin 3: Battery Low
• Pin 4: GND
• Pin 5: Battery Full
• Pin 6: Discharge
• Pins 7 and 8: Open for normal operation; short for forced UPS mode

The recommended mating housing is TKP DH2 or equivalent, with TKP DHT-1S(LF) or equivalent terminals.

CN2 Assignment for UART Versions

For LAD-600BU, LAD-600CU and LAD-600DU, CN2 uses a 16-pin interface for UART communication, UPS control, battery selection and battery inspection:

• Pins 1 and 2: Forced start
• Pins 3 and 4: Remote UPS control
• Pins 5 and 6: Lithium-ion / lead-acid battery selection
• Pins 7 and 8: Fire alarm / evacuation system option
• Pin 9: BAT1
• Pin 10: BAT2 where applicable
• Pin 11: NC
• Pin 12: BAT3 where applicable
• Pin 13: UART_RX
• Pin 14: UART_TX
• Pin 15: GND
• Pin 16: 3.3V reference for testing

Operating Environment and Derating

The LAD-600 Series operates from -20°C to +60°C. Full output is available through the lower and mid-range ambient temperatures, with output derating required as temperature approaches the upper operating limit.

The enclosure includes a defined airflow direction. Adequate ventilation should be provided when the unit is installed inside a larger enclosure, particularly in higher ambient temperatures or continuous high-load applications.

Mounting and Installation

The mechanical drawing identifies the overall dimensions, mounting points, TB1 and CN2 positions, AC ON/OFF switch, battery switch and airflow direction.

Optional mounting brackets are available under MEAN WELL order number PGG2MHS012. The installation drawing shows a 225 mm overall unit length and approximately 150 mm bracket mounting spacing.

Final enclosure design should allow sufficient clearance for wiring, airflow, terminal access and maintenance of the AC and battery switches.

Need complete installation details? Review the LAD-600 mechanical drawing and wiring information for TB1 connections, CN2 TTL or UART assignments, battery inspection, UPS control and mounting requirements.

Applications

The MEAN WELL LAD-600 Series is designed for security, fire alarm, evacuation and backup power applications requiring regulated DC output, battery charging, UPS operation and external system monitoring.

With LAD-600B, LAD-600C and LAD-600D covering 27.6V, 41.5V and 55.2V output versions, plus UART communication models LAD-600BU, LAD-600CU and LAD-600DU, the series provides a flexible 600W-class platform for systems that require continuous DC operation, battery-supported backup, status detection and communication-based monitoring or control.

• Fire emergency and evacuation systems requiring reliable DC power, battery charging, backup operation and UPS control during abnormal AC input
• Security systems requiring regulated DC power together with battery backup and system status monitoring
• Public safety battery backup systems requiring continued operation from an external battery during AC mains interruption
• Uninterruptible DC-UPS systems requiring automatic transfer to battery-supported operation when AC input becomes abnormal
• Central monitoring systems using TTL status signals or UART communication for power supply, battery and operating status monitoring
• Fire alarm and evacuation control systems requiring forced start, remote UPS control and communication-based integration with an external controller
• Industrial automation systems requiring regulated DC output, battery charging, backup power integration and centralized monitoring

Need safety and compliance details for your project? Continue below to review protection functions, safety approvals, EMC compliance and operating environment specifications for the LAD-600 Series.

Certifications and Safety

The MEAN WELL LAD-600 Series is a 600W AC/DC security and fire alarm power supply designed for systems that combine regulated DC output, battery charging, UPS backup and status monitoring.

The series carries safety approvals including UL62368-1, BS EN/EN62368-1, AS/NZS62368.1 and EAC TP TC 004. Product design also references GB 17945-2010, with GB 4717 additionally referenced for the UART communication versions.

Safety and EMC Compliance

Key safety and EMC standards include:

• UL62368-1
• BS EN/EN62368-1
• AS/NZS62368.1
• EAC TP TC 004
• GB 17945-2010 design reference
• GB 4717 additional design reference for UART versions
• BS EN/EN55032 (CISPR32) Class A conducted and radiated emissions
• BS EN/EN61000-4-2, -4-3, -4-4, -4-5, -4-6 and -4-8 immunity tests
• EAC TP TC 020 EMC requirements

Isolation and Electrical Safety

Withstand voltage ratings are:

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

Isolation resistance is 100MΩ between input-output, input-FG and output-FG when tested at 500VDC, 25°C and 70% RH.

Protection Functions

The LAD-600 Series includes protection against short circuit, overload, overvoltage, overtemperature, battery low voltage and battery reverse polarity.

With a battery connected, CH1 overload can transfer the unit into UPS operation at approximately 105% to 120% of CH1 load. If the combined CH1 and CH2 output reaches approximately 125% to 135%, the output shuts down.

Without a battery connected, CH1 overload causes output shutdown. CH2 uses constant-current limiting, and a charger-side fault does not prevent CH1 from continuing to operate. CH2 automatically recovers when the fault is removed.

Overvoltage and overtemperature protection shut down the output. After these shutdown protections are triggered, disconnect the input power and allow the unit to cool for approximately 3 minutes before restarting.

Battery reverse-polarity protection prevents damage and automatically recovers once the incorrect connection is removed.

Battery Protection and UPS Safety

Battery low-voltage cut-off levels are:

• LAD-600B / LAD-600BU: 21.5V ±0.5V
• LAD-600C / LAD-600CU: 32V ±0.5V
• LAD-600D / LAD-600DU: 43V ±0.5V

Forced start on the UART versions intentionally changes the normal battery protection behavior. The battery undervoltage alarm remains available, but undervoltage shutdown protection is disabled, allowing the battery to continue discharging until the system shuts down.

Remote UPS control retains both the battery undervoltage alarm and battery undervoltage protection.

Operating Environment and Final Equipment Integration

The LAD-600 Series operates from -20°C to +60°C, with output derating required at higher ambient temperatures.

The power supply is a component intended for installation inside final equipment. EMC performance therefore depends not only on the power supply itself but also on enclosure construction, wiring layout, grounding, cable routing and system configuration.

MEAN WELL’s EMC test configuration uses the power supply mounted on a 360 × 360 × 1 mm metal plate. Radiated EMC testing also uses an additional 20 × 30 × 13 mm NiZn magnetic clasp or magnetic ring on the battery output line.

Final equipment should be evaluated for applicable safety and EMC requirements after the LAD-600 has been integrated into the complete system.

Need more product details before sending an inquiry? Review the model comparison, battery backup functions, TTL and UART monitoring, UPS control, mechanical dimensions and installation information above.