MEAN WELL AD-155B 155W Single Output Battery Charger - UPS Function

Our review of the MEAN WELL AD-155B finds it best suited for technicians and small-system integrators who need a compact AC to DC power supply with an integrated battery charger and UPS function. The single most compelling reason to buy is its dependable dual-output design that pairs a strong 27.6 VDC, 5 A primary output with a secondary 27.1 VDC charging line, delivering reliable backup capability without separate chargers. In practice it performs as a straightforward, no-frills power module that balances safety protections and useful power density for continuous and backup applications.

Key Features

• Dual output with UPS function: The primary 27.6 VDC 5 A output and secondary 27.1 VDC 0.5 A charging line keep a battery charged while supplying load power and enabling seamless backup switching.
• Universal AC input: Input range from 88 to 264 VAC and 47 to 63 Hz makes installation flexible across international mains without extra configuration.
• Built-in protections: Short circuit, overload, over voltage, battery low and reverse polarity protections reduce risk to connected batteries and equipment.
• Convection cooled: Free air convection cooling requires no additional fans, simplifying installation and reducing mechanical noise.
• High switching frequency: Fixed switching frequency design with PFC at 67 kHz and PWM at 134 kHz helps maintain stable regulation under varying loads.

Who It's For

The AD-155B is aimed at installers and small-business users who need a compact AC to DC supply with a built-in charger and UPS capability for telecom cabinets, security systems, or industrial control panels. It fits well where a 27.6 VDC 5 A feed and a modest 0.5 A charging circuit suffice and where simple screw terminal wiring is preferred.

Those needing larger charging currents, multiple high-current outputs, or an integrated user interface should look elsewhere; this unit prioritizes robust basic functions over advanced monitoring or higher-power battery charging. It is not a consumer UPS with sine wave output for PCs, but a specialized power module for equipment and battery maintenance.

Pros & Cons

Pros

• Reliable combination of a 27.6 VDC 5 A main output with a dedicated 27.1 VDC charging output for continuous operation and battery backup.
• Wide AC input range and PFC improve compatibility and efficiency in varied environments.
• Comprehensive protections and 100 percent full-load burn-in testing give confidence for long-term deployment.

Cons

• Charging current on the secondary output is limited to 0.5 A, so charging large battery banks will be slow.

Specifications

Product type	AC to DC power supply with battery charger
Primary output voltage (VDC)	27.6
Output current (A)	5
Maximum output power (W)	151.55
Additional output (VDC)	27.1 (0.5 A charging)
Input voltage	88 to 264 VAC, 47 to 63 Hz
Output connector	Screw terminal block

Our Verdict

The MEAN WELL AD-155B is a practical choice for professionals needing a compact, reliable 27.6 VDC supply with an integrated battery charger and UPS function; it delivers solid protections, flexible AC compatibility, and convection cooling at a reasonable value. Buy it if you need dependable backup for telecom, security, or control systems and can work within the 0.5 A charge-current limitation.

Frequently Asked Questions

Does this unit provide uninterrupted power during mains loss?
Yes, the AD-155B includes a battery charger and UPS function designed to switch to battery power for connected loads when mains fails.

What charging current is available for the battery?
The dedicated charging output provides 27.1 VDC at 0.5 A, intended for maintenance charging rather than rapid recharge of large banks.

Is active cooling required for installation?
No, the design uses free air convection cooling; ensure adequate ventilation but no fan is required.