Altronix AL400ULXB2 12/24VDC Power Supply & Battery Charger
The Altronix AL400ULXB2 is a UL-listed power supply and battery charger delivering selectable 12VDC or 24VDC output in a board-level form factor. Designed for security integrators deploying access control, alarm, and distributed security systems, the AL400ULXB2 handles both live-circuit power and simultaneous battery charging in a single compact module. The unit draws 3.5A maximum at 115VAC input (60Hz), making it suitable for installations where dedicated AC circuits may be shared or space-constrained.
Key Features
- Selectable Output Voltage: Choose 12VDC or 24VDC at the terminal — eliminates the need to stock separate supply models for mixed voltage environments. 24VDC is increasingly common in modern access readers, magnetic locks, and distributed controllers, while 12VDC remains standard for legacy alarm panels and legacy sensor networks.
- High Current Capacity: Delivers 10A @ 12VDC or 8A @ 24VDC. At 12VDC, that's 120W of total system power — enough for a small distributed installation with multiple readers, door controllers, and sensors. At 24VDC, you get 192W, supporting higher-power solenoids and multi-door failsafe locks without supplemental supplies.
- Integrated Battery Backup & Charging: Built-in battery charger means you can connect a 12V or 24V lead-acid battery directly to the unit without a separate charger module. The AL400ULXB2 manages float and boost cycles automatically, extending battery life and eliminating charger compatibility questions in the field.
- AC Fail Supervision Alarm: Detects mains power loss immediately and signals an alarm condition — critical for access control and egress compliance. The alarm output lets you trigger a panel notification, send an alert, or log the event before the system switches to battery.
- Low Battery & Battery Presence Monitoring: Built-in voltage monitoring detects when battery capacity drops below usable threshold or if a battery is missing entirely. Prevents surprise power loss during a door-strike or reader operation.
- Compact Board Form Factor: Measures 7.1" × 4.5" × 1.44" and mounts directly to DIN rail or inside a 6U cabinet, saving physical space compared to larger modular supplies. Wire terminals accept up to 12 AWG conductors, supporting both small-gauge sensor wiring and larger-gauge power runs to remote devices.
Integration & Compatibility
The AL400ULXB2 integrates into any access control or alarm system requiring dual-voltage backup power. Typical deployments include:
- Access Control Hubs: Powers readers, keypad entry points, and electronic locks while a battery backs up the controller during AC outages.
- Alarm Panels with Distributed I/O: Acts as the primary power source for wireless bridges, contact modules, or relay boards scattered across a facility.
- Multi-Door Failsafe Installations: In 24VDC mode, supplies power to multiple magnetic locks or electronic strikes without voltage sag, ensuring reliable door operation under full load.
The single output connector uses industry-standard terminal blocks, compatible with both 12V and 24V lead-acid batteries (4–7 Ah typical for small systems, up to 20 Ah for extended runtime). No proprietary battery connectors or adapters required.
Operating Conditions & Reliability
Rated for 0°C to 49°C (32°F to 120°F) operating temperature, the AL400ULXB2 suits most indoor security closets, server rooms, and climate-controlled equipment racks. If your installation is in an unheated garage or outdoor cabinet, factor in additional thermal management or enclosure insulation. The UL listing confirms code compliance for fire alarm, security, and life-safety applications — required for any system that ties to emergency egress or fire suppression interfaces.
What's in the Box
- 1x Altronix AL400ULXB2 board-level power supply/charger
- 1x Terminal block connector set
When to Choose a Different Model
If your installation requires 48VDC (fiber-optic converters, IP phones) or higher output current (above 10A @ 12VDC), explore the Altronix multi-output or higher-amperage variants in the same family. For systems needing redundant power supplies or automatic failover between primary and backup AC sources, consider a dual-supply configuration or an Altronix supervised distribution module. If you need remote monitoring of power status and battery health over IP, pair the AL400ULXB2 with a networked supervisor or SNMP gateway.
Frequently Asked Questions
Q: Can I use the AL400ULXB2 with a lithium battery instead of lead-acid?
A: The AL400ULXB2 charger is optimized for lead-acid batteries. Lithium batteries require different charging profiles (constant-current/constant-voltage, temperature compensation). Using a lithium battery without a compatible charger may damage the battery or reduce its lifespan. Consult the battery manufacturer or contact Altronix technical support before substituting battery chemistry.
Q: What happens if AC power fails while the system is running at full load?
A: The AL400ULXB2 automatically switches to battery power when AC input is lost. The AC fail alarm activates immediately, alerting your system that backup power is in use. Depending on battery capacity and total load current, the system can remain operational for minutes to hours. For critical access or life-safety applications, size the battery to guarantee minimum runtime (typically 24 hours for egress and alarm systems).
Q: Is the AL400ULXB2 suitable for outdoor cabinet installation?
A: The operating temperature range is 0°C to 49°C (32°F to 120°F). In climates where outdoor cabinets regularly exceed 49°C (e.g., direct sunlight on metal enclosures), the supply may throttle or shut down for thermal protection. Use a thermally insulated or ventilated cabinet, or relocate the supply indoors. For extreme cold (below 0°C), battery charging efficiency may drop significantly.
Q: Can I charge two separate batteries with one AL400ULXB2?
A: No. The AL400ULXB2 has a single output connector. If you need to charge two batteries independently, you would need two separate supplies or a multi-channel charger.
Q: What is the maximum battery capacity I can connect?
A: The datasheet does not specify an absolute maximum. Typical lead-acid batteries range from 4 Ah to 20 Ah for security applications. Larger batteries may extend runtime but will also extend charging time. Verify the charger's amperage rating and the battery's acceptance current to avoid overcharging. For batteries larger than 20 Ah, consult Altronix engineering.
Q: Is the AL400ULXB2 code-compliant for fire alarm or life-safety systems?
A: Yes. The unit is UL listed, which satisfies code requirements for fire alarm panels, emergency egress systems, and life-safety applications. Always verify local authority having jurisdiction (AHJ) requirements and any specific panel manufacturer certifications.
Ted PerryPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
I see the AL400ULXB2 deployed frequently in mid-sized access control rollouts and multi-floor alarm system expansions where voltage standardization isn't yet locked down. The dual-voltage selector is the real time-saver here — you avoid last-minute supply swaps and the inventory overhead of maintaining separate 12V and 24V stocks. I've pulled it into three separate jobs this quarter alone because integrators needed battery backup but didn't want to engineer a separate charger subsystem.
Technical Highlights:
- 10A @ 12VDC / 8A @ 24VDC Output: Sufficient for single-door failsafe setups (magnetic lock + reader + controller draws roughly 2–4A under normal operation). The 24VDC mode is particularly useful because modern solenoids and electronic strikes are trending toward 24V, and the 8A limit means you can reliably drive two or three locks from one supply without voltage droop.
- Integrated Battery Charger with AC Fail Supervision: Eliminates the need to wire a separate battery charger module and reduces single points of failure. The AC fail alarm output gives you real-time power-loss notification — invaluable for compliance logging and incident response. I've seen integrators miss mains failures because they forgot to include a separate UPS monitoring device; the AL400ULXB2 bakes that in.
- 115VAC Input at 3.5A Max: Modest wall-outlet footprint. You can safely run this on a shared 15A circuit with other low-draw devices in a small lobby or utility closet, though I always isolate it for future expansion and code compliance.
Deployment Considerations:
- The 0°C to 49°C operating window excludes unheated or non-ventilated outdoor cabinets. If you're mounting this in a rooftop comms box or an uninsulated stairwell, verify ambient temperature profiles and budget for thermal conditioning or relocation indoors.
- Battery sizing is your responsibility. The charger doesn't specify a maximum connected capacity — I typically spec 7–12 Ah lead-acid for medium-sized installations and validate charge current at the battery manufacturer's datasheet to avoid trickle-charge starvation on larger packs. Undersizing the battery leaves you vulnerable to brief mains blips that drain the battery faster than the charger can replenish it.
Position the AL400ULXB2 as the backbone of any access control or alarm system that needs deterministic backup power without complexity. It's a workhorse for integrators who need codec flexibility (voltage selector), built-in battery management, and UL compliance in one board. Pair it with a 12 Ah lead-acid battery and a monitored entry-door setup, and you've got a fail-safe that will run 18–24 hours on battery alone — realistic for most access control egress scenarios.
