Altronix AL125ULX Dual-Voltage Access Control Power Supply
The Altronix AL125ULX is a compact AC/DC power supply designed for access control and emergency egress installations where mixed voltage requirements and battery continuity are non-negotiable. This unit bridges the gap between systems that demand 12VDC and those requiring 24VDC by offering selectable output from a single 115VAC input—eliminating the need to stock and manage separate supplies for different lock types, readers, or control modules.
Overview
Access control deployments often mix legacy 12VDC solenoid locks with modern 24VDC maglock or electronic latches. Rather than installing two separate supplies, the AL125ULX delivers either voltage on demand. The dual PTC Class 2 regulated outputs ensure clean, protected power to each device—PTC (Positive Temperature Coefficient) protection trips if a short circuit or overcurrent condition occurs, then automatically resets when the fault is cleared. This is far safer than a traditional fuse, which requires manual replacement and leaves the circuit dead while you locate the issue.
Built-in battery backup is critical for doors that must remain accessible during mains failure. If AC power drops, internal rechargeable batteries seamlessly maintain 12VDC or 24VDC output, keeping locks energized or de-energized as configured. Fire alarm disconnect capability allows the supply to automatically shut down when a fire alarm is triggered, essential for life-safety compliance in many jurisdictions—unlocking doors to ensure emergency egress even if access control logic fails.
AC fail supervision monitoring alerts your control panel or BMS the moment the power input fails, enabling real-time awareness of supply status without requiring a separate monitoring circuit.
Key Features
- Selectable dual voltage output (12VDC @ 1A or 24VDC @ 0.5A): Choose the voltage that matches your lock or reader hardware at setup. No separate supply swap-out if you add a different lock type later. The 1A at 12V is sufficient for typical solenoid locks; the 0.5A at 24V delivers adequate power for maglock and electronic latch applications.
- Two PTC Class 2 regulated outputs: Each output is independently current-limited and thermally protected. If one output shorts, the PTC resets automatically when the fault clears—no fuses to replace, no downtime hunting for spares.
- Battery backup with automatic switchover: During AC mains failure, internal batteries maintain voltage output continuously. Battery condition is supervised to prevent unexpected discharge.
- Fire alarm disconnect function: Integrates with standard fire alarm signals (dry contact closure) to de-energize the supply instantly. Essential for life-safety code compliance when fail-safe or fail-secure logic must override access control during emergencies.
- AC fail supervision: Dry contact closure or alarm relay signal indicates the moment AC power is lost, enabling remote or local notification to security staff and building management.
- 115VAC input: Standard North American mains—no step-down transformer needed. Compact form factor fits standard wall-mounted enclosures or DIN rail mounting in electrical cabinets.
Integration & Compatibility
The AL125ULX is vendor-neutral: it supplies DC power to any door lock, maglock, electronic strike, or card reader hardware that operates on 12VDC or 24VDC. Integrate with any access control panel (Salto, Axis, HID, Lenel, etc.) via hardwired relay contacts for fire alarm disconnect and AC fail supervision. Pair with any backup battery system that accepts 12V or 24V trickle-charge input for extended runtime scenarios.
When to Choose a Different Model
If your application requires higher current capacity—multiple locks or extended runtime—consider larger capacity models in the Altronix power supply family that deliver higher amperage at each voltage. If you need 220VAC input for international installations, verify local availability before ordering this 115VAC-only unit. If your emergency lighting or other loads exceed 1A at 12V (or 0.5A at 24V), calculate total current draw and confirm the AL125ULX meets your peak demand.
Frequently Asked Questions
Q: Can I run two door locks simultaneously on the AL125ULX?
A: Yes, if your total current draw does not exceed 1A at 12VDC (or 0.5A at 24VDC). A typical solenoid lock draws 0.5–0.8A at 12V. Two locks in parallel would approach or exceed 1A. Calculate your lock's current draw from its datasheet and total all devices on the output before installation.
Q: What happens if the battery runs down during extended power loss?
A: Once the battery is discharged, the AL125ULX cannot supply power. Battery capacity and runtime depend on your specific load and battery size. Size the battery separately to meet your site's required hold-up time (typically 24 hours minimum for commercial access control). The AL125ULX provides trickle-charge to the battery when AC is present; the battery itself is customer-supplied.
Q: Is the AL125ULX compliant with fire safety codes?
A: The fire alarm disconnect function allows the unit to be integrated into emergency egress systems. However, compliance with local or national fire codes (NFPA 101 Life Safety Code, IBC, etc.) is a system-level design question—consult your fire safety engineer or authority having jurisdiction (AHJ) before finalizing your installation.
Q: Can I use the AL125ULX for a 24VDC maglock application?
A: Yes. Set the output selector to 24VDC and confirm the maglock's current draw does not exceed 0.5A. Many electromagnetic locks (600 lbs holding force and up) operate at 24VDC with draw under 0.5A, making this unit suitable. Verify your specific maglock datasheet.
Q: What warranty does the AL125ULX include?
A: Altronix provides a Lifetime Limited Warranty on equipment. Confirm specific terms and coverage scope with the supplier or manufacturer documentation.
Jerry TildsenPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
The AL125ULX strikes a practical balance for mixed-voltage access control sites where you cannot afford a mains failure to lock users inside or outside. The selectable 12VDC / 24VDC output and built-in battery backup eliminate the need for two separate power supplies and external battery chargers, which cuts both cost and enclosure real estate. The fire alarm disconnect is not a marketing afterthought—it's a genuine safety mechanism that ties power sequencing to life-safety logic, which integrators often overlook until an AHJ inspection catches it.
Technical Highlights:
- Dual voltage selection (1A @ 12VDC or 0.5A @ 24VDC): Eliminates the SKU sprawl of stocking separate supplies for different lock technologies. A typical solenoid lock draws 0.6A at 12V and a smaller maglock draws 0.4A at 24V—both fit cleanly within the AL125ULX's limits, so you configure once and deploy flexibly.
- PTC Class 2 protection on both outputs: Automatically limits current and thermal shutdown if a short occurs. Unlike fused supplies where a blown fuse leaves you dead on-site, PTC resets automatically when the fault clears. In a 24/7 access control scenario, automatic recovery versus manual fuse replacement is the difference between a 2-minute restart and a service call.
- Built-in battery backup with trickle charge: Maintains voltage during AC failure so locked-out users can still access or egress as configured. Battery sizing is your responsibility, but the AL125ULX handles continuous trickle charge and switchover logic internally—no separate charger module required.
- Fire alarm disconnect and AC fail supervision: Dry contact outputs keep your control panel aware of mains status and allow hardwired integration with fire alarm or emergency egress logic. This is not a nice-to-have in life-safety applications—it is a requirement.
Deployment Considerations:
- Current capacity is the primary constraint. At 12VDC, you get 1A total; at 24VDC, you get 0.5A total. If you are running two locks and a reader on the same supply, add up their peak current draw from datasheets. Exceeding rated current will trip PTC protection.
- Battery sizing is separate and non-obvious. A discharged battery provides zero runtime. Size the external battery (customer-supplied) to hold up your locks for the minimum duration required by your facility's emergency procedure—typically 24 hours minimum for commercial access control. The AL125ULX provides the charging circuit; you provide the amp-hours.
- Fire alarm integration requires a dry contact signal from your fire panel (or emergency evacuation button). Verify your fire system can close a relay contact and that your access control design specifies whether locks should fail-safe (unlock on alarm) or fail-secure (lock on alarm). This is a system design decision, not a product feature.
The AL125ULX is the right fit for multi-tenant office buildings, industrial access gates, or emergency egress scenarios where you need voltage flexibility, battery continuity, and fire alarm integration without bloating your electrical cabinet with separate supplies. Skip it if your site is single-voltage or has unlimited power budget—but in space-constrained or mixed-technology deployments, it simplifies the power story considerably.
