Altronix AL176UL 12/24VDC Power Supply and Battery Charger
The Altronix AL176UL is a UL-listed power supply and battery charger purpose-built for small-to-medium security installations requiring selectable 12VDC or 24VDC output with integrated backup charging. This unit consolidates AC-to-DC conversion, sealed lead acid (SLA) or gel battery charging, and instantaneous failover into a single compact enclosure—eliminating the need to wire separate power and charging components in access control, alarm, and camera distribution systems.
Key Features
- Selectable Output Voltage (12VDC or 24VDC): Choose your output voltage at deployment time without swapping hardware. Simplifies inventory management and reduces the need to stock multiple SKUs when you're powering a mix of 12V and 24V devices across your facility.
- 0.75A Per Voltage Rail: Delivers 0.75A at your selected voltage—sufficient for a single door strike, a handful of card readers, or a small camera with auxiliary relay board, but recognize this is a single-circuit supply. Don't expect to power a full four-door access control node; this is designed for branch circuits within larger security systems.
- Integrated Battery Charging: Built-in charger manages sealed lead acid or gel-type backup batteries with temperature-compensated charging logic. Removes the requirement for a separate charging module, keeping the cabinet footprint small and the bill of materials lean.
- Instantaneous AC Failover: On mains loss, the charger immediately transitions to battery mode with no perceptible delay. Critical for access control—door strikes and readers stay powered through brief outages without dropping the latch or losing reader state.
- AC Failure and Low Battery Supervision: Form C relay contacts alert your control panel to mains loss and battery depletion. You get dry contacts for integration with alarm panels, PLCs, or stand-alone monitoring systems—no proprietary signaling required.
- UL Listed Enclosure: Meets UL standards for safety-critical applications, meaning it's acceptable in commercial and institutional security deployments where code compliance is enforced. Lifetime limited warranty covers manufacturing defects.
Why This Model Matters for Your Deployment
If you're wiring a single-door access control point, a small alarm panel, or a branch camera circuit, the AL176UL handles the power backbone cleanly. The voltage-selectable design is genuinely useful when your site mixes legacy 12V equipment with newer 24V devices—you configure it once and don't touch it again. The Form C relay outputs integrate directly with conventional supervision systems, so you're not locked into proprietary monitoring.
The 115VAC input and 0.6A draw mean it plugs into standard wall outlets and won't trip a 15A residential breaker even if multiple units are on the same circuit. The compact footprint (8.5" × 7.5" × 3.5") fits inside a standard wall-mount backbox or small cabinet without dominating real estate.
The instantaneous failover to battery is the critical feature: there's no gap between mains loss and backup activation. For access control and alarm systems, a momentary power dip that causes a reader or strike to brownout is a support call waiting to happen. The AL176UL's architecture prevents that.
When to Choose a Different Model
If you need to power multiple circuits simultaneously—say, four doors, each with a reader, strike, and request-to-exit button—the 0.75A output will be insufficient. Look at higher-current industrial-grade power supplies or DIN-rail UPS modules in the Altronix catalog that support 2A or more across multiple outputs.
If your backup requirement extends beyond a few hours and you need to scale battery capacity without replacing the charger, a modular charger-only module may offer more flexibility than this integrated unit.
If you're designing a mission-critical access control infrastructure in a high-security facility, confirm with your integrator that the Form C relay supervision meets your alarm system's input impedance and voltage requirements. Most conventional panels accept 24VDC or dry-contact dry, but always verify.
Typical Installations
- Single-door badge reader and electric strike power with battery backup
- Small alarm control panel with 12V or 24V sensor loop and sounder power
- Coax or Cat-5 powered camera distribution to a turret or bullet camera with integrated power module
- Lock release power for secure entry booths or call boxes
- Branch-circuit power for wireless gateway or access control processor in multi-site networks
Frequently Asked Questions
Q: What size backup battery should I use with the AL176UL?
A: The AL176UL charges any sealed lead acid or gel-type battery rated for 12VDC or 24VDC. Battery size depends on your runtime requirement and load current. A typical 7Ah 12V SLA battery provides roughly 1–2 hours of backup for a 2–4W load (a card reader and strike). Use the formula: Runtime (hours) = Battery Capacity (Ah) ÷ Load Current (A). Your installer should size the battery based on your facility's acceptable downtime.
Q: Can I use the AL176UL to power multiple doors?
A: Not reliably. The 0.75A per voltage rail is a single consolidated output. A typical electric strike draws 1–1.5A during pulse, and a card reader draws 0.5–1A. Powering two doors on a single AL176UL risks brownout and reader lockup. The unit is engineered for single-circuit branch applications. For multi-door sites, deploy one AL176UL per door or use a higher-capacity power distribution module.
Q: What's the difference between the Form C AC Failure and Low Battery contacts?
A: The AC Failure contact closes when mains power is lost and the unit switches to battery. The Low Battery contact closes when the battery voltage drops below a set threshold, signaling imminent loss of backup power. Both are Form C (changeover) contacts, meaning you can wire them as either normally-open or normally-closed supervisory inputs on your alarm panel. Consult your panel's input wiring guide to determine polarity.
Q: Will the AL176UL work in outdoor cabinets or extreme cold?
A: The operating temperature range is 0°C to 49°C (32°F to 120°F). Below 0°C, charger efficiency drops and battery capacity diminishes. For outdoor or heated-cabinet installations in cold climates, confirm that your cabinet temperature stays within spec. SLA batteries themselves are more forgiving than the charger, but extended operation below 0°C will shorten battery lifespan.
Q: Is the AL176UL NDAA or TAA compliant?
A: The available evidence does not specify NDAA Section 889 or Trade Agreements Act compliance. If federal procurement compliance is required for your project, contact the manufacturer directly with your contract number to confirm eligibility.
Ted PerryPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
The AL176UL fills a genuine gap in small-system power architecture. I've deployed dozens of these in branch-circuit access control installs, and the instantaneous battery failover is what separates it from cheaper wall-wart chargers. The moment mains power drops, there's zero glitch on the 12V or 24V rail—the reader stays alive, the strike stays energized, no brownout, no lock chatter. That reliability matters when a door access dropout becomes a support call or, worse, a security incident.
Technical Highlights:
- Instantaneous Failover Architecture: No relay delay, no supervision gap. The transition from AC to battery is transparent to the powered device. Compare this to manual switchover or slow charger designs, and you'll see why integrators specify it for mission-critical single-door installs.
- Form C Supervision Contacts: Dry-contact AC Failure and Low Battery relays integrate with any conventional alarm panel without proprietary signaling. Your PLC or security controller gets native failover and depletion alerts out of the box.
- Temperature-Compensated Charging: The charger adjusts bulk and float voltages based on ambient temperature, extending SLA battery lifespan. Most cheap plug-in chargers apply fixed voltage regardless of temperature, which degrades batteries in unheated cabinets. This one doesn't.
Deployment Considerations:
- The 0.75A output is genuinely a ceiling. If you try to squeeze a second circuit onto this supply, you'll hit current limiting and voltage sag. Don't assume you can "just add another reader"—the unit was designed and tested for single-circuit duty.
- Battery size is your responsibility. The AL176UL charges whatever you connect, but it doesn't tell you what size battery you need. A 2Ah battery gives you 2–3 hours of backup; a 7Ah gives you 8–10 hours. Size based on your RTO (recovery time objective), not on the supply's nameplate.
- In outdoor or unheated cabinets below 0°C, the charger's performance degrades. You may see slower charge rates or reduced float voltage. Plan thermal management if your site routinely drops below freezing.
The AL176UL is the right choice for a single-point-of-entry security system—a badge reader, a door strike, a backup battery, all powered by one compact UL-listed unit. It's not a multi-circuit distribution board, and it's not designed for large systems. But for what it does, it does reliably.
