Altronix AL624 Selectable Voltage Linear Power Supply Board
The Altronix AL624 is a compact linear power supply board engineered for integration into access control systems, alarm panels, and security infrastructure where regulated DC power and battery backup failover are non-negotiable. The AL624 accepts 16/24VAC input and outputs user-selectable DC voltage—6VDC, 12VDC, or 24VDC—with integrated sealed lead acid or gel battery charger and instantaneous switchover upon AC loss. Board dimensions measure 2.5" × 3" × 1.5", making it suitable for OEM integration and retrofit into existing enclosures without major redesign.
Key Features
- Selectable Output Voltage (6/12/24VDC): Choose the voltage your system needs without stocking multiple supply designs. Common in access control (24VDC for locks and controllers), low-voltage alarm panels (12VDC), and auxiliary security circuits (6VDC for sensors or relays). This flexibility reduces SKU inventory and simplifies field deployment across mixed-voltage installations.
- 16/24VAC Input Compatibility: Standard transformer secondary voltages commonly available in security installations. This input range maps directly to existing branch circuits or dedicated transformer outputs, eliminating the need for step-down or step-up conversion.
- Integrated Battery Charger with Instantaneous Failover: The AL624 continuously charges sealed lead acid or gel-type batteries (the most widely deployed chemistries in access control backup systems) and switches to battery power in <1 millisecond if AC drops. No software polling, no relay logic, no delay—this matters when a door lock or access reader must remain powered through a brownout or blackout. You choose the battery capacity; the charger handles float charging automatically.
- Current Delivery Scaled by Voltage: Maximum output current is 0.2A at 6VDC, 0.2A at 12VDC, and 0.75A at 24VDC. The 24VDC variant delivers 3.75× the wattage of the 6VDC option, making it suitable for powering multiple door strikes, magnetic locks, or access control panels on a single board. At 12VDC and below, capacity is tighter—size your load accordingly or parallel boards if higher current is needed.
- Compact Board Form Factor: At 2.5" × 3" × 1.5", the AL624 mounts directly to a mounting rail or wall inside a control enclosure. No separate external chassis means easier integration into retrofit projects and new builds with space constraints. Thermal design assumes the surrounding enclosure provides adequate convection cooling—confirm ventilation in hot environments (operating range: 0°C to 49°C / 32°F to 120°F).
- Linear Regulation Architecture: Linear supplies are inherently noise-free and generate minimal electromagnetic interference—an advantage when the power supply shares an enclosure with low-level signal wiring (door sensors, card readers) or analog alarm circuits. The tradeoff is lower efficiency and more heat output compared to switching supplies, but in a thermally managed enclosure this is usually acceptable for the EMI benefit.
Integration & Compatibility
The AL624 is a bare board component designed for OEM integration, system build-outs, or retrofit mounting inside existing security control enclosures. It requires a 16/24VAC transformer input (confirm your building power or existing transformer can supply this), a sealed lead acid or gel battery for backup (not included), and output wiring to your loads (door locks, readers, relay circuits). Voltage selection is user-configurable via on-board switching or jumpers—refer to the product datasheet for the specific configuration method.
Typical applications include emergency lighting circuits, access control reader power backup, magnetic lock failsafe power, alarm panel auxiliary supplies, and fail-secure/fail-safe solenoid circuits. Confirm your system's voltage and current requirements before ordering; undersizing current capacity is a common integration mistake.
Operating Environment
Rated for 0°C to 49°C (32°F to 120°F) operation. This range covers most indoor control room and cabinet deployments but excludes uninsulated outdoor or freezer environments. If you're installing in a non-temperature-controlled space, verify that your enclosure and charging circuit can maintain this thermal window. The AL624 is not outdoor-rated and should be mounted inside a weatherproof enclosure if exposed to moisture.
Warranty
The AL624 carries Altronix's Lifetime Limited Warranty, which covers defects in materials and workmanship. Review the warranty documentation for terms regarding battery charger maintenance and exclusions.
Frequently Asked Questions
Q: Can I use the AL624 with a lithium or AGM battery instead of sealed lead acid?
A: The AL624 is designed and tested for sealed lead acid and gel-type batteries. Lithium or AGM batteries have different charge curves and voltage profiles. Using an incompatible battery type may damage the charger or reduce battery service life. Confirm battery chemistry compatibility with the manufacturer or product documentation before substituting.
Q: What happens if I exceed the maximum current rating (0.75A at 24VDC)?
A: The AL624 will experience thermal stress and may trigger internal protection or degrade output regulation. Size your load to stay within the rated current for your selected voltage. If you need higher current, consider parallel boards or a larger power supply unit.
Q: Is there a way to monitor battery status or failover events?
A: The AL624 is a passive board supply with no built-in status relay or network monitoring. For battery monitoring and event logging, you'll need to add external monitoring hardware (status relays, UPS monitoring cards, or a separate control system). Verify your enclosure design includes space and wiring for optional monitoring circuits.
Q: What VAC transformer input do I need?
A: The AL624 accepts 16/24VAC input. You will need a 16 or 24VAC transformer secondary (commonly available from electrical suppliers). Confirm your facility has a suitable AC branch circuit and transformer, or install one. This is typically a Class 2 transformer used in low-voltage security systems.
Q: Does the AL624 work with my access control panel?
A: If your panel operates on 6VDC, 12VDC, or 24VDC and draws current within the AL624's rated limits, the answer is likely yes. Verify your panel's voltage and maximum current draw. Many modern access control systems use 24VDC; older panels may use 12VDC. This board is voltage-agnostic and compatible with any 24VAC-input device requiring one of its three output voltages.
Q: Can I use the AL624 to replace a failed larger power supply?
A: Only if your current load fits within the AL624's current ceiling. A 0.2A limit at 12VDC is roughly 2.4W; at 24VDC, 0.75A is 18W. If your original supply was rated for 50W or more, the AL624 will not suffice. Confirm load requirements and select a supply with adequate current headroom.
Ted PerryPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
The Altronix AL624 is a no-frills board-level power supply that does one job well: deliver regulated DC backup power with battery failover inside a control enclosure. If you're integrating access control, alarm panels, or low-voltage security circuits and need instantaneous battery switchover without external relays or monitoring logic, the AL624 solves that. The three selectable output voltages (6/12/24VDC) mean you can configure voltage in the field without redesigning the supply board. Maximum current ratings—0.2A at 6/12VDC and 0.75A at 24VDC—set hard limits on what you can power, and that's the crucial spec to validate before committing to this board.
Technical Highlights:
- Selectable 6/12/24VDC Output: Eliminates single-voltage inventory. A 24VDC variant can deliver 18W of backup power—enough for a magnetic lock and reader circuit—while the 6VDC and 12VDC options address lower-power auxiliary loads like solenoid coils or sensor conditioning circuits.
- Instantaneous Failover (<1 ms): When AC drops, there is no software delay or relay chatter. The battery assumes the load immediately. This matters in access control where even a 10 ms power dip to a reader can cause authentication loss.
- Integrated Battery Charger: Continuous float charging of sealed lead acid or gel batteries eliminates the need for a standalone charger. Battery capacity is your choice; the AL624 manages the charge curve automatically.
- Linear Architecture with Zero EMI Penalty: No switching noise means cleaner power to low-level signal circuits (card readers, door sensors) sharing the same enclosure. Downside: more thermal dissipation than a switching supply, but inside a vented enclosure this is manageable.
Deployment Considerations:
- Current Ceiling is Firm: 0.75A at 24VDC (18W) is not negotiable. A single magnetic lock at 1.5A will overrun this supply. Verify your load current before commissioning. If you're replacing a failed supply, confirm the AL624's rated current matches or exceeds your existing load.
- Thermal Management Required: Operating range is 0°C to 49°C. Linear supplies dissipate heat proportional to the input-output voltage difference. In a sealed or poorly ventilated enclosure, the AL624 may throttle or fail. Confirm your cabinet has fan cooling or natural convection path if ambient is above 40°C.
- Battery Sizing Is Your Responsibility: The AL624 charges the battery but does not specify what capacity you need. Calculate your system's current draw, desired backup runtime (usually 4–8 hours for access control), and select a sealed lead acid or gel battery accordingly. Undersizing runtime is a field problem that emerges during the first outage.
- No Monitoring or Alarm Output: The AL624 has no status relay or network alert mechanism. If you need to know when the system is on battery, you must add external monitoring hardware. This is fine for passive backup installations but problematic if you require event logging or alarm escalation.
The AL624 excels in retrofit and OEM integration where enclosure real estate is tight and voltage flexibility is valuable. It is not suitable for high-current loads (>1A), outdoor exposed installations, or systems requiring remote battery status monitoring. For a small access control retrofit or low-power auxiliary backup circuit in a secure mechanical room, the AL624 delivers silent, predictable failover at a cost-effective price point.
