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Access control power supplies

Every access control installation needs a dedicated power supply for the readers, controllers, electric strikes and electronic locks. HDWR offers AC-to-DC power supplies sized for the typical loads found in office, retail and small-business installations, including units with a battery-backup terminal so the door stays operable during a mains outage.

What to look for in an access-control PSU​

  • Output voltage — 12 V DC is the most common choice for readers, keypads, electronic locks and most electric strikes; 24 V DC is used by some heavier-duty strikes and magnetic locks
  • Current rating — sum the steady-state current of every device on the loop, then add the inrush draw of the strike or lock at the moment of release; pick a PSU rated at least 20-30% above that total
  • Battery backup — for doors that must keep working through a power outage, choose a PSU with a battery-charger terminal and add a sealed lead-acid battery sized for the desired run-time
  • Tamper / overload protection — look for short-circuit, overload and over-temperature protection; some units include a tamper switch contact you can wire into the alarm panel
  • Form factor — DIN-rail-mounted PSUs sit cleanly inside an electrical cabinet; boxed PSUs with built-in battery compartment install on a wall next to the controller

Quick sizing example​

A small installation with one HDWR proximity reader, one keypad encoder and one 12 V electric strike typically draws around 0.3 A continuous, with a momentary inrush of ~1 A when the strike releases. A 12 V 2 A PSU with a 7 Ah battery backup will run that door for several hours through a power cut without strain.

Documentation in this category​

  • Models — per-model specifications, output ratings, battery support and mounting options (see the sidebar as they are added)

Access control power supplies FAQ

What voltage do I need for my access control devices?
Most HDWR proximity readers, keypad encoders, electric strikes and electronic locks run on 12 V DC. Some heavier electric strikes and magnetic locks (mag locks rated for holding forces above ~500 kg) use 24 V DC instead. Check each device's datasheet before picking the PSU — mixing voltages on one loop requires step-down converters and is rarely worth the complexity. If every device on the door takes 12 V, pick a 12 V PSU; if any device needs 24 V, switch the whole door to 24 V.
How do I size the PSU for my installation?
Add up the continuous current draw of every device that will be powered from the PSU — readers, keypads, controllers, locks and strikes. Then look at the inrush current of the strike or lock at the moment it releases (the datasheet lists this). Pick a PSU rated at least 20-30% above the sum so the unit isn't running at maximum capacity continuously, which shortens its life. A typical single-door installation with one reader, one keypad and one electric strike fits comfortably on a 12 V 2 A PSU.
What is battery backup and when do I need it?
A battery-backup PSU charges and maintains a sealed lead-acid battery connected to its terminals. When mains power fails, the PSU switches over to the battery instantly, so the access-control loop keeps working. You need battery backup whenever the door must stay operable during a power outage — fire-escape routes, server rooms with critical hardware, 24/7 facilities, sites with frequent mains drops. Size the battery in amp-hours to cover the expected outage duration: 7 Ah supports a typical single-door loop for 6-10 hours.
Can I connect multiple doors to one power supply?
Yes, if the total current draw stays comfortably within the PSU rating. Two doors on one PSU is common for small offices. For bigger installations we recommend one PSU per door (or per zone): it isolates faults — a short on one door doesn't take down the whole site — and makes maintenance and replacement easier. A single PSU per door also lets you use a smaller battery per door for backup, which is cheaper than one large central battery.
Should the PSU go in a separate enclosure or next to the controller?
For wall-mounted single-door installations, the boxed PSU with built-in battery compartment is the simplest choice — one wall box, one wiring run. For multi-door installations or sites with an existing electrical cabinet, the DIN-rail variant is cleaner: it fits beside the access controller and the data wiring stays inside the cabinet. Either way, keep the PSU close to the controller (within a few metres) so the DC voltage drop on the supply lead stays negligible.
What protections should I look for in an access-control PSU?
At minimum: short-circuit protection (auto-resetting), overload protection, and over-temperature protection. Useful extras: low-battery warning output (sends a signal when the backup battery is failing), tamper switch contact (triggers if the enclosure is opened — wire it into the alarm panel), and surge protection on the AC mains input. HDWR access-control PSUs include the core three protections as standard; battery and tamper features depend on the model.