Introduction to the Ajax 12V PSU (ITM003871) and its key features
The Ajax 12V PSU (ITM003871) is a compact internal power-supply board designed to replace the factory mains PSU inside Ajax security hubs (Hub, Hub Plus, Hub 2 variants) and ReX range extenders. Its primary purpose is to allow these devices to run from low-voltage DC sources — for example automotive batteries, on-board boat power systems, portable battery packs and other 12V installations — instead of using the standard 110/230V mains adapter. This simple but versatile accessory expands deployment options for Ajax systems, enabling secure alarm operation in mobile, off-grid or unstable-mains environments.
- DC input capability:Runs from common 12V DC sources (typical variants accept 8–20 V DC; some variants support up to 32 V DC).
- Designed for Ajax hubs and ReX:Compatible with Hub, Hub Plus, Hub 2 (2G/4G) variants and ReX / ReX2 — verify compatibility for your generation.
- Onboard protection:Includes turn-on/turn-off thresholds and protection to safeguard the hub and attached accessories from incorrect voltages.
- Compact, installer-ready:Small board form factor with terminal adapter included for direct wiring to the hub’s power socket.
- Accessory for trained installers:Supplied with a quick-start guide; installation inside the enclosure is recommended to be performed by a qualified technician.
Detailed specifications and benefits
The Ajax 12V PSU is a focused solution: it replaces the internal mains power board and provides regulated DC power to the hub or extender. Understanding the specifications helps determine whether it suits your specific deployment.
- Input voltage:Commonly 8–20 V DC; some labelled variants accept up to 8–32 V DC. Always check the unit label before installation to confirm the exact input range.
- Input current:Up to 1 A, sufficient for the hub and moderate accessory loads.
- Turn-on / turn-off thresholds:Turn-on is approximately 8 V DC (±2.5%), while turn-off typically occurs around 6.9–7.5 V DC depending on load. These thresholds protect the hub from undervoltage conditions and help preserve connected batteries.
- Output voltage:Approximately 4.65–4.8 V DC (variant dependent) — tailored to supply the hub electronics correctly after the internal regulation chain.
- Output current capability:Up to 1.5 A to handle the hub and modest accessory draw.
- Form factor:Compact PCB board designed to sit inside the hub/ReX enclosure; dimensions and exact layout vary by variant (examples include 98 × 70 × 17 mm or 138 × 64 × 13 mm — check the label).
- Connectors:Uses a 5.5 × 2.1 mm male jack for the hub power input; a terminal adapter (fits 6.5 × 2 mm slot) is included for secure DC wiring.
- Operating environment:Temperature range −10 °C to +40 °C and up to 75% non-condensing humidity.
- Weight & package:Approximately 26–30 g. Package includes the PSU board, terminal adapter and a quick-start guide.
- Flexibility:Enables operation from a wide range of DC sources so alarms work where mains are unavailable or unreliable.
- Reliability:Onboard voltage thresholds and protection reduce the risk of damage from improper battery levels or spikes.
- Compactness:Internal replacement avoids external clutter and maintains the neat installation of Ajax devices.
- Installer-friendly:Terminal adapter and clear labelling make wiring straightforward for trained technicians.
Use cases and scenarios where the Ajax 12V PSU excels
This PSU opens up multiple practical scenarios beyond a standard indoor mains installation. Below are common and high-value use cases:
- Security hubs on boats, yachts and marine vessels: Many boat systems run on 12V batteries; replacing the mains PSU with this board allows Ajax hubs to integrate seamlessly with on-board power.
- Vehicle-based deployments: Service vehicles, caravans or security vans that require alarm functionality while in motion or away from AC power can benefit.
- Remote properties, cabins or temporary sites where mains are absent or intermittent can run the Ajax hub from batteries or solar-backed systems.
- Unstable mains supply installations: In locations with frequent power cuts, a DC source (battery or UPS) provides continuous alarm operation without relying on fragile mains adapters.
- Events, construction sites and temporary venues often need short-term security installations. The DC PSU enables quick deployment using portable battery packs.
How it compares with similar products on the market
There are a few categories of alternative approaches: external DC adapters, integrated UPS solutions and custom wiring kits. The Ajax 12V PSU has advantages and trade-offs versus each.
- Internal replacement (Ajax 12V PSU):Keeps installations tidy with no additional external dongles, reduces exposed wiring and uses the hub’s original power path. It is designed specifically for Ajax devices, so it integrates cleanly.
- External DC adapters:Easier to fit by non-technical users but require space and may be less secure or weatherproof. They can be more flexible for multi-device use but often need bespoke connectors and can clutter the installation area.
- Internal DC PSU:Focuses on enabling DC power input. It does not replace a full uninterruptible power supply (UPS) system but pairs well with a battery or UPS in the DC circuit.
- Integrated UPS modules:Provide seamless switchover and battery management but are typically bulkier, more expensive and sometimes require specific case modifications. For many use cases, the Ajax 12V PSU plus a dedicated battery offers a cost-effective solution.
- Compatibility with multiple Ajax hub and ReX generations and the inclusion of an installer-friendly terminal adapter make this product a direct, low-cost option for DC operation.
- The built-in turn-on/turn-off thresholds tailored to hub requirements reduce risk compared with ad-hoc DC wiring that lacks smart undervoltage protection.
Customer feedback and installer notes
While this product is primarily targeted at trained installers, feedback from professional installers and integrators highlights a few recurring themes:
- Installers appreciate the compact board design and included terminal adapter — these reduce installation time and avoid the need for custom connectors.
- Where used on vehicles and marine installations, the clear voltage thresholds and onboard protection are praised for preventing accidental damage when connecting to variable DC systems.
- Customers note the value proposition: a modest accessory cost delivers the flexibility to deploy Ajax hubs in many otherwise unsuitable environments.
Note: Always follow official Ajax installation guides and local electrical safety rules. This accessory is intended for use by trained installers; improper installation or use with incorrect voltage variants can damage the hub.
Conclusion: Why the Ajax 12V PSU (ITM003871) is a strong choice
If you need to run an Ajax hub or ReX extender from a DC source, the Ajax 12V PSU is a targeted, cost-effective and reliable accessory. It lets you move away from reliance on the mains adapter while preserving the hub’s original internal power path and safeguarding the device with built-in thresholds and protections. Whether you are securing a boat, vehicle, remote cabin, temporary site or an installation with unreliable mains, this board expands the practical use of Ajax alarm systems.
Before installation, check the PSU label for the exact input-range variant, power requirements and applicable CE/UKCA markings. When fitted by a qualified installer and paired with appropriate batteries or a UPS, the Ajax 12V PSU provides a neat, integrated and dependable DC power solution for Ajax hubs and ReX extenders.
