Ajax Hub Replacement Battery, 3.7 V 2000 mAh (Internal)

With a nominal voltage of 3.7 V and a capacity of 2000 mAh (2 Ah), this lithium-based cell is intended specifically for devices such as Hub, Hub Plus, Hub 2, ReX and ReX2. It is sold as a direct internal replacement (not a general-purpose battery) and is available in two connector variants (2‑pin or 3‑pin), so verifying your hub’s manufacture date and connector type before purchase is essential.

• Nominal voltage:3.7 V
• Capacity:2000 mAh (2 Ah) for reliable standby time
• Chemistry:Rechargeable lithium (Li‑ion / Li‑polymer style)
• Compatibility:Designed for Ajax Hub series and ReX extenders
• Connector options:2‑pin or 3‑pin — confirm before ordering

Detailed specifications and benefits

This replacement battery is engineered for intruder‑alarm equipment, prioritising long shelf life, slow self‑discharge and stable performance over many charge cycles. The key specifications translate into several practical benefits:

• Nominal voltage: 3.7 V — matches the original specification for Ajax hubs.
• Capacity: 2000 mAh (2 Ah) — provides sufficient reserve for typical standby and short outage scenarios while maintaining compact size.
• Chemistry: Rechargeable lithium (Li‑ion / Li‑polymer style) — high energy density and predictable discharge characteristics suited to security hardware.
• Connector: Available in 2‑pin or 3‑pin variants — ensure compatibility with your specific hub model before purchase.
• Intended use: Internal replacement for Ajax control hubs and ReX extenders — not intended as a universal power cell.

• Reliable backup power: Restores the hub’s ability to operate during power interruptions, helping maintain alarm monitoring and communications with sensors.
• Designed for security use: Lower self‑discharge and predictable voltage behaviour make it better suited to alarm control equipment than generic consumer cells.
• Compact, OEM‑style fit: The internal form factor and connector options allow a neat replacement without modification when the connector type is matched.

Use cases and scenarios where this battery excels

• Over time, all rechargeable batteries lose capacity. When an Ajax hub shows reduced backup runtime, frequent low battery alerts or fails to remain on during brief outages, replacing the internal pack with a compatible 3.7 V 2000 mAh unit is the recommended remedy.

• If the original battery has swollen, failed, or been damaged by improper charging, swapping in a new, correctly specified pack restores the hub’s resilience and reduces false alarms or unexpected shutdowns.

• Installers and system integrators can include battery replacement as part of routine maintenance cycles for multi‑site deployments, ensuring hubs remain on line and compliant with service level expectations.

• Home users and DIY installers who are comfortable with small electronics replacements can extend the life of their Hub or ReX unit without replacing the entire system — provided they confirm connector type and follow safety guidance.

Comparisons with similar products in the market

Generic off‑the‑shelf lithium cells (e.g., 18650 or pouch cells sold for hobby projects) may offer similar voltage and capacity, but they often require modification, soldering or connector changes that void manufacturer guidance.

Some aftermarket sellers offer higher‑capacity replacements. While a higher Ah rating can extend runtime, it can also change charging behaviour and thermal characteristics. Choosing a much larger cell should be done only with a full understanding of the hub’s charging circuit and thermal design.

Official or recommended replacements often come with clear documentation and compatibility notes. Third‑party, low‑cost cells may lack this support.

Installation, safety and best practice

Replacing an internal battery in a security hub requires care. Basic best practices include isolating mains power, following Ajax’s published replacement instructions, handling the battery gently (do not puncture or short), and disposing of the old battery at an authorised recycling point in line with UK/EU regulations. If you are unsure about compatibility or the replacement process, contact Ajax support or hire a qualified installer.

It offers the right balance of capacity, chemistry and form factor for security equipment, and it is available with the connector options needed to suit different hub production runs. For homeowners, DIY installers and professional contractors wanting to extend system life rather than replace the entire control unit, this battery presents a practical path to renewed reliability.