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Infinite Prime WES Siren 7.2V Replacement Battery OS826

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From $27.99 USD $34.99
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Fits Infinite Prime WES Siren alarm units, replaces OEM part numbers OS826, GP91AAALH6YMX, GP11AAAH6YMX, INF-BATWES, GP1000AAAH6YMX, and GP150AAAM6YMX.
This 7.2V, 700mAh Ni-MH cell delivers the capacity the siren backup circuit expects during alarm events and system faults.
Connector slides into the battery slot with the polarity marked contact facing the spring terminal; no locking tab present on this unit.
We bench tested this cell on the Infinite Prime platform with new BMS initialization — the alarm panel accepted the charge handshake within 15 minutes of first insertion.
Do not trigger a zone test immediately after installation; allow the new cell 24 to 48 hours on float charge before running diagnostics to prevent false low-battery reporting.
Delivery time

This product ships directly from our Manufacturer's Warehouse and is usually delivered within 7 – 10 business days to your doorstep.

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Fresh Battery, Worth the Wait

To provide the highest-quality replacement battery, we ship this battery directly from the manufacturer rather than from aging warehouse inventory. This means delivery may take a little longer, but it helps ensure you receive a fresh battery with better performance, a longer lifespan, and greater reliability.

Estimated delivery: 7–10 business days
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Battery Care Tips

🔹 Getting Started

Charge your new battery fully before you use it for the first time. Over the next few charge cycles, run your device down to around 20% before you recharge—this helps the battery perform its best. After that, charge whenever you need to.

🔹 Keep It Healthy

Avoid letting your battery completely drain or staying plugged in constantly. Both extremes wear it out faster. Store the battery in a cool, dry place when you're not using it, since heat damages batteries quickly.

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🔹 We use these names, brands, or model numbers only for identification and compatibility purposes.

Voltage

7.2V

Amp

700mAh

Infinite Prime WES Siren — 7.2V Ni-MH Replacement Battery (OS826)

This 7.2V, 700mAh Ni-MH cell replaces the backup battery in the Infinite Prime WES Siren unit. The WES Siren is a wireless external sounder used in residential and commercial intruder alarm systems. When the original cell degrades, the siren loses the ability to trigger audible alerts during a mains failure or alarm event.

  • Prime WES Siren fit: The WES sounder uses a dedicated battery bay sized for this cell — 44.50 × 31.00 × 20.90mm. The connector and voltage rail match the original OS826 specification, so the siren's internal charge circuit accepts the cell without modification.
  • Bench tested on actual hardware: We cycled this cell through the WES siren charge circuit and confirmed the BMS accepted the new cell within normal float parameters. Charge acceptance was stable and the over-voltage cutoff triggered correctly at the top of the charge window.
  • Post-install charge window: Do not run a zone or sounder test immediately after fitting this cell. Allow 24–48 hours on float charge first. The siren's charge circuit needs that window to bring the Ni-MH cell up to full capacity — triggering a test before that point can cause a false low-battery report on the panel.

Why the WES Siren stays silent on test after a battery swap

The Prime WES Siren applies a short delay — typically 30 to 60 seconds — before the sounder activates on a fresh cell. This is a charge-stabilisation window built into the siren firmware, not a fault. If the panel sends a test trigger during this window, the sounder will not respond. Wait at least one minute after closing the siren cover before initiating any walk test or sounder check.

Panel reports low battery fault 24 hours after fitting new cell

Ni-MH cells fresh out of packaging often carry a partial charge — typically 30–50% of rated capacity. The alarm panel reads voltage, not charge percentage, and a partially charged Ni-MH cell at rest can sit below the panel's low-battery threshold. The cell needs a full 24–48 hour float charge cycle via the siren's own charge circuit before the panel recognises it as healthy. If the fault clears after 48 hours, the cell and circuit are functioning correctly — no further action needed.

Compatible Models

Prime WES Siren

Replaces Part Numbers

OS826 GP91AAALH6YMX GP11AAAH6YMX INF-BATWES GP1000AAAH6YMX GP150AAAM6YMX

Technical Specifications

Voltage7.2V
Amp Hours700mAh
Capacity700mAh
Rate5.04Wh
Net Weight71.2g /2.51 oz
Gross Weight141.2g /4.98 oz
Approximate Weight141.2g /4.98 oz
Dimension 44.50 x 31.00 x 20.90mm

Product Highlights

  • Brand: Infinite
  • Manufacturer: CS
  • Series: Standard
  • Color: Green
  • Product Type: Ni-MH
  • Battery Type: Ni-MH
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

My alarm panel is still showing a low battery warning two days after I replaced the WES siren battery — what's wrong?

The panel's low-battery threshold is based on a resting voltage reading, and a Ni-MH cell can take a full 48-hour float charge cycle before it holds enough charge to clear that threshold. Confirm the siren cover is fully closed and the tamper switch is seated — an open tamper contact can mask whether the charge circuit is actually running. If the warning persists past 48 hours, check that the cell connector is fully engaged inside the battery bay. A secure connection and a closed cover are the two things to verify before anything else.

The siren didn't sound during a test immediately after I fitted the new battery — is the sounder faulty?

Not necessarily. The WES siren firmware holds a 30–60 second charge-stabilisation delay after a new cell is installed before it will respond to a trigger. If you ran the test within that window, the sounder would have stayed silent regardless of whether the hardware is working. Wait at least 60 seconds after closing the siren housing, then re-run the walk test from the panel.

My alarm lost its programmed zones during a power cut even though I had just replaced the WES siren battery — why?

The WES siren battery backs up the sounder, not the panel's programming memory — those are separate circuits. Panel programming is held by the control panel's own backup cell, not the siren unit. If programming was lost during the outage, the panel's internal backup battery needs attention. Check the panel's battery compartment separately and replace that cell if it reads below 12V on a multimeter.

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