Assa Abloy EG.086 Smart Lock Replacement Battery 4.5V 2400mAh

Assa Abloy EG.086 / EG.090 — 4.5V Alkaline Replacement Battery (S09517)

This is a 4.5V alkaline battery rated at 2400mAh (10.8Wh), built to the S09517 specification. It fits the Assa Abloy EG.086 and EG.090 electronic door locks, as well as the Genie BS Elektronik EK015 access control units. Same voltage, same form factor — 46 x 32 x 10.80mm — as the factory cell.

• EG.086, EG.090, and EK015 compatibility: These models share a common 4.5V battery bay with identical connector orientation and cell geometry. The lock controller draws directly from this flat-cell format — a round or AA stack will not seat correctly, regardless of voltage match.
• Bench tested on actual hardware: We cycled this cell through lock engagement and disengagement sequences on the EG.086 platform. The controller drew a short current spike on each deadbolt throw; the cell held voltage without sagging below the lock's low-power threshold throughout the test run.
• Post-install reconnection window: After swapping the battery, wait 60 seconds before testing the lock remotely. The EG.086 runs a mesh network re-join sequence after any power interruption. Triggering a remote command during that window can register as a fault in the app.

Why the EG.086 drains faster in high-traffic door scenarios

Every lock cycle — motor engagement, position sensor read, and wireless status push — pulls current from the battery simultaneously. In high-traffic entry points, these cycles compound quickly. The wireless radio in the EG.086 also polls the hub at a set interval; a shorter polling interval burns more power between lock cycles. Check your access control app for the polling or heartbeat setting and extend it if the door is not critical-path.

Low battery alert showing immediately after a fresh cell install

Alkaline cells sitting in storage lose surface charge over time, even unsealed. If the resting voltage drops below 4.2V before installation, the EG.086's controller reads it as a depleted cell and fires the alert immediately. The fix is to confirm the cell reads at or above 4.5V with a multimeter before installing. If it reads low, the cell has been in storage too long — replace it with a fresher unit.