About this replacement
Samsung Galaxy Watch 6 44mm — 3.8V Li-Polymer Replacement Battery (EB-BR945ABY)
This 3.8V, 410mAh lithium-polymer cell is a direct swap for the original battery in the Samsung Galaxy Watch 6 44mm. It fits SM-R940 and SM-R945 variants. Swap it in when the original cell no longer holds charge through a full day of normal use.
- SM-R940 and SM-R945 compatibility: Both variants use the same physical cell footprint, connector pinout, and BMS handshake. The EB-BR945ABY is the OEM reference for both, so one replacement cell covers either model without modification.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the Watch 6 platform. The BMS accepted the new cell without flag or error, and the fuel gauge IC re-initialised correctly after a full charge cycle from near-zero.
- Post-swap first charge: After fitting the new cell, place the watch on its magnetic charger immediately and charge to 100% before first use. The fuel gauge IC on this platform cannot set an accurate state-of-charge reference without a complete charge cycle from near-zero following a cell swap. Skipping this step causes the watch to report incorrect battery percentages for days.
Always-on display and continuous heart rate monitoring on a 410mAh cell
The Galaxy Watch 6 44mm runs its AMOLED display, BioActive sensor, and Bluetooth stack simultaneously. With always-on display enabled alongside continuous heart rate monitoring, the combined draw can stress a degraded original cell noticeably. A fresh 410mAh cell restores the headroom the platform expects. If drain still seems heavy after the swap, check whether continuous heart rate mode is on — that sensor alone adds a steady background current load.
Watch not pairing after battery replacement
Removing the battery kills the active Bluetooth session between the watch and your phone. The phone holds a stale connection record and the watch starts fresh with no session reference — they can't find each other automatically. This is not a fault with the replacement cell. Open the Galaxy Wearable app on your phone, forget the watch, then re-pair from scratch. Once paired, confirm the watch charges past 3.9V on the magnetic charger to verify the new cell and charge contacts are seated correctly.