About this replacement
Samsung Gear S / Galaxy Gear S R750 — 3.7V Li-Polymer Replacement Battery (EB-BR750ABE)
This 3.7V, 170mAh Li-Polymer cell replaces the original EB-BR750ABE battery in the Samsung Gear S smartwatch. It fits the SM-R750V, SM-R750R4, and all variants in the Galaxy Gear S R750 line. Dimensions are 30.60 × 27.80 × 3.48mm — matching the curved cell bay in the original chassis.
- R750 platform fit: The SM-R750 series shares a single battery bay spec across carrier variants — Verizon (SM-R750V), US Cellular (SM-R750R4), and unlocked units. The connector pinout and BMS handshake are identical across all, so one cell covers the full line.
- Bench tested on actual hardware: We cycled this cell through the R750 charge controller and confirmed the BMS accepted the new cell without fault flags. Charge acceptance and cutoff voltage at 4.2V both matched factory spec.
- Post-swap charge requirement: After fitting this cell, place the watch on its magnetic charger immediately and charge to 100% before use. The fuel gauge IC on the R750 loses its reference point when the cell is swapped and cannot recalibrate without a full charge cycle from near-zero.
Why the Gear S shows 0% immediately after a battery swap
The R750 uses a coulomb-counting fuel gauge IC that tracks charge state relative to a stored reference. When you remove the old cell, that reference resets to zero. The watch reports 0% because the IC has no data on the new cell's actual state of charge. Placing the watch on the charger right after reassembly lets the IC run a full calibration sweep from near-empty to 4.2V. After one complete charge cycle, the percentage readout stabilises and tracks accurately.
Gear S draining to empty within a single day after swap
If the watch drops to zero within a day, the most common cause is the always-on display combined with continuous heart rate monitoring running simultaneously — both were likely disabled on the degraded original cell to conserve power. The new cell exposes full draw for the first time. Check Settings → Watch faces and turn off Always On Display if it was re-enabled automatically after the swap. Also verify HR monitoring is set to manual rather than continuous in the Samsung Health app, which cuts resting sensor current significantly.