About this replacement
Motorola A955 Droid 2 — 3.7V Li-ion Replacement Battery (BP7X)
This is a 3.7V, 1600mAh Li-ion replacement battery for the Motorola A955 Droid 2 smartphone. It also fits the Cliq MB200, Droid A855, and 48 additional Motorola handsets sharing the BP7X form factor. OEM part numbers BP7X, SNN5875A, and SNN5875 all reference this same cell.
- Cross-model BP7X platform: These Motorola handsets share a common 3.7V single-cell architecture, the same physical footprint (50.00 × 45.60 × 6.80 mm), and an identical connector pinout. The BMS handshake uses the same thermistor line across all BP7X-compatible devices, so one cell services the full compatibility list.
- Bench tested on actual hardware: We cycled this cell through full discharge and charge on the A855 platform. The BMS held charge termination correctly at 4.2V and the protection circuit tripped at the expected low-voltage cutoff without triggering a hard lockout.
- First-cycle fuel gauge reset: After installation, disable fast charging and run one complete discharge down to automatic cutoff, then charge fully without interruption. The fuel gauge IC on these Motorola handsets calibrates its coulomb counter against the new cell's actual discharge curve on that first full cycle.
Why the Droid 2 reports wrong battery percentage after a cell swap
The fuel gauge IC on the A955 stores a discharge curve model built up from the previous cell's charge history. When a new cell goes in, that stored model no longer matches the actual cell chemistry, so the percentage readout drifts. The IC needs a full uninterrupted discharge-to-charge cycle to rewrite its internal model against the new cell. Until that cycle completes, percentage jumps of 5–15% are normal and not a fault with the battery.
Sudden shutdown at 20–30% on the replacement cell
This happens when the modem radio or display triggers a brief high-current draw and the cell voltage sags below the BMS cutoff threshold — even though the fuel gauge still shows charge remaining. On a freshly installed cell, the fuel gauge IC has not yet mapped where the actual voltage cliff sits on this cell's curve. Run the first full discharge cycle without heavy background sync or screen-on sessions to give the IC accurate data. After one calibrated cycle, the reported percentage and the real voltage cliff align, and the shutdowns stop.