BL-5V Vertu Constellation Replacement Battery 3.7V 900mAh

Vertu Constellation / RHV-8 / RM-267v — 3.7V Li-ion Replacement Battery (BL-5V)

This is a 3.7V, 900mAh (3.33Wh) Li-ion replacement cell for the Vertu Constellation, RHV-8, and RM-267v. It slots into the same physical bay as the original BL-5V and connects to the same charge IC and fuel gauge circuit. If your original cell has swollen, dropped capacity, or stopped holding a charge, this is the direct replacement.

• Constellation, RHV-8, and RM-267v compatibility: All three models share the same BL-5V footprint, connector pinout, and 3.7V nominal rail. The BMS on each device communicates with the cell over the same two-wire interface, so no firmware or hardware difference affects fitment across this group.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Constellation platform and confirmed the BMS accepted the cell without cutoff errors, the charge IC reached full termination voltage, and the protection circuit tripped correctly at low-cell threshold.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. The fuel gauge IC on the Constellation was calibrated to your old cell's discharge curve. Letting it run one slow cycle against the new cell gives the coulomb counter accurate reference points before any high-current charging begins.

Sudden shutdown at 20–30% on the replacement cell

The Vertu Constellation's fuel gauge IC stores a learned discharge curve from the original cell. When a new cell goes in, that stored curve no longer matches actual cell chemistry, so the IC misreads remaining capacity. Under load — screen at full brightness, active call, or data sync — the cell voltage drops faster than the gauge expects, triggering a hard shutdown before the displayed percentage reaches zero. One full slow discharge down to automatic cutoff, followed by an uninterrupted charge to 100%, forces the coulomb counter to relearn the new cell's voltage-capacity relationship. After that cycle, shutdowns at 20–30% stop.

Phone warm near the battery compartment during the first few charges

A new Li-ion cell has slightly higher internal impedance than a broken-in one, and the Constellation's charge IC applies a fixed charge current regardless. Higher impedance means more energy is dissipated as heat during the CC phase — this is normal for the first two to three cycles and decreases as the cell's impedance drops with use. If warmth continues beyond the third charge cycle or the case becomes hot to the touch, check that the battery contacts are fully seated and no debris is under the cell. Charging should stabilise at a surface temperature well below 40°C by cycle four.