POSH Titan HD B01-E500 Replacement Battery 3.8V 2000mAh

POSH Titan HD / E500A — 3.8V Li-ion Replacement Battery (B01-E500)

This is a 3.8V Li-ion cell rated at 2000mAh (7.6Wh), built to the B01-E500 specification. It fits the POSH Titan HD and E500A smartphones. Swap it when the original cell no longer holds a usable charge or shuts down unexpectedly under load.

• Titan HD and E500A compatibility: Both the Titan HD and E500A share the same physical footprint and connector pinout. The cell dimensions — 72.05 × 57.01 × 4.35mm — match the battery bay on both variants, and the BMS communicates over the same two-wire interface the board expects.
• Bench tested on actual hardware: We cycled this cell through full charge and load discharge on the E500A board. The BMS held cutoff at the correct lower voltage threshold and accepted charge current without tripping the protection circuit.
• Fuel gauge recalibration on first cycle: After fitting this cell, disable fast charging and run one full discharge down to automatic shutdown, then charge uninterrupted to 100%. This gives the fuel gauge IC one clean reference cycle against the new cell's discharge curve before it starts reporting percentages to the OS.

Sudden shutdown at 20–30% on the replacement cell

This happens because the fuel gauge IC is still using the old cell's voltage-to-capacity curve. A new cell has a steeper voltage cliff near the bottom — when the phone pulls current for the modem or display, voltage drops fast and the protection circuit cuts power before the OS sees 0%. One full discharge-charge cycle resets the coulomb counter and maps the new curve correctly. After that cycle, shutdowns at 20–30% should stop.

Phone not powering on after the replacement cell sat in storage

Li-ion cells self-discharge during storage. If the cell voltage dropped below roughly 2.5V, the BMS enters lockout and will not pass current to the board — the phone shows no response even on charge. Connect the phone to a wall adapter and leave it untouched for 15–20 minutes before attempting to power on. The charge IC needs to trickle current into the cell until it clears the BMS lockout threshold before normal charging resumes.