NEON161 HTC Touch Dual 850 Replacement Battery 3.7V 1350mAh

HTC Touch Dual 850 / Neon 200 Series — 3.7V Li-ion Replacement Battery (NEON161, 35H00110-00M)

This is a 3.7V Li-ion replacement battery rated at 1350mAh (5Wh) for the HTC Touch Dual 850, Touch Dual P5310, Neon 200, and Neon 400. All four devices share the same cell footprint, connector pinout, and BMS handshake, so one part number covers the group. Physical dimensions are 65.80 × 41.15 × 7.25mm — measure your original before fitting if you are unsure.

• Touch Dual and Neon platform compatibility: The Touch Dual 850, P5310, Neon 200, and Neon 400 all run on the same voltage rail and use the same three-pin connector with identical BMS communication lines. A single cell revision covers all four because the charge IC on the motherboard negotiates the same handshake across this generation of HTC Windows Mobile hardware.
• Bench tested on actual hardware: We cycled this cell on a Touch Dual 850 mainboard and confirmed the BMS accepted the charge handshake without fault codes. The protection circuit responded correctly to both low-voltage cutoff and over-current conditions during a simulated modem-load draw test.
• Fuel gauge recalibration on first install: After fitting this cell, run one full uninterrupted discharge down to automatic shutdown, then charge to 100% without interruption. The HTC fuel gauge IC on this platform calibrates its coulomb counter against a complete discharge curve — skipping this step causes erratic percentage readings for the first several days of use.

Sudden shutdown at 20–30% on the Touch Dual and Neon series

This is a voltage-cliff failure, not a capacity failure. As a Li-ion cell ages — or before a new cell is calibrated — the fuel gauge IC reports a percentage based on a stored discharge curve rather than real-time cell voltage. When the modem fires during a call or the display backlight peaks, current draw spikes and cell voltage drops faster than the counter predicts. The phone's hardware protection triggers at the real voltage floor, cutting power while the OS still shows charge remaining. Fitting a fresh cell resolves the underlying voltage sag, but the percentage reading stays unreliable until one full discharge-charge cycle resets the coulomb counter baseline.

Phone not powering on after the battery sat in storage

Li-ion cells that discharge below approximately 2.5V per cell in storage trip the BMS into a lockout state — the protection circuit opens to prevent further discharge damage and the phone will not respond to the power button or show a charging indicator. Connect the device to a wall charger rather than a PC USB port, which delivers consistent 5V at higher current. Leave it connected for 20–30 minutes without pressing anything; the BMS recovery circuit needs sustained input voltage to re-initialise before the main charge IC takes over. If the charging indicator still does not appear after that window, check that the charger output is at least 5V 1A — insufficient current keeps the BMS in lockout.