About this replacement
Motorola Nextel i205 / i215 Series — 3.7V Li-ion Replacement Battery (SNN5705)
This is a 3.7V, 750mAh Li-ion replacement battery for the Motorola Nextel i205, i215, i265, and i275, plus over 50 additional compatible Nextel models. It matches the OEM part number SNN5705. If your original battery no longer holds a charge or the phone shuts down unexpectedly, this cell is a direct swap.
- i200-series platform fit: The i205, i215, i265, and i275 all run on the same 3.7V single-cell architecture with the same SNN5705 connector and BMS handshake protocol. One cell spec covers the full range of these Nextel iDEN phones.
- Bench tested on actual hardware: We cycled this cell on an i205 unit and confirmed the BMS accepted the new cell without fault codes. Charge termination triggered correctly at 4.2V and the protection circuit tripped as expected under a short-load test.
- Fuel gauge recalibration after swap: On first use after installing this cell, run one complete discharge to auto-shutdown followed by a full charge before re-enabling any push-to-talk or data sessions. This lets the fuel gauge IC map the new cell's discharge curve before reporting to the OS.
Sudden shutdown at 20–30% on the Nextel i205 after a cell swap
The i205 uses a coulomb-counting fuel gauge IC that was calibrated to the original cell's internal resistance and discharge curve. When a new cell goes in, the IC is still referencing the old curve. The new cell's voltage drops faster under modem and screen load than the IC expects, so the phone hits a voltage cliff and cuts out even though the displayed percentage looks safe. One full discharge-to-shutdown cycle followed by a complete charge resets the reference curve and eliminates premature cutoffs.
Phone not powering on after the replacement battery sat in storage
Li-ion cells that self-discharge below 2.5V per cell trigger a BMS lockout — the protection circuit opens to prevent damage, and the phone appears completely dead. Plug the phone into a wall charger and leave it untouched for 20–30 minutes. The charge IC will trickle current into the cell at a low rate until the voltage recovers above the BMS re-enable threshold of approximately 2.9V, at which point normal charging resumes and the phone will power on.