Brondi SMARTPHONE 4G Compatible Battery 3.7V 2200mAh

Brondi SMARTPHONE 4G — 3.7V Li-Polymer Replacement Battery (ICP445573P)

This 3.7V, 2200mAh Li-Polymer battery replaces the OEM ICP445573P cell in the Brondi SMARTPHONE 4G. It fits the exact footprint at 76.50 × 56.80 × 5.10mm. Swap it in when your original cell no longer holds charge through a normal day.

• Brondi SMARTPHONE 4G fit: The ICP445573P is a single-cell Li-Polymer pack with a fixed connector and BMS pinout matched to the Brondi SMARTPHONE 4G charge IC. Any cell going in must match the 3.7V nominal rail — a voltage mismatch trips the protection circuit before the phone even boots.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the bench. The BMS handled end-of-charge termination cleanly at 4.2V and the protection circuit triggered correctly at the low-voltage cutoff threshold without latching the pack into lockout.
• First cycle after installation: Disable fast charging for the first complete discharge-charge cycle. This gives the fuel gauge IC time to recalibrate against the new cell's discharge curve before high-current charging pushes into an uncalibrated state — which is the main cause of erratic percentage readings in the first few days.

Sudden shutdown at 20–30% on the replacement cell

This happens because the fuel gauge IC in the Brondi SMARTPHONE 4G was calibrated to the old cell's discharge curve. When the modem radio or display draws a burst of current, the new cell's voltage drops faster than the IC predicts — the phone sees that as a critical battery event and shuts down. One full discharge-to-cutoff cycle followed by a full charge lets the coulomb counter reset its end-point estimate. After that cycle, shutdowns in the 20–30% range should stop.

Phone warm near the battery during the first few charges

A new high-impedance Li-Polymer cell has slightly higher internal resistance than a conditioned cell. The charge IC compensates by running at a higher voltage differential, which produces more heat than usual during the first two or three cycles. This is a temporary condition — internal resistance drops as the cell conditions. If the phone becomes hot enough to be uncomfortable to hold, stop charging and let it cool to room temperature before resuming; keep the first charges on a 5W supply, not a fast charger.