Brondi ENERGY 4G Compatible Battery 3.7V 1750mAh

Brondi Energy 4G — 3.7V Li-Polymer Replacement Battery (AHB474067P)

This 3.7V, 1750mAh (6.48Wh) lithium-polymer cell replaces the original AHB474067P battery in the Brondi Energy 4G. It fits the slim battery bay directly and connects via the standard three-pin connector used on this handset. Physical dimensions are 72.00 × 44.00 × 5.00mm — confirm these against your existing cell before ordering.

• Energy 4G fitment: The AHB474067P cell is specific to this handset's voltage rail and connector pinout. The three-pin layout carries both power and the BMS data line the phone uses for charge termination — an incorrect cell will either not charge or trip the protection circuit immediately.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the Energy 4G platform. The BMS handshake completed on first connection, charge current ramped correctly, and the protection circuit responded to over-discharge cutoff at the expected threshold.
• Fuel gauge recalibration on first use: After fitting this cell, disable any fast-charge mode and run one complete discharge-to-charge cycle before normal use. This gives the phone's fuel gauge IC time to map the new cell's discharge curve accurately before high-current charging is applied to an uncalibrated cell.

Sudden shutdown at 20–30% on the Energy 4G after a cell swap

This happens because the fuel gauge IC is still running the discharge curve it learned from the old, degraded cell. When the new cell hits a voltage point the IC associates with 20–30% remaining on the old curve, the phone reads it as critically low and shuts down — even though real capacity remains. The fix is one full uninterrupted discharge down to automatic cutoff, followed by a full charge without interruption. After that cycle, the coulomb counter resets and percentage reporting stabilises.

Energy 4G not powering on after the replacement cell sat in storage

Li-polymer cells self-discharge in storage. If the AHB474067P cell dropped below approximately 2.5V per cell before installation, the BMS enters lockout to prevent damage and the phone will show no response at all. Connect the handset to a wall charger — not a USB port — and leave it for 20–30 minutes without pressing the power button. The charge IC on the phone will trickle current into the cell to lift it above the BMS recovery threshold, typically around 2.9V, at which point normal charging resumes.