HTC Flyer BG41200 Replacement Battery 3.7V 4000mAh

HTC Flyer / EVO View 4G — 3.7V Li-Polymer Replacement Battery (BG41200)

The BG41200 is a 3.7V, 4000mAh Li-Polymer battery for the HTC Flyer, P510E, and EVO View 4G tablets. This 7-inch Android tablet platform shares a single battery form factor across all three variants. Dimensions are 90.17 × 65.85 × 5.85mm — verify these against your existing cell before installing.

• Flyer, P510E, and EVO View 4G compatibility: All three models run the same voltage rail, use the same physical connector, and accept the same BMS handshake. One cell fits all variants without modification.
• Bench tested on actual hardware: We cycled this battery through charge and discharge on the Flyer platform. The BMS accepted the cell without fault codes, and the charge IC brought the pack to full voltage without thermal events.
• Fuel gauge reset after installation: After fitting this battery, run one full discharge to automatic shutoff, then charge uninterrupted to 100%. This gives the Flyer's fuel gauge IC a clean reference point against the new cell and eliminates the inaccurate percentage readings that appear immediately after a swap.

HTC Flyer shutting down at 15–25% remaining

The Flyer's SoC pulls harder when the display is on at full brightness alongside active WiFi — combined draw causes a voltage dip that the fuel gauge reads as empty before the cell actually is. The original battery's internal resistance increases with age, making this dip steeper and the cutoff earlier. A new cell with lower internal resistance flattens that sag and pushes the real cutoff lower. If shutdowns persist after fitting this battery, run one full calibration cycle and check that the reading stabilises above 3.6V under load before the device powers off.

HTC Flyer showing wrong battery percentage after replacement

The fuel gauge IC on the Flyer stores learned capacity data from the old cell. When you swap in a new battery, that stored data no longer matches the actual cell chemistry, so the percentage display drifts immediately. The fix is a single recalibration cycle: drain the tablet fully until it shuts itself off, then charge without interruption to 100%. After that cycle, the gauge re-anchors to the new cell's actual charge curve and percentage accuracy returns. If the reading still jumps after one cycle, run a second — some units need two passes to fully overwrite the stored model.