About this replacement
HTC One Mini / M4 — 3.8V Li-Polymer Replacement Battery (BL80100)
This is a 3.8V, 1800mAh Li-Polymer replacement battery for the HTC One Mini and M4 smartphones. It replaces OEM part numbers BL80100, BO58100, and 35H00210-00M. It also fits the One Mini LTE 601s and One Mini LTE NA variants.
- One Mini / M4 compatibility: These models share the same 3.8V cell voltage, physical dimensions, and connector pinout. The BMS handshake protocol is consistent across the 601s and LTE NA variants, so this cell seats and communicates correctly with the charge IC on all listed models.
- Bench tested on actual hardware: We ran this cell through a full charge cycle on the One Mini charge IC. The BMS accepted the initial charge current without tripping, balanced across the cell correctly, and terminated at 4.35V as expected for a Li-Polymer cell on this platform.
- Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This allows the fuel gauge IC to recalibrate its coulomb counter against the new cell's discharge curve before high-current charging pushes load into an uncalibrated cell.
Why the One Mini reports wrong battery percentage after a cell swap
The One Mini uses a coulomb-counting fuel gauge IC that builds its charge model against the original cell's capacity curve over time. When you swap in a new cell, that learned model is still mapped to the old cell's degraded curve. The percentage readout will be inaccurate — often reading higher than actual charge — until the IC rebuilds its model. One complete slow charge-discharge cycle forces the IC to re-anchor its endpoints and correct the percentage display.
Sudden shutdown at 20–30% remaining on the replacement cell
This happens when the modem or display draws a surge current that collapses cell voltage below the BMS cutoff threshold, even though the fuel gauge still shows charge remaining. On a new cell with an uncalibrated fuel gauge, the reported percentage and actual state of charge are misaligned — the phone shuts down at what looks like 25% but is actually near the voltage floor. Run one full discharge to below 10% without intervention, then charge uninterrupted to 100% to let the IC reset its low-voltage endpoint. After that cycle, shutdown should occur at or below 5% reported charge.