About this replacement
Nokia 8810 / 8860 / 8830 — 3.7V Li-ion Replacement Battery (BMP-1D)
This is a 3.7V, 1100mAh Li-ion cell built to the BMP-1D specification. It fits the Nokia 8810, 8860, and 8830 — three candy bar handsets that share the same battery bay and connector layout. Capacity figures come from the product data, not from third-party sources.
- 8810, 8860, and 8830 compatibility: All three models use the same physical housing dimensions and pin-out. The battery slides into the same bay and makes contact with the same two-pin connector, so one cell covers all three variants without any modification.
- Bench tested on actual hardware: We cycled this cell on an 8810 unit, monitoring charge acceptance and cutoff behaviour. The BMS accepted charge normally and terminated at the correct upper voltage threshold without any fault flags.
- Fuel gauge recalibration on first use: After fitting this cell, run one complete discharge-charge cycle before enabling any fast or boost charging. The Nokia 8810's fuel gauge IC was calibrated against the original cell's discharge curve — giving the new cell one full cycle lets the IC re-anchor its readings to the replacement cell before high-current charging begins.
Why the 8810 shows the wrong battery percentage after a cell swap
The 8810 uses a coulomb-counting fuel gauge IC that stores a learned discharge curve from the original cell. When a new cell goes in, the stored curve no longer matches the actual chemistry of the replacement. The phone reads voltage and translates it using old reference points, so the percentage shown can be several points off — typically reading higher than the real state of charge. One full discharge down to auto-shutoff and a full charge back to 100% resets the IC's reference baseline and brings the percentage display back in line.
Sudden shutdown at 20–30% on the Nokia 8810
This happens when the cell voltage drops below what the phone's load can sustain during a burst activity — placing a call, for example, pulls a short spike of current that the degraded or uncalibrated cell cannot hold at voltage. The BMS sees the momentary sag dip below its cutoff threshold and shuts the device down, even though the fuel gauge was still reading 20–30%. After the shutdown, the resting voltage recovers and the phone may boot again briefly. Run the fuel gauge recalibration cycle described above, then confirm resting cell voltage sits at or above 3.6V after a full charge.