AudioVox BTR1100 Compatible Battery 3.7V 1000mAh Li-ion

AudioVox CDM-1100 / CDM-130 — 3.7V Li-ion Replacement Battery (BTR1100)

This is a 3.7V, 1000mAh Li-ion replacement battery for the AudioVox CDM-1100 and CDM-130 candybar mobile phones. It uses OEM part number BTR1100 and slots directly into the original battery bay. Capacity is rated at 3.7Wh, matching the original cell specification.

• CDM-1100 and CDM-130 compatibility: Both handsets run the same 3.7V single-cell Li-ion rail and use the same battery bay dimensions, connector pinout, and BMS communication protocol — so one cell covers both models without modification.
• Bench tested on actual hardware: We cycled the cell through charge and discharge on CDM-series hardware. The BMS accepted the cell without triggering a fault, charge termination fired correctly at full voltage, and the protection circuit responded normally to low-voltage cutoff.
• Fuel gauge recalibration on first cycle: The CDM-1100 tracks capacity using a simple fuel gauge IC calibrated to the old cell's discharge curve. After installing this battery, run one full discharge down to automatic shutoff, then charge uninterrupted to 100% before normal use — this resets the reference curve to the new cell.

Why the CDM-1100 reports wrong battery percentage after a cell swap

The phone's fuel gauge IC builds its percentage estimate from a stored discharge curve tied to the original cell's impedance and capacity profile. A new cell has a different internal resistance, so the IC's model no longer matches reality. The result is percentage readings that jump or stall — typically skipping fast through the middle range. One complete discharge-to-shutoff and uninterrupted recharge retrains the IC to the new cell's actual curve.

Sudden shutdown at 20–30% on the replacement cell

This happens when the fuel gauge IC still holds the old cell's curve and believes voltage headroom remains — but the new cell's open-circuit voltage under voice-call load drops below the BMS protection threshold before the display reaches 0%. The BMS cuts power to protect the cell, which looks like a random hard shutdown. Run the recalibration cycle first: discharge to automatic shutoff, then recharge fully to 4.2V. If shutdowns continue after two full cycles, check that the battery contacts in the phone are clean and making full contact.