About this replacement
Uniden TRU-C46 / TRU-C56 — 3.7V Li-ion Replacement Battery (BT-925)
This is a 3.7V Li-ion battery rated at 750mAh (2.78Wh), built to replace the OEM BT-925 pack in Uniden TRU-C46 and TRU-C56 cordless phone handsets. It fits the battery bay directly and connects via the same terminal layout as the original. Voltage and capacity match what the handset's charging circuit expects.
- TRU-C46 and TRU-C56 compatibility: Both handsets run on the same 3.7V single-cell Li-ion platform and share the BT-925 form factor, connector pinout, and BMS handshake requirements. One replacement covers either model.
- Bench tested on actual hardware: We ran this cell through charge acceptance and load discharge on the TRU-C46 handset. The BMS accepted the base station charge signal without fault, and voltage held stable across both talk and standby draw cycles.
- First charge on Li-ion cordless handsets: After installing this battery, seat the handset in the base and leave it for a full uninterrupted charge before first use. Li-ion cells that ship in storage-state can trigger a shallow charge termination if pulled early — the base needs time to bring the cell up from its resting voltage to full capacity.
Why the TRU-C46 loses range after a battery swap
DECT handsets draw a spike of current each time they transmit to the base station. If the replacement battery's internal resistance is higher than expected — or if the cell hasn't completed its first full charge cycle — voltage sags under that RF transmit load. The handset's RF output drops to compensate, which shortens the usable range between handset and base. Running two or three full charge-discharge cycles brings the cell's internal resistance down and stabilises transmit voltage.
Handset not pairing with base after battery replacement
Removing the battery on some Uniden DECT handsets wipes the pairing registration stored in the handset's volatile memory. When the new battery is installed, the handset powers up without a stored base ID and shows no line or signal. To fix this, re-register the handset from the base station menu — on the TRU-C46, hold the FIND HANDSET button on the base for five seconds while the handset is powered on to re-initiate pairing.