Nokia BH-607 Replacement Battery 3.7V 140mAh Li-Polymer

Nokia BH-607 / BH-900 / HS-36W — 3.7V Li-Polymer Replacement Battery

This is a 3.7V, 140mAh Li-Polymer cell for the Nokia BH-607, BH-900, and HS-36W Bluetooth headsets. It replaces the original cell when the headset stops holding charge or shuts off mid-call. Dimensions are 31.83 × 11.03 × 4.00mm — physical fit is exact for all three models.

• BH-607, BH-900, and HS-36W compatibility: All three headsets share the same compact Li-Polymer cell format, 3.7V rail, and connector pinout. The BMS in each model uses the same low-current cutoff threshold, so the cell swaps without any firmware mismatch.
• Bench tested on actual hardware: We cycled this cell under combined Bluetooth radio and audio draw. The BMS held the cutoff at the correct threshold and did not trip on the brief current spike when the radio re-pairs after a dropout.
• First-cycle base station charge: Place the headset in the base station for a complete charge cycle before making any calls. The base station firmware logs the new cell during this cycle and will not display an accurate charge indicator until it completes.

Voltage sag under combined audio and Bluetooth radio draw in the BH-607

The BH-607 runs audio decoding and the DECT/Bluetooth radio simultaneously. That combined draw in such a small housing creates brief current spikes that can push the cell voltage below the BMS cutoff threshold, especially on a degraded original cell. A fresh 140mAh cell at full charge sits at 4.2V and holds above 3.5V through normal call load. If the headset cuts mid-call, check that the cell was given a full first charge cycle — a cell delivered at storage voltage (around 3.7V) has not yet reached rated capacity.

Base station shows full charge but headset cuts off after a few minutes

This happens when the replacement cell is at storage voltage and the base station misreads state-of-charge on the first dock. The base registers the cell as full at roughly 3.7V without completing a true charge cycle. Run one full charge from near-empty to 4.2V in the base station before use. That cycle resets the base station's charge counter and the symptom does not return.