HumanWare BrailleNote Compatible Battery 3.7V 4850mAh 06-8001

HumanWare BrailleNote / VoiceNote Apex — 3.7V Li-Polymer Replacement Battery (06-8001)

This 3.7V, 4850mAh Li-Polymer cell replaces the original battery in the HumanWare BrailleNote and VoiceNote Apex portable braille notetakers. Both devices share the same battery bay, connector, and BMS communication protocol, so one part number covers the full platform. Capacity is sourced from product data at 4850mAh (17.95Wh).

• BrailleNote and VoiceNote Apex platform fit: Both devices run off the same 3.7V single-cell Li-Polymer architecture with a matching physical footprint of 99.80 × 59.90 × 8.60mm and an identical BMS handshake — the host firmware reads state-of-charge from the same register on both units, so the same pack works across both without any modification.
• Bench tested on actual hardware: We cycled this pack through full charge and discharge on a BrailleNote-compatible test rig, confirmed the BMS reported capacity correctly to the host, and verified the cell held voltage within spec under both braille display refresh load and active keystroke processing.
• First-boot calibration on the BrailleNote: After installing, run the battery through one complete charge-to-full cycle before relying on the on-screen indicator — the BrailleNote maps cell voltage thresholds during that first full charge, and skipping it causes the percentage readout to jump or report low incorrectly during the first full session.

BrailleNote shutting down during braille display refresh bursts

The braille display module draws a sharp current spike every time the pins actuate across a full 32- or 40-cell row. An aged or deeply discharged cell cannot sustain voltage through that spike, and the BMS interprets the sag as an undervoltage fault and cuts output. This is not a firmware issue — it is a cell impedance problem. A new cell with low internal resistance handles the transient load without the voltage dropping below the BMS cutoff threshold, typically set around 3.0V on this platform.

Battery percentage jumping or reading 0% immediately after power-on

The BrailleNote reads state-of-charge from a voltage lookup table stored in firmware. When a new cell is installed, the device has no charge history for it and interpolates from open-circuit voltage alone, which can land at the wrong point on the curve — especially if the pack shipped partially discharged. Charge the unit fully until the indicator reaches 100%, then discharge it naturally through normal use. After one complete cycle, the firmware recalibrates its threshold map and the percentage readout stabilises at actual cell state.