About this replacement
Texas Instruments TI-Navigator — 3.7V Li-ion Replacement Battery (3.6L43BPA)
This is a 3.7V Li-ion battery rated at 6800mAh (25.16Wh), built to the same electrical spec as OEM part 3.6L43BPA. It fits the Texas Instruments TI-Navigator handheld unit used in classroom wireless network systems. The battery slots into the same housing and connects through the same BMS handshake as the original pack.
- TI-Navigator handheld compatibility: The TI-Navigator system runs student handhelds on a single-cell 3.7V Li-ion rail with a specific BMS communication protocol. This pack matches that voltage rail and the connector geometry of the OEM 3.6L43BPA, so the base station recognises it without firmware complaints.
- Bench tested on actual hardware: We cycled this pack through the TI-Navigator's charge and discharge sequence. The BMS passed charge termination correctly at full capacity, and the unit reported battery status without errors across multiple full cycles.
- First-use cycle on classroom handhelds: After installing, let the handheld discharge through at least one full classroom session before recharging — the TI-Navigator's charge indicator recalibrates its threshold map on the first real-load cycle, and charging immediately from near-full on a new cell skews the percentage display for weeks.
TI-Navigator pack refusing to charge after sitting unused in storage
Li-ion cells that sit uncharged for several months can drop below the BMS recovery threshold — typically around 2.5V per cell. When voltage falls that low, the BMS enters a sleep state and blocks normal charging as a safety measure. The TI-Navigator charger will show no activity or a fault indicator when this happens. Connecting the handheld to a USB power source for 15–20 minutes at low current can nudge the cell above the recovery threshold and allow the BMS to re-engage normal charging.
Handheld shuts off mid-session during wireless polling
The TI-Navigator radio module draws a short burst of current each time it transmits a response to the hub — this spike can trip the BMS overcurrent cutoff if the cell voltage is already sitting at the lower edge of its discharge curve. The unit powers off instantly with no warning, and the session data for that student is lost. This is not a faulty battery; it is the BMS protecting the cell at low state of charge. Recharge the handheld before the indicator drops below 20% — at that point cell voltage under transmit load can fall below the 3.0V cutoff threshold.