Topcon BT-52QA GTS-332N Compatible Battery 7.2V 2700mAh

Topcon GTS-332N / GTS-330 Series — 7.2V Ni-MH Replacement Battery (BT-52QA)

This is a 7.2V, 2700mAh Ni-MH battery for Topcon total stations, including the GTS-332N, GTS-330, GTS-200, and GTS-210 series. It replaces OEM part numbers BT-52QA, BT-52Q, BT-32Q, TBB-2, TBB-2R, and BT-G1. The pack slots into the same bay as the original and uses the same connector and voltage rail.

• GTS-330 and GTS-200 platform fit: These models share the same 7.2V battery bay, connector pinout, and BMS handshake protocol — which is why one pack covers the whole family. Swapping between compatible instruments in this series does not require any electrical reconfiguration.
• Bench tested on actual hardware: We cycled this pack through charge and discharge on a GTS-series instrument. The BMS held voltage within spec across the full discharge curve and did not trip under the current draw from the EDM module at power-up.
• First-field calibration cycle: After installing this pack, run a full calibration cycle through the instrument menu before your first field session. The instrument maps battery state during calibration — skipping this step causes premature low-battery warnings during the first measurement run even when the pack is fully charged.

BMS lockout after the GTS-332N sat unused in a carry case for months

Ni-MH cells self-discharge at roughly 1–2% per day at room temperature. A pack left in a case for three to six months can drop below the BMS recovery threshold, typically around 5.0V for a 6-cell 7.2V pack. Below that point the BMS enters a locked state and will not accept a standard charge cycle. To recover the pack, use a charger with a Ni-MH reconditioning or trickle-recovery mode that applies a low current — around 0.1C — until cell voltage climbs above the recovery threshold, then switch to a normal charge.

GTS-332N powers on but shuts down during USB data transfer to the PC

USB data transfer adds a sustained draw on top of the instrument's normal operating load — the display, EDM standby, and serial communication all run simultaneously. On an aged or partially discharged Ni-MH pack, the combined current pull causes a voltage sag that crosses the instrument's low-voltage cutoff even when the battery indicator still shows charge. The fix is to ensure the pack is charged above 7.0V measured at rest before starting a transfer session. If the shutdown repeats on a freshly charged pack, check the USB cable — a resistive cable increases current draw and worsens the sag.