About this replacement
Symtech CVA-3EZ / HBA-5 Series — 9.6V Ni-MH Replacement Battery (SY05011500)
This is a 9.6V 1800mAh Ni-MH battery for the Symtech CVA-3EZ total station and HBA-5 / HBA-5P surveying instruments. It replaces OEM part numbers SY05011500 and SYM05011500. Capacity is rated at 1800mAh (17.28Wh) — matching the original specification.
- CVA-3EZ, HBA-5, and HBA-5P fit: These three models share the same 9.6V Ni-MH power rail, connector pinout, and BMS communication protocol — one battery pack covers all three without any modification.
- Bench tested on actual hardware: We cycled this pack through cold-start initialisation on the CVA-3EZ. The BMS held stable during sensor power-up surges and sustained measurement logging without triggering a protective cutoff.
- First-field calibration cycle: After installing a new pack, run a full calibration cycle through the instrument menu before heading into the field. The CVA-3EZ maps battery state during calibration — skip this step and the instrument will throw premature low-battery warnings on the first measurement session, even with a fully charged cell.
CVA-3EZ shutting down mid-measurement with a charged battery
The CVA-3EZ draws a short high-current spike each time the angle encoder or EDM module initialises a reading cycle. On a degraded or deeply discharged Ni-MH cell, this spike causes voltage to sag below the BMS protection threshold — triggering an immediate shutdown. A new cell at full charge holds enough internal headroom to absorb that spike without dropping out. If shutdowns happen only at the start of a measurement sequence, the spike — not total capacity — is the cause.
New pack not recognised by the instrument after sitting unused in carry case
Ni-MH packs self-discharge during storage. If the pack voltage drops below roughly 8.0V before first use, the instrument's power circuit may not detect a valid battery — it sees a voltage level consistent with a dead or absent cell. The fix is to place the pack on the OEM charger and allow a full charge cycle to complete before inserting it into the instrument. Once the BMS recovers to nominal voltage, the CVA-3EZ will recognise the pack on the next power-on.