About this replacement
Sieval SV-118 — 3.7V Li-ion Replacement Battery (SV10)
This is a 3.7V, 1900mAh Li-ion replacement battery for the Sieval SV-118 portable surveying and testing instrument. It uses OEM part number SV10 and fits the SV-118 directly. Voltage and cell geometry match the original pack: 63.78 × 40.94 × 6.03mm.
- SV-118 platform fit: The SV-118 draws power through a single-cell 3.7V rail. This pack matches that rail, the connector pinout, and the BMS communication expected by the instrument's power management circuit. No adapters needed.
- Bench tested on actual hardware: We ran the pack through probe initialisation cycles and sustained sensor load sequences. The BMS held voltage through the current spike at probe power-up and did not trip during extended logging draws.
- First-use calibration step: After installing, run a full calibration cycle through the instrument menu before field deployment. The SV-118 maps battery state during calibration — skipping this step causes premature low-battery warnings during the first measurement session.
BMS cutoff when the SV-118 probe module initialises
At probe power-up, the SV-118 pulls a short current spike as the sensor module initialises. An aged or deeply discharged original pack can't sustain that spike, so the BMS trips and the instrument cuts out immediately. This replacement pack's BMS is rated for that initialisation surge without tripping. If the instrument still cuts at probe power-up after installation, charge the pack fully first — the BMS requires the cell above 3.6V before it will hold through the spike.
Display percentage jumping or resetting on reboot after pack swap
The SV-118 tracks battery percentage against a learned voltage curve from the old cell. After installing a new pack, the instrument's indicator often reads incorrectly for the first few charge-discharge cycles. This is a voltage-threshold recalibration issue, not a fault with the new battery. Run two full charge and discharge cycles through normal instrument operation and the display will stabilise to accurate readings.