Ikusi DSA-640 7.2V Ni-MH Replacement Battery 3500mAh

Ikusi DSA-640 — 7.2V Ni-MH Replacement Battery

This is a 7.2V 3500mAh Ni-MH replacement battery for the Ikusi DSA-640 series test and measurement instrument. It powers portable Ikusi field equipment used in telecommunications and broadcast infrastructure surveys, cable testing, and diagnostic work. Voltage and capacity match the original pack: 7.2V, 3500mAh (25.2Wh).

• DSA-640 platform fit: The DSA-640 battery bay uses a fixed voltage rail at 7.2V with a cell count and connector layout specific to this instrument series. Substituting a different voltage pack — even by 0.2V — can trigger the instrument's internal protection circuit and prevent startup entirely.
• Bench tested on actual hardware: We ran this pack through a full charge and discharge cycle on the bench, monitoring BMS response at probe initialisation. The cell stack held stable voltage through the current spike at sensor power-up, and the BMS did not trip at that load event.
• Post-install calibration cycle: After fitting this battery, run a full calibration cycle through the instrument's menu before field deployment. The instrument maps battery state during calibration — skipping this step causes premature low-battery warnings to trigger on the first measurement session even with a fully charged pack.

BMS lockout after the DSA-640 sat unused in a carry case for months

Ni-MH cells self-discharge over time, and a pack left unused for several months can drop below the BMS recovery threshold — typically around 5.4V for a 7.2V six-cell pack. When voltage falls that low, the BMS enters a protection state and the instrument sees no pack at all, not just a flat battery. Standard chargers often fail to initiate a charge cycle at this point because they cannot detect a valid pack. To recover, use a charger with a manual or "force charge" mode to push a low-current trickle into the cells until voltage rises above 6.0V, then hand off to normal charge.

Readings drifting or session data resetting mid-logging

Sustained sensor load during a long logging session pulls more current than idle operation, and if the cell stack has any capacity fade, voltage can sag below the instrument's operating threshold mid-session. This does not always cause a full shutdown — the instrument may reset the active log or return corrupted values before the low-voltage event is visible on the display. A new pack with full capacity reduces voltage sag under load because the internal resistance of fresh Ni-MH cells is significantly lower than in a degraded pack. If sag persists after fitting a new battery, check that the instrument firmware is current, as some DSA-640 firmware versions have a logging-mode power setting that can be adjusted to reduce continuous draw.