AeroFlex IFR AG205012 Replacement Battery 7.4V 10400mAh

AeroFlex IFR / Marconi — 7.4V Li-ion Replacement Battery (AG205012)

This 7.4V 10400mAh (76.96Wh) Li-ion pack replaces the AG205012 battery in AeroFlex IFR and Marconi series test and measurement instruments. These are field-deployed diagnostic devices used in survey, inspection, and signal testing work. The pack fits the same connector and voltage rail as the original.

• IFR and Marconi platform fit: Both instrument families run the same 7.4V bus and use the AG205012 form factor. The BMS handshake, connector pinout, and cell configuration are shared across this platform, so one pack covers both lines.
• Bench tested on actual hardware: We cycled this pack under sustained sensor load and through probe initialisation events. The BMS held stable through the inrush current spike at probe power-up and did not trip cutoff during extended logging sequences.
• Post-install calibration cycle: After fitting this pack, run a full calibration cycle through the instrument menu before field deployment. The instrument maps battery state during that sequence. Skipping it causes the low-battery warning to fire too early on the first measurement session, which reads as a fault rather than a setup step.

BMS cutoff when a probe or sensor module initialises

When the IFR powers up a connected probe, the sensor module draws a short inrush current that can exceed the BMS overcurrent threshold on a degraded or deeply discharged pack. The BMS interprets this spike as a fault and cuts the output rail, which shuts the instrument down immediately at startup. This pack's BMS is rated to handle that initialisation spike without tripping. If the issue persists after fitting a new pack, check that the probe connector is fully seated — a poor contact increases resistance and amplifies the apparent current draw.

Instrument displays an inconsistent battery percentage after each reboot

When a new cell pack replaces one that was heavily degraded, the instrument's voltage-threshold indicator has no reference point for the new cell's discharge curve. It reads the open-circuit voltage and maps it against old thresholds, which produces a percentage that jumps or resets differently on each power cycle. Running two to three full discharge-and-charge cycles through the instrument normalises the threshold mapping. After that, the percentage readout stabilises — the indicator recalibrates to the new cell's actual voltage floor, typically around 6.0V at cutoff.