JDSU Test-Um NT905 Replacement Battery 7.4V 2200mAh

JDSU Test-Um NT905 Validator — 7.4V Li-ion Replacement Battery (NT93)

This 7.4V 2200mAh Li-ion pack replaces the OEM NT93 battery in the Test-Um NT905 Validator and the NT99, NT1150, and NT1155 series. It powers the instrument's active line-testing and connectivity validation circuits. Rated at 16.28Wh, it matches the original voltage and capacity spec exactly.

• NT905 / NT99 / NT1150 / NT1155 platform fit: These models share the same 7.4V two-cell Li-ion rail, identical connector footprint, and a BMS handshake that authenticates pack voltage on startup — all four units pull from the same battery architecture.
• Bench tested on actual hardware: We cycled this pack through full charge and discharge on a field-equivalent load. The BMS held stable across the NT905's active measurement draw, with no mid-test cutoff events during probe initialisation.
• Post-install calibration on the NT905: After fitting this pack, run the instrument through a full power-on calibration cycle before field deployment. The NT905 maps battery state during that sequence — skip it and the low-battery indicator will trigger early on your first real testing session.

NT905 BMS lockout after the unit sat unused in a carry case for months

Li-ion cells self-discharge over time. If the NT905 sat unused long enough, the pack voltage drops below the BMS recovery threshold — typically around 2.5V per cell — and the protection circuit locks the pack in a sleep state. At that point the instrument won't power on and won't register on a charger. Most NT93-format packs recover with a low-current pre-charge pulse held for 10–20 minutes before normal charging resumes. If the original OEM pack won't recover, that's the failure mode — a replacement pack resolves it immediately.

NT905 shuts down mid-measurement with no low-battery warning

This happens when the pack's cells have degraded enough that voltage sags sharply under the sustained draw of active line testing — even if the indicator showed a healthy charge before the session started. The NT905's power circuit has a hard undervoltage cutoff; when cell voltage dips below that threshold under load, the unit shuts off instantly with no warning. A fresh pack with full cell capacity holds voltage flat under that load. After fitting the replacement, run the post-install calibration cycle so the instrument recalibrates its voltage-to-percentage mapping to the new cells — this prevents the same symptom reappearing at incorrect state-of-charge readings.