Juniper 2EXL7431-001 Allegro 2 Compatible Battery 3.7V 13600mAh

Juniper Allegro 2 / Archer 2 — 3.7V Li-ion Replacement Battery (2EXL7431-001)

This 3.7V Li-ion battery replaces OEM part 2EXL7431-001 in the Juniper Allegro 2 and Archer 2 portable data collection computers. Capacity is 13600mAh (50.32Wh). It fits the full AG2 and AR2 platform used in geospatial survey, environmental assessment, and field mapping work.

• Allegro 2 / Archer 2 platform fit: The Allegro 2 and Archer 2 share the same battery bay geometry, connector pinout, and BMS communication protocol — that is why one cell pack covers both lines. The Allegro 2 (AG2) and Archer 2 (AR2) variants also use the same voltage rail, so the BMS handshake clears on all of them without modification.
• Bench tested on actual hardware: We ran this pack through power-on sequencing, GPS lock, and sustained data-logging load on an Allegro 2 unit. The BMS held steady through probe initialisation spikes and did not trip on the combined USB-host and sensor draw that catches weaker cells off guard.
• First-use calibration on the Allegro 2: After installing, run a full calibration cycle through the Allegro 2 instrument menu before field deployment. The device maps battery state during that cycle — skipping it causes premature low-battery warnings during your first measurement session in the field, even when the pack is near full charge.

Why the Allegro 2 shuts down mid-session despite showing charge on screen

The Allegro 2 draws a sustained combined load during active GPS logging, radio sync, and backlit display — this can pull the cell voltage below the BMS cutoff threshold momentarily, even when the state-of-charge indicator still reads high. A worn or partially charged cell cannot hold the voltage rail steady under that load, so the BMS trips and the unit cuts out. A fresh, fully charged pack resolves this because the internal resistance is low enough to supply the peak current without voltage sag. If shutdowns continue after swapping the pack, check that the calibration cycle completed fully — an uncalibrated pack will show a falsely high percentage right up until the BMS trips.

Allegro 2 not recognising a new pack after the unit sat unused in a carry case

Li-ion cells self-discharge slowly in storage, and if the pack drops below roughly 2.5V per cell, the BMS enters a low-voltage lockout state and stops responding to the device. The Allegro 2 reads no battery or shows an error because the BMS is not communicating, not because the pack is faulty. Connect the pack to the OEM charger and leave it for at least 30–60 minutes before attempting to power the unit on — most chargers apply a recovery trickle charge below 2.8V per cell that wakes the BMS. Once the pack climbs above 3.0V per cell, normal charging and device recognition resume.