Jilong 500E Survey Instrument Compatible Battery 10.8V 3400mAh

Jilong 500E — 10.8V Li-ion Replacement Battery (BTR-34S)

This is a 10.8V, 3400mAh Li-ion battery for the Jilong 500E surveying instrument. It replaces OEM part BTR-34S and restores full power to the unit for field measurement and data collection sessions. Capacity figures are taken from the product specification — 36.72Wh total energy.

• Jilong 500E platform fit: The 500E uses a fixed voltage rail matched to the BTR-34S pack form factor. The connector pinout and BMS communication protocol are specific to this instrument family — swapping in a generic pack at a different voltage or with mismatched BMS signalling will trigger a battery error or prevent startup entirely.
• Bench tested on actual hardware: We cycled this pack through the 500E's power-on sequence and sensor initialisation phase, where current draw spikes briefly as the instrument activates its measurement modules. The BMS held without tripping on that initial surge, and voltage under sustained sensor load stayed within the instrument's operating window.
• Post-install calibration on the 500E: After fitting this pack, run a full calibration cycle through the instrument menu before your first field session. The 500E maps battery state during calibration — skipping this step causes the instrument to display premature low-battery warnings even when the pack is fully charged.

BMS cutoff when the 500E initialises its measurement modules

When the 500E powers on, the measurement modules draw a short current spike as they initialise — this is normal behaviour, but an aged or partially discharged pack can hit the BMS overcurrent threshold at exactly this moment. The BMS interprets the spike as a fault and cuts output before the instrument fully boots. This replacement pack is rated to handle that initialisation surge without tripping. If cutoff still occurs, charge the pack to full before the next power-on attempt — a cell below roughly 3.5V per cell under load is the usual trigger.

Readings resetting or dropping out mid-logging session

A sustained sensor load during active logging draws more current than standby, and a degraded pack will show voltage sag that dips below the 500E's minimum operating threshold — the instrument interprets this as a low-voltage event and resets the active session. This is different from a full shutdown: the display may recover quickly, but logged data for that interval is lost. The fix is a pack with cells that hold voltage under continuous load, not just at rest. After fitting this battery, confirm the resting voltage reads above 11.5V on the instrument's battery indicator before starting a long logging run.