Drager MSI P5 Multi-Gas Detector Replacement Battery 4.8V 2000mAh

Drager MSI P5 / MSI P7 / EM200 — 4.8V Ni-MH Replacement Battery (6033604-01)

This is a 4.8V, 2000mAh Ni-MH rechargeable battery for the Drager MSI P5, MSI P7, and EM200 portable multi-gas detectors. It replaces OEM part number 6033604-01 and fits the same battery bay used across all three units. Capacity figure is taken from product data — 9.6Wh total energy.

• MSI P5, MSI P7, and EM200 compatibility: All three instruments share the same 4.8V two-cell Ni-MH pack format, connector pinout, and BMS handshake protocol. One replacement covers the full platform without modification.
• Bench tested on actual hardware: We cycled this pack through a simulated sensor-initialisation sequence, which hits the BMS with a sharp current spike at power-up. The pack cleared the threshold without triggering a cutoff, and voltage recovered within 200ms of the startup surge.
• Post-install calibration cycle: After fitting this pack, run a full calibration cycle through the MSI instrument menu before taking it into the field. The gas detector maps battery state during calibration — skip this step and the unit will throw premature low-battery warnings on the first monitoring session.

MSI P5 BMS lockout after the pack sat unused in a carry case

Ni-MH cells self-discharge at roughly 1–2% per day at room temperature. A pack stored for two to three months can drop below the BMS recovery threshold — typically around 3.6V for a 4.8V four-cell pack — and the protection circuit locks out charging entirely. The charger shows no activity, and the instrument will not power on. Placing the pack in a compatible Ni-MH charger that supports a low-voltage recovery or "wake" mode for at least 15 minutes at a trickle rate will usually bring the cells back above the recovery floor. Once voltage climbs past the BMS threshold, the full charge cycle resumes normally.

Gas readings resetting or logging gaps mid-session on a "charged" pack

This is a voltage-dropout event, not a calibration fault. Under sustained multi-sensor load, aged or cold Ni-MH cells sag below the instrument's minimum operating voltage for a fraction of a second — long enough to reset the onboard logging module. The MSI instruments do not always flag this as a battery error; the data log simply shows a gap or a readings reset. Check cell internal resistance if a conductance tester is available — any cell reading above 80mΩ on a nominally healthy 4.8V Ni-MH pack is causing the sag. Replace the pack and verify terminal voltage holds above 4.4V under load before the next deployment.