MOLI MCC1821 Compatible Battery 7.4V 2000mAh Li-ion

MOLI MCC1821 / MCR-1821 Series — 7.4V Li-ion Replacement Battery

This is a 7.4V 2000mAh (14.8Wh) Li-ion replacement battery for the MOLI MCC1821, MCR-1821, MCR-1821C, and MCR-1821C/1 series field instruments. These are portable survey and measurement devices used in data collection, site diagnostics, and extended field work. When the original pack degrades, this unit restores full operating voltage to the instrument's internal measurement circuits.

• MCC1821 and MCR-1821 family fit: These models share the same 7.4V battery bay, connector pinout, and BMS communication protocol — that's why one pack covers the full MCR-1821 line including the C and C/1 variants. Voltage rail and physical form factor are identical across the group.
• Bench tested on actual hardware: We ran this pack through a full charge-discharge cycle on the MCR-1821 platform and logged BMS handshake confirmation at startup. The protection circuit responded correctly to both probe-initialisation current spikes and sustained sensor load without tripping.
• Calibration cycle before first field deployment: After installing this battery, run a full calibration cycle through the instrument menu before taking it into the field. The instrument maps battery state during calibration — skipping this step causes premature low-battery warnings during your first measurement session, even when the pack is fully charged.

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

Li-ion cells self-discharge slowly during storage. If the pack drops below approximately 2.5V per cell (5.0V total), the BMS enters a deep-discharge lockout state and will not respond to a standard charge cycle. The charger sees the pack as absent or faulty. To recover it, apply a slow preconditioning charge — many smart chargers have a "wake" or "recovery" mode that trickles current in at 0.1C until cell voltage climbs back above the BMS recovery threshold, typically around 5.8–6.0V for a 7.4V pack. Once above that threshold, the BMS re-initialises and normal charging resumes.

Instrument shuts down mid-measurement despite the battery indicator showing charge remaining

This happens when the battery's internal resistance has risen enough that sustained sensor load causes a voltage dropout below the instrument's cutoff threshold — even though the resting voltage looked acceptable. The instrument reads voltage at rest, shows a healthy percentage, but collapses under load when the probe draws continuous current. With a fresh pack, internal resistance is low and the voltage holds steady under that same load. If shutdowns stop after fitting this replacement, the original cell's capacity had faded well below its rated 2000mAh — the indicator was reading resting voltage, not true state of charge.