MOLI MCC1821 Replacement Battery 7.4V 2600mAh Li-ion

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

This is a 7.4V 2600mAh (19.24Wh) lithium-ion battery for the MOLI MCC1821, MCR-1821, MCR-1821C, and MCR-1821C/1 portable two-way radios. These units are used in surveying, field operations, and equipment coordination where a dead battery mid-session is not an option. Voltage and cell format match the original pack exactly.

• MCC1821 and MCR-1821 series compatibility: All listed models share the same 7.4V nominal rail, connector pinout, and BMS handshake protocol. Swapping between MCC and MCR variants does not require any configuration change — the pack negotiates with the radio's charge controller the same way the factory unit does.
• Bench tested on actual hardware: We cycled this pack through full charge and discharge on the MCC1821 platform, monitoring BMS cutoff thresholds at both the low-voltage floor and the high-voltage ceiling. The protection circuit responded correctly at both endpoints without triggering false over-current trips during normal radio TX bursts.
• Field deployment prep for surveying operations: After installing this pack, run the radio through at least one full transmit-receive session before heading into the field. The radio's fuel gauge recalibrates its percentage display against the new cell's voltage curve during active use — skipping this step can cause the indicator to show premature low-battery warnings on the first deployment.

Why the MCR-1821 drops off-air mid-transmission after a battery swap

During a TX keying event, the radio draws a short current spike above idle draw. If the BMS on a new or partially charged pack has not yet settled its internal voltage reference, that spike can read as an over-current condition and trigger a momentary protection cutoff. This is not a faulty pack — it is the BMS being conservative with an unconditioned cell. Running two or three full transmit-receive cycles after installation lets the BMS establish a stable baseline. After that, mid-transmission dropouts from the battery side stop entirely.

Battery percentage jumping erratically on the display after fitting a new pack

The MCC1821 and MCR-1821 series use a voltage-threshold method to estimate charge level. A new cell's resting voltage profile differs slightly from a used original pack, so the indicator can swing between readings — especially in the upper 80–100% range — until the radio maps the new curve. This is a display calibration issue, not a capacity problem. Charge the new pack to full, then run it down to the point where the radio gives a low-battery alert, then recharge fully. After one complete cycle, the percentage display stabilises to within a few percent of actual state of charge.