Marantz RC5200 Replacement Battery 4.8V 700mAh Ni-MH

Marantz RC5200 / RC9500 Series — 4.8V Ni-MH Replacement Battery (8100 911 02101)

This is a 4.8V, 700mAh Ni-MH rechargeable battery for Marantz remote controls, replacing OEM part 8100 911 02101. It fits the RC5200, RC5400, RC9200, and RC9500 among other models in the same remote family. Capacity figure is from the product specification — 3.36Wh total energy storage.

• RC5200 / RC9500 remote family: These remotes share the same battery bay dimensions, 4.8V nominal voltage rail, and connector footprint. One replacement SKU covers the full group because the BMS handshake and charge termination behaviour are identical across them.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a Marantz-compatible remote chassis. The battery reached full charge termination cleanly at the expected delta-V drop, and the BMS did not flag any cell mismatch or overvoltage condition.
• Ni-MH charge cycle care for rechargeable remotes: Ni-MH cells in low-draw devices like remotes suffer from shallow-cycle degradation. Avoid leaving the remote on the dock continuously at 100% — let it discharge to around 30–40% capacity before placing it back on the charger to maintain cell health over time.

Why the RC5200 IR signal weakens before the battery reads as flat

Ni-MH cells hold a relatively flat voltage curve through most of their discharge, then drop sharply near the end. The RC5200's IR LED requires a minimum voltage to fire at full intensity. Once cell voltage sags below that threshold — even if the battery isn't fully depleted — the IR pulse weakens and range drops noticeably. The remote may still light up or register a button press internally, but the signal won't reach the receiver reliably. Replacing the battery restores full LED drive voltage and normal operating range.

Remote completely unresponsive after fitting the new battery

The most common cause is reversed polarity on installation. The RC5200 battery bay connector is keyed, but the cell can physically seat incorrectly if forced. Remove the battery and confirm the positive terminal aligns with the positive marking in the bay. If orientation is correct and the remote still won't respond, hold any button for 10 seconds after install — some Marantz remotes require a brief wake cycle before the microcontroller initialises off a fresh cell. Check that the battery is reading at least 4.5V under light load before ruling out the cell itself.