Grundig G6718 Replacement Battery 1.2V 1800mAh Ni-MH

Grundig G6718 / G5563 / G6536 / G6563 Series — 1.2V Ni-MH 1800mAh Replacement Battery

This is a 1.2V Ni-MH 1800mAh replacement battery for the Grundig G6718, G5563, G6536, G6563, and three additional compatible shaver models. It restores cordless operation when the original cell has degraded and the shaver either fails to hold a charge or cuts out under load. Dimensions are 49.90 × 14.30 × 14.30mm — a direct physical match for the original cell bay.

• G6718 / G5563 / G6536 / G6563 cell compatibility: These models share the same cylindrical cell format, voltage rail, and internal connector orientation. Swapping cells across this group works because the shaver PCB does not perform a BMS handshake — it reads voltage directly from the cell terminals.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on shaver-class motor loads. Voltage held above 1.1V through the working window and the shaver PCB registered a full charge state without fault flags.
• Charging port care after rinsing: If you rinse this shaver under water, wait until the charging port is completely dry before docking it. Moisture bridging the charging contacts causes a protection trip that the shaver reports as a dead battery rather than a charging error — the cell is fine, the contacts are not.

Capacity fade from daily partial charging on the G6718

Ni-MH cells in shavers are particularly vulnerable to shallow-cycle degradation. Docking the shaver every night before it depletes trains the cell to treat a partial state of charge as full capacity — the indicator drifts and usable runtime shrinks without any single obvious failure event. This happens faster in warm bathrooms where ambient heat accelerates cell memory formation. To reset the cycle, run the shaver to full cutoff twice before returning to regular dock charging.

Motor speed drops noticeably before the low-battery indicator activates

This is a voltage sag symptom, not an indicator fault. Under motor load, an aged Ni-MH cell drops below 1.0V before the shaver's voltage threshold triggers the low-battery warning — so the motor slows and foil pressure drops while the indicator still shows charge remaining. A fresh 1800mAh cell holds voltage more consistently under that same load. After fitting the new cell, run one full charge cycle to 1.45V before use to ensure the PCB recalibrates its cutoff reference correctly.