About this replacement
TDK Life On Record A33 — 7.2V Ni-MH Replacement Battery
This is a 7.2V, 2000mAh Ni-MH replacement battery for the TDK Life On Record A33 portable Bluetooth speaker. It fits directly into the A33 and restores full audio playback capability when the original cell no longer holds charge. Voltage and capacity match the factory specification exactly.
- Life On Record A33 fit: The A33 runs a single 7.2V Ni-MH pack to power both the amplifier board and Bluetooth radio simultaneously. Both subsystems draw from the same cell, so a degraded pack hits the voltage floor faster under combined load than it would powering either circuit alone.
- Bench tested on actual hardware: We cycled this pack through combined amplifier and Bluetooth radio draw. The cell voltage held above the A33's low-battery cutoff threshold across multiple discharge cycles, and the BMS did not trigger a premature shutdown under a mid-volume audio load.
- Ni-MH monthly discharge cycle: Unlike Li-ion, Ni-MH cells in the A33 benefit from a full discharge to near-empty once a month. Constant partial top-off charging without a full cycle causes voltage depression — a condition specific to Ni-MH chemistry that makes the cell appear weaker than it is and shortens usable pack life.
Audio distorting before the battery indicator reaches empty on the A33
The A33's amplifier pulls a sharp current spike at higher volumes. When the Ni-MH cell ages, its internal resistance rises and voltage sags under that spike even if the pack isn't fully discharged. The amplifier clips at that lower voltage, producing audible distortion before the battery LED signals low charge. Replacing the cell eliminates the high-resistance sag — a fresh 2000mAh Ni-MH pack should hold above 6.8V under peak amplifier draw.
A33 showing full charge indicator but audio cuts out after extended play
This is voltage depression from shallow cycling — the pack has been repeatedly topped off before dropping below 50%, which is a known Ni-MH failure mode. The cell's actual capacity shrinks, but the charge indicator doesn't reflect it because the surface charge looks full at rest. Run the new pack through two full discharge-and-recharge cycles after fitting it. This conditions the Ni-MH chemistry and aligns the fuel gauge with true remaining capacity.