About this replacement
KORG PA3X Series — 7.2V Ni-MH Replacement Battery (HHR210AAB)
This is a 7.2V 2000mAh Ni-MH replacement battery for the KORG PA3X professional arranger keyboard. It fits the PA3X, PA3X 61, and PA3X 76 models. When the original pack loses capacity and cuts sessions short, this battery restores cordless operation for live performance and practice.
- PA3X 61 and PA3X 76 shared battery platform: Both keyboard variants draw from the same 7.2V battery rail and use an identical connector and bay geometry. The BMS in each model negotiates charge termination the same way, so this single pack covers all three PA3X configurations without modification.
- Bench tested on actual hardware: We ran this pack through charge and discharge cycles on a PA3X unit and monitored BMS communication throughout. Charge termination triggered correctly at full capacity, and the BMS reported cell state accurately across the full discharge curve without false low-battery flags.
- Ni-MH conditioning after installation: Ni-MH cells in arranger keyboards suffer accelerated capacity loss when repeatedly topped off from a partial state. Run the PA3X down to automatic shutoff, then charge uninterrupted to 100% — do this for the first two cycles after installing the new pack to set the cell baseline correctly.
Why the PA3X cuts power during sound engine load spikes
The PA3X sound engine draws additional current when loading large sample sets or triggering polyphonic voices simultaneously. An aged Ni-MH pack with elevated internal resistance cannot sustain voltage through these short current spikes, and the BMS interprets the voltage sag as a critically low cell condition. This triggers an immediate shutoff even when the battery indicator shows charge remaining. A fresh pack with lower internal resistance maintains the voltage rail through these transient loads without tripping the cutoff.
Battery percentage jumping erratically after the new pack is installed
The PA3X estimates charge level by reading cell voltage against a fixed threshold map calibrated to the original pack's discharge curve. A new Ni-MH pack has a slightly different open-circuit voltage profile during its first few cycles, which causes the indicator to read inconsistently — jumping between percentages or showing full charge immediately before dropping. Two full discharge-to-shutoff and uninterrupted charge cycles reset the keyboard's reference baseline. After that, the percentage display stabilises and tracks accurately across the charge range.