About this replacement
GRE Electric CSPAN — 3.7V Li-ion Replacement Battery (P1128PJ1BU)
This is a 3.7V, 2600mAh Li-ion replacement battery for the GRE Electric CSPAN cordless vacuum cleaner. It slots in where the original P1128PJ1BU cell sits, restoring power to the motor and suction system. Fits the CSPAN model only — confirm your model before ordering.
- CSPAN platform fit: The CSPAN runs a single-cell 3.7V Li-ion architecture. The motor controller draws directly from this cell, so voltage, physical dimensions (71.00 × 21.60 × 18.60mm), and BMS communication all need to match the original P1128PJ1BU spec exactly — which this cell does.
- Bench tested on actual hardware: We cycled this cell through full discharge-to-charge sequences under a simulated motor load. The BMS handled cutoff cleanly at the low-voltage threshold and accepted a full charge without triggering protection flags.
- Dock charging habit on the CSPAN: Do not leave the CSPAN sitting on its charging dock permanently. Continuous trickle charge on a single Li-ion cell accelerates capacity fade faster than on multi-cell packs. Charge to full, then remove it from the dock.
Suction dropping before the battery indicator hits low
This happens when the motor draws more current than the cell can sustain cleanly — voltage sags under load even though the resting voltage looks fine. A partially blocked filter is the most common trigger: restricted airflow forces the motor to work harder, pulling more amps than the BMS expects. The BMS doesn't trip completely, but the motor slows and suction drops noticeably. Clean or replace the filter first, then check whether the symptom persists on a freshly charged cell.
Motor cuts out mid-clean then recovers on its own
This is a BMS overcurrent trip, not a dead battery. When suction is restricted — blocked filter, hair wrap on the brush roll, or a sealed nozzle — the motor draws a sustained current spike that crosses the BMS cutoff threshold. The BMS shuts the output to protect the cell, then resets after a few seconds once current demand drops. Clear the restriction, wait for the BMS to recover, then restart. If it trips repeatedly on an unblocked machine, the cell itself may no longer hold enough capacity to meet motor-start current demand and needs replacing.