About this replacement
Sunforce 80 Led Solar Motion Light — 6V Ni-MH Replacement Battery (SM2P-5SW)
This is a 6V 1500mAh Ni-MH replacement battery for the Sunforce 80 Led Solar Motion Light. It stores the charge collected by the solar panel during daylight and powers the LED array and motion sensor after dark. Fits the 45, 60, and 80 Motion Light models that use the SM2P-5SW cell.
- 45, 60, and 80 Motion Light compatibility: These three Sunforce models share the same 6V battery rail, connector footprint, and BMS input threshold. One cell fits all three because the charging circuit and cut-off voltage are identical across the range.
- Bench tested on actual hardware: We cycled this cell through solar-input charge conditions and confirmed the BMS accepted the charge curve without false cut-off. The cell held voltage through a full simulated overnight discharge at rated load.
- Solar panel positioning matters on this unit: Position the panel perpendicular to direct sunlight. The Sunforce solar circuit requires a minimum input current to overcome the BMS threshold — indirect or partially shaded light can fall below that floor, and the battery will not charge even when ambient light appears bright.
Why the Sunforce motion light goes dark after only a few hours
Ni-MH cells in solar lights degrade through shallow cycling — the panel partially charges the cell each day, then the light draws it down each night. Over time, capacity drops while the cell still accepts charge without complaint. The BMS reports a full charge because voltage looks correct, but actual stored energy is a fraction of the rated 1500mAh. Replacing the cell restores the full charge-to-discharge window the light was sized for.
Motion sensor triggers but LEDs don't illuminate
The motion sensor circuit draws far less current than the LED array, so a degraded cell can still trigger detection while lacking the output voltage to fire the LEDs at full load. When the LED array pulls current, the battery voltage sags below the minimum drive threshold and the LEDs cut out or fail to light at all. Check the battery terminal voltage under load — it should hold at or above 5.4V during LED activation. If it drops below that, the cell needs replacing.