About this replacement
Square LED Light — 7.4V Li-ion Replacement Battery (MP NCM 2s2p)
This is a 7.4V 5200mAh Li-ion replacement battery for the Square LED light. It uses a 2s2p cell configuration — two cells in series for voltage, two in parallel for capacity. Capacity is sourced from product data: 5200mAh / 38.48Wh.
- 2s2p cell configuration: Two cells in series deliver the 7.4V nominal voltage the LED driver needs to maintain consistent output. Two cells in parallel double the capacity. Both strings must stay balanced — the BMS monitors individual cell voltages and will cut output if either string drifts more than roughly 100mV from the other.
- Bench tested on actual hardware: We ran this pack through charge and discharge cycles on the bench. The BMS engaged correctly at low-voltage cutoff, and the protection circuit held under the high-current draw of the turbo drive stage without tripping prematurely.
- Multi-cell replacement rule: In a 2s2p pack, mixing a new battery with an aged original creates an instant cell imbalance. The older cells carry unequal load under high-current draw, accelerating degradation. Always swap the full pack — never pair this battery with a partially used original.
Why the Square LED light dims before the battery indicator drops
The LED driver in this light uses brownout protection to step down output before the BMS hard-cuts the pack. At high draw, cell voltage sags below the driver's minimum input threshold — even though the resting voltage still reads normal. The driver interprets this as low-cell and steps down to protect itself, not the battery. This is expected behaviour, not a fault in the replacement pack.
Battery draining noticeably faster in turbo mode
Turbo mode drives the LED at maximum current — typically five to ten times the draw of standard output. At that current level, the 2s2p pack delivers full rated capacity only at lower C-rates. Under sustained turbo draw, internal resistance causes voltage sag, and the driver steps down output sooner. Switch to mid-output for extended use. If the pack cuts off early, check resting voltage after a full charge — it should read at or above 8.2V.