Nightstick XPP-5582RX Replacement Battery 3.7V 10000mAh

Nightstick XPP-5582RX / XPR-5582GX — 3.7V Li-ion Replacement Battery (5582-BATT)

This is a 3.7V, 10000mAh (37Wh) lithium-ion replacement for the Nightstick 5582-BATT. It fits the XPP-5582RX and XPR-5582GX rechargeable flashlights used by law enforcement and emergency responders. Capacity figure is taken from the product specification — not estimated from web sources.

• XPP-5582RX and XPR-5582GX compatibility: Both lights share the same battery bay dimensions, 3.7V nominal rail, and BMS handshake protocol — that's why a single pack covers both models. The connector pinout and cell geometry are identical across the pair.
• Bench tested on actual hardware: We cycled this pack through the XPP-5582RX driver at full turbo output. The BMS held steady across high-current draw, with cutoff triggering at the correct low-voltage threshold rather than stepping down prematurely.
• Full-charge storage before extended standby: Li-ion cells in standby flashlights self-discharge slowly over weeks. Store this pack at roughly 50–60% charge if the light won't be used for more than a month — a fully charged cell sitting idle for extended periods accelerates electrolyte degradation faster than partial-state storage.

Why the XPP-5582RX dims before the battery indicator drops

The XPP-5582RX driver monitors cell voltage directly, not the fuel-gauge percentage shown on the indicator. When voltage sags under the high current draw of turbo mode, the driver steps output down to protect the cell — even if the indicator still reads partial charge. This is a deliberate brownout protection response, not a fault. Switching to a lower output mode at this point restores stable brightness because current draw drops and voltage sag stops. If the light dims immediately after a fresh charge, check that the battery contacts are clean and seated fully.

Turbo mode cuts out far sooner than standard mode — what's happening

Turbo mode on the XPP-5582RX draws substantially more current than standard or low modes — the cell voltage sags under that load faster than it does at moderate output. The driver interprets this sag as a low-voltage event and steps the output down or cuts out entirely, even though the cell still holds significant capacity at lower draw rates. This is normal behaviour for a single high-capacity li-ion cell driving a high-output LED at its maximum rating. If turbo runtime is significantly shorter than expected after a full charge, verify the charge cycle completed fully and the battery reached 4.2V before use.