Bayco XPP-5570 Compatible Battery 3.7V 2600mAh Li-ion

Bayco XPP-5570 / XPR-5572 — 3.7V Li-ion Replacement Battery (5572-BATT)

This is a 3.7V, 2600mAh (9.62Wh) lithium-ion battery for the Bayco XPP-5570 and XPR-5572 rechargeable flashlights. It slots directly into the battery compartment and communicates with the onboard LED driver as the original cell does. Use this when your existing cell no longer holds a charge through a full shift.

• XPP-5570 and XPR-5572 compatibility: Both models run the same 3.7V single-cell platform with an identical connector footprint and driver handshake. The cell dimensions — 116.00 × 47.65 × 26.20mm — match the bay geometry in both lights, so no adapters or modifications are needed.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the XPP-5570 driver. The BMS held stable voltage under high-draw output and tripped correctly at the low-voltage cutoff threshold before output could damage the LED driver circuit.
• Driver load tip for the XPP-5570: Bayco's XPP-5570 driver steps down output aggressively as cell voltage drops. If you are returning the light to service after storage, run a full charge cycle before use — a partially charged cell can trigger the driver's brownout protection and lock the light into a reduced output mode from the first switch-on.

Turbo mode draining the XPP-5570 battery faster than expected

Turbo mode on the XPP-5570 pulls significantly more current than standard or low modes — often five to ten times the draw. A 2600mAh cell that lasts through extended use on standard output will deplete much faster under turbo. This is not a fault with the cell. The LED driver is simply pulling the cell harder to sustain peak lumen output. If turbo runtime feels short, switch to high or standard mode for sustained use and reserve turbo for short bursts only.

Flashlight cycling through modes on its own near end of charge

When the cell voltage drops toward the driver's lower operating threshold — typically around 3.0V — some LED drivers on the XPP-5570 will begin cycling output modes rather than maintaining a steady mode. This is brownout protection behaving as intended: the driver cannot sustain the selected mode at low voltage, so it steps down or cycles. The fix is straightforward — switch to a lower mode manually as soon as you notice cycling. Check cell voltage with a multimeter; a reading below 3.2V under load confirms the cell needs a charge.