GODOX VB18 Replacement Battery 11.1V 2000mAh Li-ion V860II

GODOX V860II Series — 11.1V Li-ion Replacement Battery (VB18)

The VB18 is an 11.1V 2000mAh (22.2Wh) Li-ion cell that powers the GODOX V860, V860II, V850, and V850II speedlights. It feeds the flash's capacitor charging circuit, which determines how fast the unit recycles between shots. Voltage and cell geometry match the OEM spec directly.

• V860 and V850 series compatibility: All four models — V860, V860II, V850, V850II — share the same battery bay dimensions, 11.1V nominal voltage rail, and BMS handshake protocol. One cell format covers the full lineup because GODOX kept the power platform consistent across generations.
• Bench tested on actual hardware: We ran this cell through sustained full-power firing sequences on the V860II. The BMS held voltage above the capacitor recharge threshold across repeated cycles, and the protection circuit tripped cleanly at the correct low-voltage cutoff without false triggers mid-session.
• First-fit initialisation on the V860II: After seating a new cell, power the flash fully off and back on from cold before firing — do not hot-swap mid-session and shoot immediately. The BMS handshake that sets the charge curve completes only from a full cold start, not from a warm insert.

Flash output stepping down after 10–15 full-power shots

At full power, the V860II's capacitor draws a sharp recharge current spike after every pop. That spike pulls the cell voltage down briefly — normal behaviour for any Li-ion under high instantaneous load. When the cell is aged or cold, that sag crosses the BMS low-voltage threshold and the flash steps down output to protect the cell. A fresh cell with lower internal resistance handles the recharge spike without sagging past the cutoff. If output stepping persists beyond the first five cycles on a new cell, check that the cell seated fully and the contacts are clean.

Recycle time noticeably slower than the original cell

A new Li-ion cell ships with slightly elevated internal resistance until the chemistry stabilises across a few charge-discharge cycles. Higher resistance means the capacitor recharges at a lower current rate, which shows up as a longer wait between flashes. This is not a fault — five full conditioning cycles (drain to cutoff, full recharge) bring internal resistance down to operating spec. After conditioning, recycle time on the V860II should match or approach the original cell's performance at the same power setting.