About this replacement
Canon PowerShot G5 X / G1 X Mark III — 3.7V Li-ion Replacement Battery (NB-13L)
This is a 3.7V, 1250mAh Li-ion replacement for the Canon NB-13L battery cell. It fits the PowerShot G5 X, G5 X Mark II, G1 X Mark III, and over 20 other Canon compact camera bodies that share the NB-13L form factor. Voltage and physical dimensions match OEM spec exactly — 42.10 × 29.60 × 9.60mm.
- G5 X and G1 X Mark III shared platform: Canon grouped these bodies around the same battery bay, connector pinout, and BMS handshake protocol. Any body accepting NB-13L shares the same voltage rail and communication lines, so one cell covers the full compatibility list without modification.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a G5 X body. The BMS accepted the cell, reported charge state without error flags, and cutoff at the correct low-voltage threshold without tripping a fault lock.
- First-install charge cycle on camera bodies with BMS display calibration: Canon's battery-remaining indicator maps discharge voltage to a percentage table stored in the camera body. On a fresh replacement cell, run one full charge cycle through the camera body or OEM charger before heavy shooting — this lets the BMS recalibrate its fuel gauge to the new cell's discharge curve.
Flash capacitor recharge sag on a G5 X as the cell ages
The built-in flash on the G5 X draws a sharp current spike each time the capacitor recharges between shots. Early in a cell's life, internal resistance is low enough that this spike pulls voltage down briefly but recovers fast. As the cell ages and internal resistance climbs, that sag deepens and the capacitor takes longer to reach full charge. Practically, this shows up as slower flash recycling and, near end of cell life, the camera may flag low battery during flash-heavy shooting even when the charge indicator shows capacity remaining. Replacing the cell resets internal resistance to a low baseline and restores normal recycling speed.
Battery percentage jumping erratically on the G5 X display
Canon's battery indicator works by comparing real-time cell voltage against a fixed discharge curve programmed into the camera body. A new replacement cell has a slightly different discharge profile than the aged OEM cell the camera learned from — voltage at 50% remaining may sit at a different point than the body expects. The indicator then jumps between readings as the measured voltage crosses lookup-table thresholds unevenly. To resolve this, run the replacement cell from full charge to camera-off shutdown at least once through the camera body, then recharge fully — the body uses that cycle to anchor its gauge to the new cell's actual curve and readings stabilise.