About this replacement
Canon EOS-1D Mark III / Mark IV Series — 11.1V Li-ion Replacement Battery (LP-E4)
This is an 11.1V, 2400mAh (26.64Wh) Li-ion replacement for the Canon LP-E4 battery pack. It fits the EOS-1D Mark III, EOS-1D Mark IV, EOS-1Ds Mark III, and 580EX-II Speedlite, among others. Same voltage, same form factor, same multi-pin connector as the original.
- EOS-1D and 1Ds series compatibility: These bodies share the LP-E4 footprint, the same 11.1V three-cell rail, and an identical BMS handshake protocol. One cell SKU covers all of them without modification.
- Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on an EOS-1D Mark IV body. The BMS accepted the cell, fuel gauge displayed correctly after one full charge cycle, and voltage held flat through sustained burst shooting.
- 580EX-II Speedlite charge current note: The 580EX-II draws recycling current in sharp spikes. Do not mix this battery with a depleted AA pack in a multi-power setup — uneven source impedance causes recycling lag. Use this cell as the sole power source when running the Speedlite from the battery grip.
Why the EOS-1D Mark III rejects a new LP-E4 replacement on first install
The EOS-1D Mark III runs an authentication and calibration check the first time it sees a new cell. If the battery hasn't completed at least one full charge cycle, the body may flag it as unverified and show a warning icon next to the battery indicator. This isn't a fault with the cell — it's the camera's BMS waiting for a baseline capacity reading. Charge the battery fully in the OEM Canon charger or inside the camera body before shooting. After that first complete cycle, the indicator maps correctly and the warning clears.
Battery percentage jumping erratically on the EOS-1D Mark III display
The EOS-1D Mark III maps its fuel gauge to a voltage-threshold table calibrated against the original LP-E4 discharge curve. A replacement cell with a slightly different internal resistance will discharge along a curve the camera doesn't expect, so the percentage readout jumps — sometimes dropping 20% then recovering. This isn't cell failure. Run two full charge-discharge cycles through the camera body and the BMS recalibrates its threshold table to match the new cell's curve. After that, the gauge stabilises. If it still jumps after three cycles, check that resting voltage after a full charge reads at least 12.4V with a multimeter.