Kyocera U4R Replacement Battery BP-1100S 3.7V 1100mAh

Kyocera U4R Series — 3.7V Li-ion Replacement Battery (BP-1100S)

This is a 3.7V, 1100mAh lithium-ion replacement for the original BP-1100S battery. It fits the Kyocera U4R, U4RB, and U4RBK digital cameras. Same voltage, same footprint, same connector pin layout as the factory cell.

• U4R, U4RB, U4RBK compatibility: All three models share the same battery bay dimensions, connector pinout, and BMS voltage thresholds — 3.7V nominal, 4.2V charge ceiling. One cell fits all three without modification.
• Bench tested on actual hardware: We cycled this cell through the U4R body and an OEM-compatible charger. The BMS accepted charge handshake on first insertion and held charge termination at 4.2V without deviation.
• First-cycle calibration on the U4R body: Before heavy shooting, run the first full charge directly through the camera body rather than a standalone charger. The U4R's battery indicator maps its percentage display to a charge curve it reads during that first in-body cycle — skipping it can cause the indicator to read inaccurately for several sessions.

Why the U4R battery percentage jumps erratically after a replacement cell is installed

The U4R uses a voltage-threshold method to estimate remaining charge. The camera maps specific voltage levels — typically 3.6V, 3.75V, and 4.0V — to display steps on its indicator. A new cell has a slightly different discharge curve than a worn original, so the camera reads voltage drops at unexpected points and the percentage jumps. This corrects itself after one or two full discharge-and-charge cycles. Run the battery down to auto-shutoff, then charge fully to 4.2V to let the camera recalibrate its voltage map.

U4R showing dead battery icon immediately after inserting a charged replacement

This happens when the cell voltage sits just below the camera's minimum recognition threshold — usually under 3.5V — after shipping or storage. The camera sees insufficient voltage on the sense pin and throws the dead-battery indicator before attempting to read capacity. Remove the cell, place it in a standalone charger, and bring it up to at least 3.6V. Once it clears that threshold, the U4R body will recognise it normally on reinsertion.