About this replacement
Logitech Keys-To-Go / IK1041 — 3.7V Li-Polymer Replacement Battery (533-000099)
This 3.7V 180mAh Li-Polymer battery replaces the internal cell in the Logitech Keys-To-Go portable Bluetooth keyboard, including units sold under model reference IK1041. It matches OEM part numbers 533-000099 and AHB222535PJT. At 36.76 x 24.50 x 3.45mm, the footprint is exact — no trimming or folding of the flex tab required during installation.
- Keys-To-Go and IK1041 fitment: Both model names refer to the same hardware revision. The keyboard uses a single flat Li-Polymer cell wired directly to the Bluetooth controller board. Voltage tolerance on that board is narrow — a cell outside the 3.7V nominal range will cause the keyboard to pair but drop keystrokes intermittently before fully refusing to connect.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the Keys-To-Go board and monitored BMS cutoff behaviour. The protection circuit tripped cleanly at the low-voltage threshold and accepted a full charge from the keyboard's USB charging port without thermal event or error state.
- USB charging after cell swap: The Keys-To-Go charges through its Micro-USB port, not via the cell leads directly. After installing the new cell, connect the keyboard to a USB power source and allow a full charge cycle before pairing. A partially charged new cell can cause the Bluetooth module to under-perform during the initial handshake.
Bluetooth pairing lost after the battery goes flat on the Keys-To-Go
When the Li-Polymer cell drains completely, the keyboard's Bluetooth module loses its stored pairing data on some firmware versions. This happens because the pairing state is held in volatile memory backed by the cell — not in persistent flash. After fitting a replacement battery and charging, hold the Bluetooth button for six seconds until the LED flashes rapidly, then re-pair from your device's Bluetooth settings as if connecting for the first time.
Keys-To-Go connects but drops keystrokes intermittently
Intermittent keystroke drops on an otherwise paired keyboard usually point to the cell voltage sagging under the polling load of the Bluetooth transmitter. At end-of-life, a degraded 180mAh cell can no longer sustain the brief current draw each transmission requires, and the Bluetooth module resets mid-burst. Check the cell voltage directly — anything below 3.5V under light load confirms the cell is the cause. Replace the battery and verify resting voltage reads 3.7V after a full charge.