Logitech Ultratin Keyboard Cover 533-000070 Replacement Battery 3.7V 500mAh

Logitech Ultratin Keyboard Cover Y-R0032 — 3.7V Li-Polymer Replacement Battery (533-000070)

This 3.7V, 500mAh Li-Polymer battery replaces the original internal cell in the Logitech Ultratin Keyboard Cover. It fits the Y-R0032 model, the slim wireless keyboard cover made for tablet use. The battery restores wireless typing function when the original cell no longer holds a usable charge.

• Y-R0032 platform fit: The Ultratin Keyboard Cover uses a flat Li-Polymer cell to stay within its slim profile. The 533-000070 cell matches the voltage rail and physical footprint the keyboard's charging circuit and BMS expect. Swapping in a different voltage or cell geometry causes incorrect charge termination or physical fit issues.
• Bench tested on actual hardware: We cycled this cell through the Ultratin's onboard charge controller and confirmed the BMS reached full charge termination without fault flags. Discharge held stable across the polling cycles the keyboard uses for Bluetooth transmission.
• Bluetooth polling draw on the Ultratin: The Ultratin stays in a low-power advertising state when idle, but active keystrokes spike current draw briefly on each Bluetooth event. Keep the keyboard paired and the tablet nearby — extended range forces higher transmit power and drains this 500mAh cell faster than normal desk use.

Why the Ultratin Keyboard Cover loses Bluetooth pairing after the battery dies completely

When the Li-Polymer cell drops below the BMS cutoff threshold — typically around 2.7V — the keyboard loses all power, including volatile memory holding the Bluetooth pairing profile. The Ultratin does not store pairing data independently of the main power rail. Once a new cell is installed and the keyboard powers on, it presents as a new unrecognised device. You will need to delete the old pairing on the tablet and re-pair from scratch using the keyboard's Bluetooth connect button.

Keyboard powers on but keystrokes are delayed or dropping characters

Bluetooth polling rate on the Ultratin degrades before the battery hits full cutoff. At around 3.4V the firmware reduces transmission frequency to conserve charge, which shows up as input lag or dropped characters rather than a clean shutdown. This is normal end-of-life behaviour, not a pairing or tablet fault. Install the new cell, confirm the keyboard charges via its USB port, and test at full charge — keystroke response returns to normal once the cell voltage is above 3.7V.