About this replacement
Rapoo 2900 Touch — 3.7V Li-Polymer Replacement Battery (C010721HSP)
This is a 3.7V, 700mAh lithium-polymer battery for the Rapoo 2900 Touch wireless keyboard and mouse combo. It matches OEM part number C010721HSP and fits the slim profile of the 2900 Touch's battery compartment at 59.87 × 37.02 × 4.20mm. When the original cell depletes, this swap restores full wireless function without replacing the entire peripheral.
- 2900 Touch fit confirmation: The 2900 Touch uses a single lithium-polymer cell shared across its keyboard and mouse pairing. The C010721HSP connector pinout and cell dimensions are specific to this combo unit — generic Li-Po cells at the same mAh will not seat or connect correctly.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the 2900 Touch platform and confirmed the BMS accepts charge without fault flags. Voltage held within 3.65–4.18V through the full cycle as expected for Li-Po.
- Post-swap reconnection tip: After fitting a new battery, the 2900 Touch wireless link may not reconnect automatically. Unplug the USB nano-receiver, wait five seconds, and replug it before attempting to use the device — the combo re-initialises the RF pairing on receiver reconnection, not on keypress.
Keyboard pairing lost after battery swap on the 2900 Touch
When the 2900 Touch loses power completely — cell fully discharged — some units drop their stored pairing data. The keyboard's onboard pairing memory is volatile at near-zero voltage, so a full drain before swap can wipe it. After fitting the new cell, hold the Connect button on the underside of the keyboard for three seconds, then replug the USB receiver. The LED on the receiver should blink twice to confirm re-pair at 2.4GHz.
Mouse pointer stuttering before the battery reads as low
The 2900 Touch mouse reduces its RF polling rate as cell voltage drops below roughly 3.5V — this shows up as stutter or lag before any low-battery indicator appears on screen. The wireless module deprioritises polling frequency to conserve power, so the cursor becomes inconsistent. This is end-of-life cell behaviour, not a receiver or driver issue. Fitting a fresh cell and confirming it charges to 4.1–4.2V resolves the stutter immediately.