About this replacement
Dell Venue 8 7000 / 7840 — 3.7V Li-Polymer Replacement Battery (K81RP)
This 3.7V, 5500mAh (20.35Wh) lithium-polymer battery replaces the original K81RP cell in the Dell Venue 8 7000 and Venue 8 7840 tablets. It fits both the 7000 and 7840 variants, which share the same battery bay, connector pinout, and BMS communication protocol. Cross-reference OEM part numbers K81RP, 05PD40, 5PD40, CMMP3, and T02E001 before ordering to confirm fitment.
- Venue 8 7000 and 7840 compatibility: Both models run the same 3.7V battery rail and use an identical flat Li-Polymer form factor measuring 136.00 × 114.86 × 2.80 mm. The BMS handshake and connector are shared across the 7000 and 7840 board revisions, so one cell covers both.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the Venue 8 platform. The BMS accepted the new cell without triggering a fault state, and the charge IC ramped current correctly from the first cycle.
- Fuel gauge recalibration after swap: After installation, run one full discharge to automatic shutoff, then charge uninterrupted to 100%. This resets the fuel gauge IC calibration against the new cell and clears the inaccurate percentage reading that commonly appears after a battery replacement on this tablet.
Venue 8 7840 shutting down at 15–25% battery remaining
This happens because the fuel gauge IC is still calibrated to the voltage curve of the old, degraded cell. When display brightness, WiFi, and active app load hit simultaneously, the combined draw pulls cell voltage below the BMS cutoff threshold earlier than the percentage readout predicts. The tablet interprets this as a legitimate low-voltage shutdown even though the gauge says 20%. One complete discharge-to-zero followed by an uninterrupted charge to 100% realigns the IC's voltage-to-percentage mapping against the new cell's actual curve.
Fast charging not available after battery swap on the Venue 8 7000
The Venue 8 7000 negotiates charge rate over the USB connection before the charge IC commits to a higher current. With a new cell installed, the controller sometimes defaults to standard rate on the first session while it logs an accepted charge cycle. This is not a fault with the replacement cell. Connect the original Dell charger, allow the tablet to complete one full charge uninterrupted, and the fast charge handshake restores on subsequent sessions. If it does not return after one full cycle, verify the charger output reaches the required 5V/2A minimum.