About this replacement
Dell Venue 8 Pro 3845 — 3.7V Li-Polymer Replacement Battery (7KJTH)
This is a 3.7V, 4100mAh (15.17Wh) lithium-polymer battery for the Dell Venue 8 Pro 3845 tablet. It replaces OEM part number 7KJTH and fits the internal battery bay of the 3845 model specifically. The cell dimensions are 135.9 × 82.70 × 3.80 mm — measure before ordering if you are unsure which 8-inch Venue variant you have.
- Venue 8 Pro 3845 fitment: The 3845 uses a flat Li-Polymer pouch cell with a specific connector orientation and BMS communication line that differs from other Venue 8 variants. This battery matches that connector and BMS handshake — do not assume other Venue 8 Pro models use the same cell.
- Bench tested on actual hardware: We cycled this battery through charge and discharge on the 3845 board. The BMS accepted the cell without fault codes, and the charge IC brought it to full termination voltage without interruption.
- Fuel gauge IC reset after installation: After fitting, run the tablet down to automatic shutoff — do not force-power it off — then charge it uninterrupted to 100%. This single cycle recalibrates the fuel gauge IC against the new cell and corrects the inaccurate percentage readings that appear immediately after a swap.
Why the Venue 8 Pro 3845 shuts down between 15% and 25% remaining
The 3845 pulls simultaneous load from the display, WiFi radio, and Windows background processes during active use. At around 3.5V cell voltage, this combined draw creates a brief voltage sag that the BMS reads as a critically low condition and triggers a hard shutoff — even though the reported percentage still shows double digits. A degraded original cell hits this cliff earlier and more aggressively. Replacing the cell and running one full recalibration cycle moves the cutoff point back to where it belongs.
Fast charging not available after battery swap on the Venue 8 Pro 3845
Windows may report slow or standard charging only after a battery replacement, even with the original Dell charger. The charge IC on the 3845 board needs one completed accepted charge cycle — from a low state of charge to 100% without interruption — before it re-establishes the correct charging profile with the new cell. Do not interrupt the first charge. After that cycle completes, disconnect, restart the tablet, reconnect the charger, and confirm charge rate in Device Manager under the battery entry.