ONN Surf 8" 3rd Gen Replacement Battery 3.8V 5000mAh

ONN Surf 8" 3rd Gen — 3.8V Li-Polymer Replacement Battery (U28100115PV)

This is a 3.8V, 5000mAh Li-Polymer replacement battery for the ONN Surf 8" 3rd generation tablet (model 100071483). It replaces OEM part U28100115PV and powers the tablet's display, processor, and wireless radios. Fit the battery when the original no longer holds a charge or has swollen.

• Surf 8" 3rd Gen compatibility: The ONN 100071483 uses a flat Li-Polymer cell at 3.8V nominal — the same voltage rail the charge IC and PMIC expect. Swapping in a cell at the wrong voltage trips the protection circuit immediately. This cell matches the OEM spec exactly, so the board communicates with it normally.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the ONN Surf 8" platform. The BMS accepted the cell without error flags, and the charge IC completed a full CC/CV cycle without cutting off early. Cell temperature stayed within normal range throughout.
• Fuel gauge recalibration after install: After fitting this battery, run the tablet down to automatic shutoff — do not force it off manually. Then charge uninterrupted to 100% without using the tablet. This single full cycle resets the fuel gauge IC calibration against the new cell and clears the inaccurate percentage readings that almost always appear after a battery swap.

Why the ONN Surf 8" shuts down between 15% and 25% remaining

This happens when the fuel gauge IC is still calibrated to the old, degraded cell. The old cell had a steep voltage cliff at low charge — the IC learned that cliff as "empty." With a fresh cell, actual capacity runs deeper, but the IC still triggers shutdown at the same learned voltage point. Running one complete discharge-to-shutoff cycle followed by a full uninterrupted charge teaches the IC the new cell's voltage curve. After that cycle, shutdowns at 15–25% stop.

Fast charging not available after battery swap

Some ONN Surf 8" units won't negotiate fast charge on the first cycle after a battery swap. The USB-PD controller holds at standard 5V input until it completes one accepted full charge cycle with the new cell. This is a firmware-level handshake, not a fault with the battery or the charger. Complete one full charge from low to 100% using the original charger, and USB-PD negotiation resumes on the next charge.