About this replacement
ONN Surf Tablet 7" — 3.7V Li-Polymer Replacement Battery (U306992P)
This is a 3.7V, 2000mAh (7.4Wh) lithium-polymer cell that replaces the original battery in the ONN Surf Tablet 7". It fits models 100005206 and 100026191, both of which use the OEM part number U306992P. Swap it in when the original cell no longer holds a charge or the tablet shuts down unexpectedly.
- Fits 100005206 and 100026191: Both ONN Surf Tablet 7" variants share the same 3.7V cell, connector pinout, and charge IC configuration — one battery covers either board revision without modification.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the ONN Surf Tablet 7" platform. The charge IC accepted the new cell without fault codes, and the BMS held voltage within expected range across the full state-of-charge window.
- Fuel gauge recalibration after swap: After fitting this battery, run the tablet down to automatic shutoff, then charge it uninterrupted to 100%. This forces the fuel gauge IC to recalibrate against the new cell and clears the inaccurate percentage readings that commonly appear immediately after a swap.
ONN Surf Tablet 7" shutting down at 15–25% remaining
This happens when the fuel gauge IC is still calibrated to an aged cell with a collapsed voltage curve. A new cell has a steeper voltage drop in the lower state-of-charge range, and the system interprets that drop as a critical threshold before the cell is actually empty. The tablet cuts power because it trusts the old calibration data, not the actual cell voltage. Run one full discharge to automatic shutoff, then charge uninterrupted to 100% — after that cycle, the reported percentage will track the real remaining capacity.
Fast charging not available after battery replacement
The ONN Surf Tablet 7" charge controller completes a USB negotiation handshake on the first accepted charge cycle after a new cell is fitted. Until that handshake completes successfully, the device may default to standard 5V charging rather than any elevated rate the charger supports. This is not a fault with the replacement cell — it resolves after the first full charge cycle is completed without interruption. Use the original ONN charger for that first cycle to ensure the negotiation runs against a known-good voltage source.