ONN ONA19TB002 Tablet Compatible Battery 3.7V 3400mAh

ONN ONA19TB002 Tablet 8 — 3.7V Li-Polymer Replacement Battery (YB2798103)

This is a 3.7V, 3400mAh Li-Polymer replacement battery for the ONN ONA19TB002 Tablet 8 (also listed as model 100005207). It replaces OEM part YB2798103 when the original cell no longer holds a useful charge. Capacity is rated at 12.58Wh — matching the original specification.

• ONA19TB002 / Tablet 8 / 100005207 fitment: These three model numbers refer to the same ONN 8-inch tablet hardware platform. They share the same battery bay geometry, connector pinout, and charge IC protocol — one cell fits all three.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the ONA19TB002 board. The charge IC accepted the new cell without fault codes, and the BMS reported correct voltage at each state-of-charge step.
• Fuel gauge recalibration after swap: After installing this battery, run the tablet down to automatic shutoff, then charge it uninterrupted to 100% without using the device. This gives the fuel gauge IC one full reference cycle against the new cell and clears the inaccurate percentage readings that almost always appear immediately after a battery replacement.

ONA19TB002 shutting down at 15–25% remaining

This is a voltage cliff issue, not a capacity fault. When the display backlight and Wi-Fi radio draw current simultaneously, the cell voltage drops sharply near the low end of the charge curve. The charge IC reads that voltage drop as a critically low cell and triggers a protective shutdown before the percentage counter reaches zero. One full discharge-to-shutoff cycle followed by an uninterrupted charge to 100% recalibrates the fuel gauge and raises the shutdown threshold back to a realistic voltage floor — typically resolving cutoffs above 10%.

Fast charging not available after battery swap on the ONA19TB002

After a battery replacement, the charge IC on the ONA19TB002 may default to a conservative 5V standard charge rate on the first cycle. This happens because the controller has lost its learned profile for the new cell and reverts to a safe fallback. Completing one full accepted charge cycle — from shutoff to 100% on the original ONN charger — allows the IC to negotiate the correct charge rate. If fast charging still does not activate after that cycle, verify the cable and adapter support the required current rating for the ONN charger specification.