WayteQ X820 GPS Navigator Replacement Battery 3.7V 800mAh

WayteQ X820 / X850 — 3.7V Li-ion Replacement Battery (554844P)

This is a 3.7V, 800mAh Li-ion cell replacing OEM part 554844P in the WayteQ X820 and X850 portable GPS navigators. It fits the slim battery bay in both units without modification. Voltage and physical dimensions match the original: 47.90 × 44.10 × 5.55mm.

• X820 and X850 compatibility: Both models share the same battery bay geometry, connector pinout, and 3.7V supply rail. One cell covers both units — no adapter or wiring change needed.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the X820 platform. The protection circuit engaged correctly at low-voltage cutoff, and the device charged normally from the OEM USB cable without throwing a fault.
• Cold-start behaviour after fitting: After any full power interruption, the GPS receiver performs a cold start — expect the first satellite fix to take 5–10 minutes. Power the unit on outdoors in open sky immediately after fitting and leave it running until it acquires a fix. Subsequent warm starts after normal use will lock on in under a minute.

GPS accuracy reduced at low battery on the X820

When cell voltage drops toward 3.5V, some GPS units step down receiver sensitivity to reduce current draw. On the X820 this shows as wider position scatter and slower track updates during active navigation. The fix is not a settings change — it is a voltage issue. Keeping the cell above 3.6V during use maintains full receiver sensitivity.

Device shuts off without warning before the battery indicator hits empty

The X820 battery gauge reads fuel-level estimates calibrated to the original cell's discharge curve. A new or different-capacity cell will have a slightly different curve, so the on-screen indicator can show one bar remaining when the cell is already near cutoff voltage. The BMS then trips — hard shutdown, no warning. Run two or three full charge-discharge cycles on the new cell and the gauge will recalibrate to a more accurate reading. After recalibration, the low-battery warning should trigger closer to the real 3.5V cutoff threshold.