About this replacement
Becker Traffic Assist Highspeed II 7988 — 3.7V Li-ion Replacement Battery (E4MT081202B22)
This 3.7V, 1200mAh Li-ion cell replaces the original battery in the Becker Traffic Assist Highspeed II 7988 portable GPS navigator. It also fits the BE7988, Traffic Assist Highspeed, and Traffic Assist 7934. Dimensions are 51.00 × 36.53 × 6.57mm — measure your original before fitting if you're unsure.
- Traffic Assist Highspeed platform compatibility: These models share the same 3.7V single-cell architecture, connector pinout, and BMS communication protocol. One cell fits across the range without wiring changes.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a Traffic Assist unit. The BMS handshake completed correctly, charge termination triggered at the expected 4.2V cutoff, and the protection circuit tripped cleanly on over-discharge.
- Cold-start satellite acquisition after fitting: After any full power interruption, the GPS receiver loses its ephemeris data and must perform a cold start. Take the unit outdoors immediately after powering on and let it acquire a satellite fix before driving — first fix can take 5–10 minutes, but subsequent warm starts are under a minute.
GPS accuracy dropping at low battery on the Traffic Assist 7988
When cell voltage drops below roughly 3.5V, some Becker Traffic Assist units reduce receiver sensitivity to protect remaining charge. This shows up as position drift or slower route recalculation — not a software glitch. The GPS chip gets less power, so weaker satellite signals get dropped. Keeping the cell above 3.6V during navigation maintains full receiver performance.
Device shuts off mid-navigation without any low-battery warning
The battery indicator on these units is calibrated to the original cell's discharge curve. A new or partially degraded cell can hit the hard voltage cutoff before the on-screen warning triggers — especially during active GPS and display load. The BMS cuts output at the protection threshold regardless of what the indicator shows. Charge the unit fully to 4.2V, then run one complete navigation session to let the firmware re-learn the discharge curve.