About this replacement
Cricket Outlast / U680AC — 3.85V Li-Polymer Replacement Battery (516793)
This is a 3.85V, 5800mAh Li-Polymer cell replacing part number 516793 in the Cricket Outlast (U680AC). It fits the original battery bay and connects to the same charge IC and fuel gauge circuit the phone uses from the factory. If your Outlast is shutting down early, draining fast, or no longer holding a full charge, this cell swaps directly into the existing housing.
- Outlast / U680AC fitment: Both model designations share the same physical chassis, battery bay dimensions (94.30 × 67.20 × 5.10mm), and 3.85V charge rail. The connector pinout and BMS handshake point are identical across the Outlast production run, so one cell covers both identifiers.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on a 3.85V Li-Polymer tester. The BMS accepted the charge IC handshake on the first cycle, held within ±0.02V of rated terminal voltage across the mid-SOC range, and triggered protection cutoff cleanly at the low-voltage threshold — no latching fault observed.
- Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. The phone's fuel gauge IC was calibrated to the discharge curve of the original cell. Running one slow cycle gives the coulomb counter time to map the new cell's curve before fast-charge current is applied to an uncalibrated state-of-charge estimate.
Sudden shutdown at 20–30% on the Outlast after a cell swap
This is a voltage cliff issue, not a capacity defect. When the modem fires during a call or the display runs at full brightness, current draw spikes sharply. A new cell with an uncalibrated fuel gauge IC can report 25% SOC while actual terminal voltage drops below the hardware protection threshold under that load — the phone cuts power to protect the cell. The fix is the same slow first cycle described above: let the coulomb counter track a full discharge and recharge at standard current before the phone trusts its own percentage reading. After one full cycle, the reported percentage and actual cell voltage should track together through normal use.
Phone won't power on after the replacement cell sat in storage
Li-Polymer cells self-discharge in storage. If this cell sat below approximately 2.5V per cell before installation, the BMS may have tripped its deep-discharge lockout to prevent damage to the chemistry. The phone will show nothing — no charging animation, no response to the power button. Connect the phone to a wall charger (not a USB hub) and leave it for 20–30 minutes without pressing anything; the charge IC needs time to trickle current into the cell until BMS voltage clears the lockout threshold. Once the cell climbs above roughly 3.0V, the BMS re-initialises and normal charging resumes.