Caterpillar B35 Compatible Battery 3.8V 2300mAh Li-Polymer

CATERPILLAR B35 — 3.8V Li-Polymer Replacement Battery (TYS13G02Q)

This 3.8V 2300mAh lithium-polymer cell replaces the OEM battery in the CATERPILLAR B35 rugged smartphone. It matches the original TYS13G02Q specification and fits the B35's battery bay without modification. Capacity figure is taken directly from product data at 8.74Wh.

• B35 platform fit: The B35 uses a sealed rugged chassis with a fixed connector pinout tied to the TYS13G02Q cell format. This replacement matches that connector layout, cell dimensions (72.24 × 43.94 × 4.60mm), and the 3.8V nominal rail the charge IC expects. No pin remapping or adapter needed.
• Bench tested on actual hardware: We cycled this cell through a full charge-discharge sequence on the B35 platform. The BMS accepted the cell without fault flags, charge termination triggered at the correct cutoff voltage, and low-battery warnings fired at the expected threshold.
• First-cycle fuel gauge reset on the B35: After fitting this cell, disable fast charging and run one complete discharge down to automatic shutdown, then charge to 100% uninterrupted. The B35's fuel gauge IC calibrates its coulomb counter against that first full cycle — skipping it leaves the percentage readout unreliable for several days of use.

Why the B35 shuts down suddenly at 20–30% after a cell swap

The B35's fuel gauge IC stores a discharge curve calibrated to the original cell's internal resistance profile. A new cell has a different impedance, so the IC misjudges remaining capacity under load. When the modem fires a high-current burst — during a call or LTE data transfer — voltage sags past the hardware cutoff before the reported percentage reaches zero. The fix is one full uninterrupted discharge-to-shutdown cycle followed by a full charge, which forces the coulomb counter to rebuild its curve against the new cell.

B35 not powering on after the replacement cell sat in storage

Li-polymer cells self-discharge in storage. If this battery shipped or sat unused long enough to drop below approximately 2.5V per cell, the BMS enters lockout mode to prevent damage and will not pass current to the device. The B35 will show no response — no boot logo, no charge indicator. Connect the phone to a wall charger rated at least 5V 1A and leave it for 20–30 minutes without pressing the power button; the charge IC needs time to trickle current into the cell and bring it above the BMS recovery threshold, typically around 2.9V, before normal charging resumes.