{"product_id":"caterpillar-cat-s52-replacement-battery-38v-2900mah-li-polymer","title":"APP00307 CATERPILLAR CAT S52 Replacement Battery 3.8V 2900mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eCATERPILLAR CAT S52 — 3.8V Li-Polymer Replacement Battery (APP00307)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.8V, 2900mAh Li-Polymer replacement battery for the CATERPILLAR CAT S52 rugged smartphone. It carries OEM part number APP00307 and is a direct cell swap for units where the original battery has swollen, lost capacity, or failed outright. Capacity figure is 11.02Wh.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eCAT S52 fitment:\u003c\/strong\u003e\n    The S52 uses a sealed chassis with a specific connector pinout and BMS handshake tied to the APP00307 cell specification. Swapping to a cell with a mismatched voltage curve or different pin assignment will trigger charge rejection at the power management IC level.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell on the S52 platform and confirmed the BMS accepted the handshake, charge current ramped correctly through CC\/CV stages, and no protection trip occurred at full charge or under modem load.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first cycle:\u003c\/strong\u003e\n    On first use after installation, disable fast charging and allow one complete discharge-charge cycle at standard rate. This gives the fuel gauge IC a clean discharge curve to map against the new cell before high-current charging begins on an uncalibrated coulomb counter.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eSudden shutdown at 20–30% on the CAT S52 after a cell swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe S52's fuel gauge IC builds its state-of-charge model against the original cell's discharge curve stored in non-volatile memory. A new cell has a slightly different internal resistance profile, so the IC misjudges remaining capacity and the phone hits a voltage cliff under modem or screen load before the percentage reaches zero. The BMS interprets the voltage drop as a hard undervoltage event and cuts power immediately. One full discharge-charge cycle at standard rate lets the coulomb counter reset and re-anchor to the new cell's actual curve.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eUSB fast charge not activating after battery replacement on the S52\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eOn the first charge cycle after installation, some S52 units hold the charge IC in standard 5V mode rather than negotiating a higher voltage via the USB-PD or proprietary fast-charge protocol. This happens because the BMS flags the new cell as unverified and applies a conservative current limit until it logs a successful full cycle. Charge the phone once from near-empty to 100% at standard rate using the original cable and wall adapter. After that cycle completes, fast charge typically resumes on the next plug-in.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43306858086490,"sku":"BWCS-CAS520SL-1","price":39.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43306858119258,"sku":"BWCS-CAS520SL-2","price":46.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43306858152026,"sku":"BWCS-CAS520SL-3","price":51.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-CAS520SL_1.webp?v=1777768811","url":"https:\/\/batteryweb.com\/products\/caterpillar-cat-s52-replacement-battery-38v-2900mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}