{"product_id":"benq-joybook-s52-replacement-battery-108v-4400mah-li-ion","title":"BenQ JoyBook S52 Replacement Battery SQU-409 10.8V 4400mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eBenQ JoyBook S52 Series — 10.8V Li-ion Replacement Battery (SQU-409)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 10.8V, 4400mAh Li-ion battery replaces the original SQU-409 cell in the BenQ JoyBook S52, S52E, S52W, and S53 notebooks. It restores untethered operation on this mid-2000s ultraportable when the factory cell no longer holds a usable charge. Voltage and connector match the original spec exactly.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eJoyBook S52 series fit:\u003c\/strong\u003e\n    The S52, S52E, S52W, and S53 all share the same battery bay geometry, 10.8V rail, and connector pinout. The BMS handshake protocol is identical across the series, so one cell fits all four variants without modification.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through full charge and discharge on a JoyBook S52 chassis. The BMS accepted the cell on first contact, charge termination triggered correctly at 12.6V, and the protection circuit responded normally to load spikes during CPU-intensive tasks.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-install calibration on the JoyBook S52:\u003c\/strong\u003e\n    After installing, run one full discharge to hibernate-cutoff then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after swapping cells on this platform.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the JoyBook S52 BIOS reports poor battery health after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe JoyBook S52 BIOS reads health data stored in the battery's EEPROM from the previous charge cycles. When a new cell arrives, that EEPROM counter reflects fresh or reset data that conflicts with what the BIOS expects for a \"normal\" battery. The system flags this mismatch as degraded health rather than a new cell. Running a full discharge-to-hibernate followed by an uninterrupted charge to 100% forces the BIOS to rewrite its learned parameters against the new cell's actual chemistry.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eJoyBook S52 shutting down at 20–30% charge shown on screen\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens when the fuel gauge IC's capacity map no longer matches the new cell's real discharge curve. Under combined CPU and display load, the cell voltage drops faster than the old map predicts, hitting the BMS low-voltage cutoff while the OS still shows charge remaining. The fix is calibration: drain the battery fully until the laptop hibernates on its own, then charge to 100% without interruption — repeat this twice. After two full cycles the fuel gauge IC recalibrates and the shutdown-at-20% behaviour stops.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43410824200282,"sku":"BWCS-PB5340NB-1","price":73.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43410824233050,"sku":"BWCS-PB5340NB-2","price":85.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43410824265818,"sku":"BWCS-PB5340NB-3","price":94.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-PB5340NB-1.webp?v=1779581287","url":"https:\/\/batteryweb.com\/products\/benq-joybook-s52-replacement-battery-108v-4400mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}