{"product_id":"asus-fx504-replacement-battery-114v-4200mah-li-polymer","title":"Asus FX504 B31N1726 Replacement Battery 11.4V 4200mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eAsus FX504 Series — 11.4V Li-Polymer Replacement Battery (B31N1726)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is an 11.4V, 4200mAh (47.88Wh) Li-Polymer battery for the Asus TUF Gaming FX504 series laptop. It fits FX504, FX504G, FX504GE, and related variants using OEM part B31N1726. Install it when the original cell no longer holds a charge or the laptop won't run unplugged.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eFX504 series compatibility:\u003c\/strong\u003e\n    These models share the same 11.4V three-cell Li-Polymer configuration, connector pinout, and BMS communication protocol. The FX504G and FX504GE use the same battery bay and charge controller, so one cell covers the full lineup without modification.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell through charge and discharge cycles on an FX504GE unit. The BMS handshake completed on first boot, charge current stepped down correctly at 80% and 95%, and the protection circuit tripped cleanly at the low-voltage threshold without hard shutdown.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-install calibration on the FX504:\u003c\/strong\u003e\n    After fitting, run the laptop down to hibernate cutoff on battery alone — no AC during discharge. Then charge uninterrupted to 100% without waking the machine. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap 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 FX504 shuts down at 20–30% remaining after a battery swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe FX504's fuel gauge IC builds a discharge curve against the original cell's EEPROM data. A new cell has different internal resistance, so the IC's voltage-to-capacity map is wrong from the start. Under full CPU and display load, the cell voltage drops faster than the old curve predicts, and the system reads it as critically low — triggering shutdown well above actual depletion. Run two full discharge-to-hibernate cycles followed by uninterrupted full charges. The fuel gauge IC recalibrates against the new cell's actual curve and the early shutdowns stop.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eBIOS reporting battery health as poor or capacity as 0% after replacement\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe FX504 BIOS reads health data from the cell's EEPROM — the old cell's wear data does not clear when you swap the battery. On first boot with a new cell, the BIOS compares the fresh cell's voltage signature against stored degradation records and flags a mismatch as poor health. This is a BIOS learn cycle fault, not a faulty cell. Boot into Windows, open MyASUS or the ASUS Battery Health Charging utility, and let the system complete one full charge cycle — the BIOS rewrites its battery reference data and the health warning clears.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43409644486746,"sku":"BWCS-AUF726NB-1","price":63.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43409644519514,"sku":"BWCS-AUF726NB-2","price":75.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43409644552282,"sku":"BWCS-AUF726NB-3","price":83.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-AUF726NB_1.webp?v=1779579964","url":"https:\/\/batteryweb.com\/products\/asus-fx504-replacement-battery-114v-4200mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}