{"product_id":"fujitsu-esprimo-mobile-v5505-replacement-battery-111v-4400mah-li-ion","title":"Fujitsu Esprimo Mobile V5505 Replacement Battery BTP-BAK8 11.1V","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eFujitsu Esprimo Mobile V5505 Series — 11.1V Li-ion Replacement Battery (BTP-BAK8)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is an 11.1V, 4400mAh (48.84Wh) Li-ion replacement battery for the Fujitsu Esprimo Mobile V5505, V5545, V6505, and V6535 notebooks. It uses OEM part number BTP-BAK8 and shares compatibility across the broader Esprimo Mobile line that runs on the same 11.1V three-cell architecture. Physical dimensions are 206.64 x 50.26 x 24.00mm — check your bay clearance before ordering.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eEsprimo Mobile V-series compatibility:\u003c\/strong\u003e\n    The V5505, V5545, V6505, and V6535 share the same battery bay dimensions, connector pinout, and BMS handshake protocol. Fujitsu used a consistent three-cell 11.1V rail across these Esprimo Mobile variants, which is why one part number covers all of them.\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 load discharge on the V-series platform. The BMS authenticated without fault codes, charge termination triggered correctly at 12.6V, and cell balancing held within spec across all three groups.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFirst-cycle calibration on the V5505:\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 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\"\u003eBIOS reporting poor battery health immediately after fitting a new cell\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe Esprimo Mobile BIOS reads health data from EEPROM stored on the battery's protection circuit, not from a live cell measurement. When a new cell arrives, that EEPROM carries factory default values that don't match the BIOS's learned baseline for the old pack. The system flags this as degraded health even though the cell is new. Run one full discharge-to-hibernate, then a full uninterrupted charge — the BIOS battery learn cycle overwrites the stale EEPROM reference and the health warning clears.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eLaptop shuts down abruptly at 20–30% charge shown\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens when the fuel gauge IC hasn't calibrated against the new cell's actual voltage curve. The OS reads 25% remaining, but the cell hits a voltage cliff under combined CPU and display load that the uncalibrated gauge didn't predict, and the BMS cuts power to protect the cells. It is not a faulty battery — it is a gauge mismatch. Complete two full discharge-to-hibernate and full recharge cycles. After that, the fuel gauge IC recalculates its discharge curve against the real cell and the early shutdowns stop. Verify the fix by checking that the BIOS reports cell voltage above 10.8V at the 20% mark.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43409827332186,"sku":"BWCS-FU1720NB-1","price":65.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43409827364954,"sku":"BWCS-FU1720NB-2","price":76.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43409827397722,"sku":"BWCS-FU1720NB-3","price":85.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-FU1720NB-1.webp?v=1779581113","url":"https:\/\/batteryweb.com\/products\/fujitsu-esprimo-mobile-v5505-replacement-battery-111v-4400mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}