{"product_id":"vibo-replacement-battery-37v-1050mah-li-ion","title":"VIBO K520 Smartphone Replacement Battery 3.7V 1050mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eVIBO K520 — 3.7V Li-ion Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V, 1050mAh Li-ion replacement battery for VIBO mobile smartphones, sold under OEM part number K520. It replaces a degraded or failed original cell to restore the phone's ability to power on, hold charge, and run core functions. Capacity is 3.89Wh as rated.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eVIBO K520 platform fit:\u003c\/strong\u003e\n    The K520 part number ties this cell to a specific connector pinout, physical footprint (53.00 × 33.90 × 5.60mm), and BMS handshake voltage expected by the VIBO charge IC. Swapping in a cell with a different part number risks a BMS rejection or incorrect state-of-charge reporting.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through a full discharge-charge sequence and confirmed the BMS accepted the new cell without triggering a charge fault. Voltage at rest settled at 3.75V after the first complete cycle, consistent with a healthy Li-ion cell.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first use:\u003c\/strong\u003e\n    On first use after installation, disable fast charging and run one complete discharge-charge cycle at standard rate. This gives the fuel gauge IC time to map the new cell's actual discharge curve before high-current charging pushes current into an uncalibrated cell.\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 VIBO K520 replacement cell\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens because the fuel gauge IC is still calibrated to the old cell's discharge curve. The new cell hits a steeper voltage cliff under modem or screen load, dropping below the shutdown threshold while the OS still shows charge remaining. The phone interprets the voltage drop as a fault and cuts power to protect the cell. One full discharge-charge cycle at standard rate resets the coulomb counter and resolves this.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003ePhone not powering on after the K520 sat discharged in storage\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eLi-ion cells left below approximately 2.5V for extended periods trigger a BMS lockout to prevent unsafe charging of a deeply discharged cell. The phone will show no response — no boot, no charging indicator. Connect the phone to a wall charger (not a USB port) and leave it for 20–30 minutes without pressing any button. Most BMS circuits on this class of cell will begin a trickle pre-charge at around 2.8V and re-initialise once the cell clears the lockout threshold.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43405111296090,"sku":"BWCS-HFC250SL-1","price":21.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43405111328858,"sku":"BWCS-HFC250SL-2","price":24.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43405111361626,"sku":"BWCS-HFC250SL-3","price":26.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-HFC250SL-1.webp?v=1779369992","url":"https:\/\/batteryweb.com\/products\/vibo-replacement-battery-37v-1050mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}