{"product_id":"telefonica-tsm520-replacement-battery-37v-2200mah-li-ion","title":"Telefonica TSM520 Compatible Battery 3.7V 2200mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eTelefonica TSM520 — 3.7V Li-ion 2200mAh Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V Li-ion battery rated at 2200mAh (8.14Wh), built to fit the Telefonica TSM520 smartphone. It replaces a degraded or failed original cell when the phone no longer holds charge or shuts down unexpectedly. Voltage and capacity match the original cell specification.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eTSM520 fit:\u003c\/strong\u003e\n    The TSM520 uses a standard 3.7V single-cell Li-ion configuration. The charge IC on the motherboard expects a specific voltage window and connector pinout — this cell meets both, so the BMS handshake completes normally on first boot.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through charge and discharge on the bench, monitoring BMS cutoff behaviour at both ends of the voltage curve. The protection circuit tripped cleanly at the low-voltage threshold and accepted a full charge without thermal anomaly.\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-to-charge cycle at standard rate. This lets the fuel gauge IC map its coulomb counter against the new cell's actual discharge curve before high-current charging begins on 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 TSM520 after a cell swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis is a voltage cliff problem, not a capacity problem. The TSM520's modem and display draw high instantaneous current, and a new cell with slightly higher internal impedance can drop below the BMS cutoff voltage under that load — even when the fuel gauge still shows charge remaining. The OS reads the fuel gauge, not live cell voltage, so it reports 20–30% right up until the BMS trips. One full discharge-charge cycle at standard rate recalibrates the fuel gauge IC and usually eliminates the premature cutoff.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eTSM520 not powering on after the replacement battery sat in storage\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eLi-ion cells self-discharge during storage. If the cell voltage has dropped below approximately 2.5V per cell, the BMS enters lockout mode to prevent damage and blocks normal boot. Plug the phone into a wall charger — not a PC USB port — and leave it for 20–30 minutes without pressing the power button. The charge IC will trickle current into the cell until it clears the BMS recovery threshold, at which point the phone will boot or show a charging indicator.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43405261242458,"sku":"BWCS-C500XL-1","price":29.99,"currency_code":"USD","in_stock":false},{"title":"Warranty 2 Year","offer_id":43405261275226,"sku":"BWCS-C500XL-2","price":34.99,"currency_code":"USD","in_stock":false},{"title":"Warranty 3 Year","offer_id":43405261307994,"sku":"BWCS-C500XL-3","price":37.99,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-C500XL-big.webp?v=1779370367","url":"https:\/\/batteryweb.com\/products\/telefonica-tsm520-replacement-battery-37v-2200mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}