{"product_id":"hyundai-ts21b-replacement-battery-37v-1000mah-li-ion","title":"Hyundai TS21B Replacement Battery 3.7V 1000mAh Li-ion","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eHyundai TS21B — 3.7V Li-ion Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V Li-ion cell rated at 1000mAh (3.7Wh), built to fit the Hyundai TS21B smartphone. It replaces the original cell when capacity has dropped, charge no longer holds, or the phone shuts off unexpectedly. Voltage and connector match the TS21B's charge IC and BMS requirements.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eTS21B cell compatibility:\u003c\/strong\u003e\n    The TS21B runs a single-cell 3.7V nominal Li-ion configuration. The replacement cell matches that voltage rail and physical connector — the BMS negotiates charge current the same way it does with the factory cell.\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 under typical smartphone load profiles. The BMS accepted the cell without error flags, and charge termination triggered correctly at full voltage.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration after swap:\u003c\/strong\u003e\n    On first use after installation, disable fast charging for one complete discharge-charge cycle. This gives the fuel gauge IC time to map the new cell's discharge curve before high-current charging pushes current into an uncalibrated state.\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 TS21B after a cell swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens because the fuel gauge IC is still reading the old cell's discharge curve. The new cell hits a voltage cliff under modem or screen load before the gauge reaches zero. The phone interprets the voltage drop as a fault and shuts down — not a defective cell, but an uncalibrated gauge. Run one full discharge to near-zero and a full charge to 100% to let the coulomb counter reset against the new cell's actual curve.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eTS21B percentage jumping erratically after replacement\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eErratic percentage readings on the TS21B after a cell swap point to the fuel gauge IC recalibrating against new internal resistance values. The coulomb counter was tuned to the worn original cell and now overestimates or underestimates state of charge. This stabilises after one or two full discharge-charge cycles. Charge from below 5% to 100% without interruption to accelerate recalibration.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43405154058330,"sku":"BWCS-AU8200SL-1","price":23.99,"currency_code":"USD","in_stock":false},{"title":"Warranty 2 Year","offer_id":43405154091098,"sku":"BWCS-AU8200SL-2","price":26.99,"currency_code":"USD","in_stock":false},{"title":"Warranty 3 Year","offer_id":43405154123866,"sku":"BWCS-AU8200SL-3","price":28.99,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-AU8200SL-big.webp?v=1779370297","url":"https:\/\/batteryweb.com\/products\/hyundai-ts21b-replacement-battery-37v-1000mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}