{"product_id":"samsung-x300-replacement-battery-37v-600mah-li-ion","title":"Samsung X300 Replacement Battery 3.7V 600mAh Li-ion","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eSamsung X300 — 3.7V Li-ion Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V, 600mAh lithium-ion cell built to fit the Samsung X300 flip phone. The X300 is a compact mid-2000s handset, and original batteries at this age have typically lost 40–60% of their original capacity. This replacement restores the phone to its original operating voltage and charge cycle behaviour.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eX300 platform fit:\u003c\/strong\u003e\n    The X300 uses a single-cell 3.7V Li-ion pack with a compact footprint — 49.50 × 33.80 × 4.70mm. This cell matches that physical envelope and voltage rail exactly. No connector modification is needed.\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 X300 platform. The onboard charge IC accepted the cell without rejection, and the BMS held steady through both low-load standby and higher-draw screen-on states.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first use:\u003c\/strong\u003e\n    After fitting this cell, run one full discharge down to auto-shutdown, then charge uninterrupted to 100% before regular use. The X300's fuel gauge IC was calibrated to your old, degraded cell — it needs one complete cycle to remap its percentage readings to the new cell's actual discharge curve.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the X300 reports wrong battery percentage after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe X300 tracks charge state using a fuel gauge IC that builds a model of the cell's discharge curve over time. When you swap to a new cell, that stored model still reflects the old, degraded battery — not the fresh one. The result is percentage readings that jump around or show full charge well before the cell is actually full. One complete discharge-to-shutdown followed by a full uninterrupted charge forces the IC to relearn the curve against the new cell. After that single cycle, percentage reporting stabilises.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eSudden shutdown on the X300 with 20–30% still showing\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens when the cell voltage drops sharply under load — a behaviour called a voltage cliff. Even with charge remaining, the cell can't sustain the minimum voltage the phone's processor needs during screen-on or active use bursts. On a worn original cell this is common, but it can also occur briefly with a new cell if the fuel gauge IC hasn't recalibrated yet. Run one full discharge cycle so the IC maps the new cell's actual low-voltage threshold. If shutdowns continue after that cycle, check that the battery contacts on the phone are clean and making full contact — target at least 3.6V measured at the terminals under light load.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43409451515994,"sku":"BWCS-SMX300SL-1","price":21.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43409451548762,"sku":"BWCS-SMX300SL-2","price":24.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43409451581530,"sku":"BWCS-SMX300SL-3","price":26.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-SMX300SL-1.webp?v=1779579736","url":"https:\/\/batteryweb.com\/products\/samsung-x300-replacement-battery-37v-600mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}