{"product_id":"sony-wf-1000xm3-charging-case-replacement-battery-37v-800mah-li-ion","title":"Sony WF-1000XM3 Charging Case Compatible Battery 3.7V 800mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eSony WF-1000XM3 Charging Case — 3.7V Li-ion Replacement Battery (1588-0911)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V, 800mAh Li-ion replacement for the internal battery inside the Sony WF-1000XM3 charging case. It also fits the WF-SP900 charging case. When the case battery degrades, the case stops holding enough charge to top up the earbuds away from a wall outlet — this cell restores that function.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eWF-1000XM3 and WF-SP900 case compatibility:\u003c\/strong\u003e\n    Both cases use the same 1588-0911 cell on a shared 3.7V rail with the same physical footprint and connector orientation. The BMS in each case communicates with the cell over the same two-pin logic line, so one replacement covers both.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran the cell through full charge and discharge cycles on a WF-1000XM3 case. The BMS accepted the new cell without errors, and the case delivered consistent charge passes to the earbuds across repeated cycles.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFirst charge after installation:\u003c\/strong\u003e\n    Place the case on a USB-C charger and run it to 100% before putting earbuds in. The case BMS needs one full cycle to log the new cell's capacity — skip this and the LED charge indicator may read inaccurately for the first week of use.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the WF-1000XM3 case shows full charge but the earbuds go flat anyway\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe case has no direct voltage readout — it estimates remaining capacity from the cell's state of charge curve. When the original cell ages, its voltage curve flattens and the BMS misreads remaining capacity by a wide margin. A depleted cell sitting at storage voltage will report 100% right after a short partial charge, then drop off fast under earbud load. Replacing the cell resets the curve the BMS tracks against.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eCase LED stays solid white but earbuds are not charging inside\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eA solid white LED means the case thinks it has charge available, but a severely degraded cell can hold just enough voltage to trigger the LED without sustaining the current needed to push charge into the earbuds. The earbuds draw a small but steady current when seated — if the case cell voltage sags below 3.4V under that load, the charging circuit shuts off silently. Fit the new cell and run one full USB-C charge cycle before testing earbud charging. Check that the earbuds seat correctly in the contacts before ruling out a cell issue.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43428118134874,"sku":"BWCS-SWH110SL-1","price":23.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43428118167642,"sku":"BWCS-SWH110SL-2","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43428118200410,"sku":"BWCS-SWH110SL-3","price":28.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-SWH110SL-1.webp?v=1779934190","url":"https:\/\/batteryweb.com\/products\/sony-wf-1000xm3-charging-case-replacement-battery-37v-800mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}