{"product_id":"codio-k8-replacement-battery-38v-450mah-li-polymer","title":"Codio K8 Smartwatch Compatible Battery 3.8V 450mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eCodio K8 \/ T8 — 3.8V Li-Polymer Replacement Battery (W801)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.8V, 450mAh lithium-polymer cell for the Codio K8 and T8 smartwatches. It replaces the original W801 battery when the watch no longer holds charge across a full day of use. At 29.50 x 27.70 x 5.00mm, it matches the footprint of the factory cell.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eK8 and T8 platform fit:\u003c\/strong\u003e\n    Both models share the same chassis dimensions, connector position, and BMS handshake protocol — one cell covers both. The W801 part number is the same across the K8 and T8 production runs.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell through charge and discharge cycles on a K8 unit. The BMS accepted the new cell without fault flags, and the fuel gauge read correctly after a full charge cycle from near-zero.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge reset after swap:\u003c\/strong\u003e\n    After fitting this cell, place the watch straight on its charger and run it to 100% before first use. The fuel gauge IC on the K8 loses its reference point when the old cell is removed — skipping this step causes the watch to report incorrect percentages for days.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the K8 shows 0% immediately after a battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe K8 uses a coulomb-counting fuel gauge IC that tracks charge state relative to a stored reference. Removing the old battery wipes that reference entirely. When the new cell lands in the circuit, the IC has no baseline, so it defaults to 0% or shuts the display off. A full charge from near-zero re-anchors the IC to the new cell's actual capacity. Do not judge the new battery's condition until after that first complete charge cycle.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWatch not pairing after battery replacement\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eRemoving the battery cuts power to the BLE radio mid-session. The phone retains the old pairing record but the watch starts with a clean Bluetooth stack — the two sides no longer recognise each other. Go into your phone's Bluetooth settings, forget the K8 device entirely, then re-pair from scratch. Do not attempt to reconnect through the fitness app until the device appears as a fresh entry in your phone's Bluetooth list.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416173543514,"sku":"BWCS-COT800SH-1","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416173576282,"sku":"BWCS-COT800SH-2","price":29.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416173609050,"sku":"BWCS-COT800SH-3","price":32.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-COT800SH-1.webp?v=1779760547","url":"https:\/\/batteryweb.com\/products\/codio-k8-replacement-battery-38v-450mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}