{"product_id":"kazuna-etalk-4g-replacement-battery-38v-1400mah-li-polymer","title":"Kazuna eTalk 4G BP1578 Replacement Battery 3.8V 1400mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eKazuna eTalk 4G \/ KAZ-F019 — 3.8V Li-Polymer Replacement Battery (BP1578)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.8V, 1400mAh Li-Polymer cell replaces the BP1578 battery in the Kazuna eTalk 4G and KAZ-F019 series handsets. It fits the senior-focused eTalk lineup, including KAZ-F019PP and related variants. Capacity is 5.32Wh — matching OEM specification from the product data.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eeTalk 4G \/ KAZ-F019 platform fit:\u003c\/strong\u003e\n    The KAZ-F019 and KAZ-F019PP share the same battery bay dimensions and connector pinout. The BP1578 designation is consistent across these variants, so one cell covers the full eTalk 4G range without modification.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through a full discharge-charge sequence on the eTalk 4G platform and confirmed the BMS accepted charge termination correctly — no false-full cutoff and no trickle-lock at low state of charge.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first cycle:\u003c\/strong\u003e\n    On first use after installation, disable fast charging and run one complete discharge down to automatic shutdown, then charge uninterrupted to 100%. This gives the fuel gauge IC one full reference cycle against the new cell's discharge curve before it starts tracking percentage accurately.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the eTalk 4G shuts off suddenly at 20–30% after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe eTalk 4G's fuel gauge IC retains the discharge curve learned from the original degraded cell. When a new cell is installed, the IC's voltage-to-percentage mapping is out of sync. At around 20–30% displayed charge, the actual cell voltage drops below the threshold the OS expects for that percentage, triggering an emergency shutdown. This is not a cell defect — it is a coulomb counter calibration mismatch. One full uninterrupted discharge-charge cycle resets the reference curve and resolves the cutoff.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003ePhone warm near the battery during the first charge after replacement\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eA new Li-Polymer cell has higher internal impedance than a broken-in cell. On the first charge cycle, the charge IC pushes current into that higher-impedance cell, which generates more heat than normal. This typically appears during the constant-current phase of charging. It is self-limiting — impedance drops after one or two cycles and the warmth normalises. If surface temperature stays below approximately 40°C and drops after 20 minutes, no action is needed; if it continues rising, disconnect and check connector seating.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43391904612442,"sku":"BWCS-KZA157SL-1","price":25.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43391904645210,"sku":"BWCS-KZA157SL-2","price":28.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43391904677978,"sku":"BWCS-KZA157SL-3","price":31.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-KZA157SL-1.webp?v=1779142595","url":"https:\/\/batteryweb.com\/products\/kazuna-etalk-4g-replacement-battery-38v-1400mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}