{"product_id":"motorola-moto-z4-replacement-battery-385v-3350mah-li-polymer","title":"Motorola Moto Z4 KZ40 Replacement Battery 3.85V 3350mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eMotorola Moto Z4 \/ XT1980-3 — 3.85V Li-Polymer Replacement Battery (KZ40)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3350mAh Li-Polymer cell rated at 3.85V, replacing the OEM KZ40 battery in the Motorola Moto Z4 and XT1980-3 smartphones. It restores power capacity to phones where the original cell no longer holds a useful charge. Dimensions are 78.70 × 62.52 × 4.10mm — match these before ordering.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eMoto Z4 and XT1980-3 fit:\u003c\/strong\u003e\n    Both variants use the same KZ40 cell form factor, voltage rail, and connector pinout. The BMS handshake is identical across the XT1980-3 hardware revision, so one cell covers both.\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 Moto Z4 unit. The BMS accepted the cell without error flags, and fast-charge negotiation completed normally after the first full cycle.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first use:\u003c\/strong\u003e\n    After installation, disable fast charging and run one full discharge-to-charge cycle at standard current. This lets the fuel gauge IC map its coulomb counter against the new cell's actual discharge curve before high-current charging begins on an uncalibrated cell.\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 Moto Z4 after a cell swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens because the fuel gauge IC is still calibrated to the old cell's voltage curve. A new cell has a steeper voltage cliff at the lower end — the phone reads 25% but the actual cell voltage drops below the modem's sustain threshold under load. The BMS triggers a protection cutoff before the OS can react. One full discharge cycle from 100% to automatic shutdown, then a full charge, resets the coulomb counter to the new cell's curve.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eUSB-PD fast charge not working on the first cycle after replacement\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eOn the first charge after a cell swap, the charge IC may default to slow charge while it verifies the new cell's impedance. This is normal — the controller is running a trickle-phase check before enabling high-current input. Do not assume the battery is faulty. Complete one full standard-rate charge cycle, then reconnect the fast charger. Fast-charge negotiation typically resumes from the second cycle onward once the IC has confirmed cell integrity.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43391989350490,"sku":"BWCS-MXT198SL-1","price":25.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43391989383258,"sku":"BWCS-MXT198SL-2","price":28.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43391989416026,"sku":"BWCS-MXT198SL-3","price":31.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-MXT198SL-1.webp?v=1779142762","url":"https:\/\/batteryweb.com\/products\/motorola-moto-z4-replacement-battery-385v-3350mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}