{"product_id":"360-n4-replacement-battery-385v-3000mah-li-polymer","title":"360 N4 Replacement Battery QK-393 3.85V 3000mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003e360 N4 Series — 3.85V Li-Polymer Replacement Battery (QK-393)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.85V, 3000mAh (11.55Wh) Li-Polymer cell replacing the QK-393 battery in the 360 N4 smartphone. It fits the N4, 1503-A01, and 1503-M02 variants. The physical dimensions are 73.40 × 63.10 × 3.90mm — measure your original cell before ordering if your device has been serviced before.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eN4, 1503-A01, and 1503-M02 compatibility:\u003c\/strong\u003e\n    All three model numbers share the same battery bay geometry, connector pinout, and BMS handshake protocol — that is why one cell covers all three variants without modification.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran the QK-393 replacement through full charge and load cycles on N4 hardware. The BMS accepted charge current correctly, thermal monitoring stayed within normal range, and the protection circuit tripped as expected at low-voltage cutoff.\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-to-charge cycle. This lets the fuel gauge IC build an accurate discharge curve against the new cell before high-current charging pushes current into an uncalibrated state.\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 replacement cell\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens because the fuel gauge IC is still reading the old cell's discharge curve. A new Li-Polymer cell has a slightly different voltage-to-capacity slope. When the modem fires or the screen brightness spikes, the cell voltage dips below the threshold the gauge hasn't recalibrated for yet, and the device shuts off to protect the circuit. The fix is a full uninterrupted discharge down to automatic shutdown, followed by a full charge without interruption. After that single cycle, the coulomb counter resets against the new cell's actual curve and the shutdowns stop.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eUSB charging not recognised on the first plug-in after cell swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eAfter a cell swap, the charge IC sometimes fails to negotiate the correct charging profile on the first connection — the phone shows no charge icon or charges at a very slow rate. This occurs because the BMS on the new cell starts in a conservative low-current mode until it completes an initial handshake with the device's charge controller. Disconnect the cable, wait 30 seconds, then reconnect. If the issue persists after two reconnections, boot the phone fully before plugging in — this resets the charge IC negotiation stack and normal charging resumes.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43392078282842,"sku":"BWCS-KKL400SL-1","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43392078315610,"sku":"BWCS-KKL400SL-2","price":30.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43392078348378,"sku":"BWCS-KKL400SL-3","price":33.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-KKL400SL-1.webp?v=1779143621","url":"https:\/\/batteryweb.com\/products\/360-n4-replacement-battery-385v-3000mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}