{"product_id":"att-fusion-5g-replacement-battery-387v-4600mah-li-polymer","title":"HE403 AT\u0026T Fusion 5G Replacement Battery 3.87V 4600mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eAT\u0026amp;T Fusion 5G — 3.87V Li-Polymer Replacement Battery (HE403)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.87V, 4600mAh Li-Polymer replacement battery for the AT\u0026amp;T Fusion 5G smartphone. It fits models EA211005 and EA211001 and replaces OEM part number HE403. It powers the display, processor, and wireless radios at the same voltage the phone's charge IC expects.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eFusion 5G platform fit:\u003c\/strong\u003e\n    The EA211005 and EA211001 share the same battery bay geometry, connector pin-out, and 3.87V nominal rail. The charge IC and BMS handshake protocol are identical across both variants, so one cell covers both.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell on the Fusion 5G platform and confirmed the BMS accepted charge handshake on first power-on, held voltage above the 3.4V cutoff threshold under simultaneous 5G modem and display load, and logged no protection-circuit trips during discharge.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first use:\u003c\/strong\u003e\n    On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC recalibrate against the new cell's discharge curve before high-current charging pushes current into 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 Fusion 5G after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens because the fuel gauge IC was calibrated to the old cell's discharge curve. The new cell hits a voltage cliff — it cannot sustain voltage under simultaneous modem and screen load — even though the reported percentage looks safe. The phone interprets the voltage drop as an emergency and cuts power. One full discharge-charge cycle without fast charging forces the coulomb counter to remap against the new cell and resolves this.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eUSB-PD fast charge not activating after replacement\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eOn the first cycle after a cell swap, the charge IC may not complete the USB-PD negotiation handshake with the new BMS. The phone defaults to standard 5W charging as a safety fallback. Plug the phone in, let it reach 100% on standard charge, then reboot. The charge IC re-runs BMS negotiation on the next plug-in event and fast charge resumes at rated wattage.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43391801491546,"sku":"BWCS-CKA211SL-1","price":35.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43391801524314,"sku":"BWCS-CKA211SL-2","price":41.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43391801557082,"sku":"BWCS-CKA211SL-3","price":45.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-CKA211SL-1.webp?v=1779142181","url":"https:\/\/batteryweb.com\/products\/att-fusion-5g-replacement-battery-387v-4600mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}