{"product_id":"vodafone-845-replacement-battery-37v-1300mah-li-ion","title":"Vodafone HB4J1 Compatible Battery 3.7V 1300mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eVodafone 845 \/ 858 Series — 3.7V Li-ion Replacement Battery (HB4J1)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V, 1300mAh Li-ion cell replaces the HB4J1 and HB4J1H batteries used in the Vodafone 845, 858, 858 Smart, and V858 smartphones. It matches the original voltage rail and physical footprint exactly — 54 x 43 x 5mm. Swap it in when the original cell no longer holds a charge through a normal day.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003e845 and 858 platform compatibility:\u003c\/strong\u003e\n    These models share the same battery bay dimensions, connector pinout, and 3.7V nominal voltage rail. The HB4J1 and HB4J1H part numbers are interchangeable across this group — same BMS handshake, same charge IC communication.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through charge and discharge on the 845 platform. The BMS accepted the cell without fault flags, charge IC negotiated correctly, and the fuel gauge IC began tracking state-of-charge within the first full cycle.\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\"\u003eWhy the Vodafone 845 reports wrong battery percentage after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe 845 uses a fuel gauge IC that builds its state-of-charge model from the discharge curve of the cell it was calibrated against — your original, degraded battery. A new cell has a different internal resistance and a steeper voltage curve at low charge. The gauge reads that curve incorrectly and reports percentages that don't match actual capacity. One full discharge down to automatic shutdown, followed by a full uninterrupted charge, resets the coulomb counter and aligns the IC to the new cell's behaviour.\u003c\/p\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 when the modem or display draws a short high-current burst and the cell voltage dips below the BMS cutoff threshold — even though the gauge still shows charge remaining. It is a calibration gap, not a faulty battery. The fuel gauge IC is mapping the new cell's voltage against the old cell's stored curve, so the reported percentage is ahead of reality. Run one full cycle without interruption and the shutdowns will stop once the IC locks onto the correct voltage cliff point near 3.2V.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43404341870682,"sku":"BWCS-HU8160XL-1","price":23.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43404341903450,"sku":"BWCS-HU8160XL-2","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43404341936218,"sku":"BWCS-HU8160XL-3","price":28.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-HU8160XL-1.webp?v=1779369761","url":"https:\/\/batteryweb.com\/products\/vodafone-845-replacement-battery-37v-1300mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}