{"product_id":"lg-kw730-replacement-battery-37v-1500mah-li-ion","title":"LG KW730 Replacement Battery 3.7V 1500mAh BF-45FN","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eLG KW730 — 3.7V Li-ion Replacement Battery (BF-45FN)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V, 1500mAh Li-ion replacement battery for the LG KW730 smartphone. It uses OEM part number BF-45FN and slots directly into the KW730 battery bay. Capacity is rated at 5.55Wh, matching the original cell specification.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eKW730 battery bay fit:\u003c\/strong\u003e\n    The KW730 uses a removable Li-ion pack with a three-contact connector carrying positive, negative, and a BMS data line. The BF-45FN replicates this contact layout and communicates cell status back to the phone's charge IC — the phone recognises the pack and begins charging without error flags.\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 a KW730 unit. The BMS held the charge cutoff at 4.2V and the low-voltage cutoff triggered correctly before the cell voltage dropped below 3.0V. No false charge-complete signals were observed.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFirst-cycle fuel gauge reset:\u003c\/strong\u003e\n    On first use, disable fast charging if your KW730 supports it, then run one complete discharge-to-charge cycle. The fuel gauge IC on the KW730 was calibrated to the original cell's discharge curve. One full cycle lets it recalibrate against the new cell before normal use.\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 KW730 after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens because the fuel gauge IC is still using the discharge curve from the old, degraded cell. A fresh cell holds a higher voltage at any given state-of-charge, so the IC misreads remaining capacity. Under modem or screen load, the phone draws enough current to cause a brief voltage sag — the IC interprets this as a critical low-voltage event and shuts down. One full discharge cycle to around 3.4V under normal use, followed by a full charge, resets the coulomb counter to the new cell's actual curve.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eKW730 not powering on after the replacement battery sat in storage\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eLi-ion cells self-discharge during storage. If the BF-45FN cell drops below 2.5V, the BMS trips its deep-discharge lockout and the phone will not respond to a normal power-on press. Connect the phone to a charger and leave it for 15–20 minutes without attempting to power it on — the charge IC needs to trickle current into the cell at a low rate before the BMS re-enables the output circuit. Once the cell recovers to approximately 3.0V, the phone will power on normally.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43405085081690,"sku":"BWCS-LKW730SL-1","price":23.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43405085114458,"sku":"BWCS-LKW730SL-2","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43405085147226,"sku":"BWCS-LKW730SL-3","price":28.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-LKW730SL-1.webp?v=1779369919","url":"https:\/\/batteryweb.com\/products\/lg-kw730-replacement-battery-37v-1500mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}