{"product_id":"bose-quietcomfort-20-replacement-battery-37v-240mah-li-polymer","title":"Bose QuietComfort 20 Replacement Battery 3.7V 240mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eBose QuietComfort 20 — 3.7V Li-Polymer Replacement Battery (PR-452035)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V 240mAh lithium-polymer cell replaces the original PR-452035 battery in the Bose QuietComfort 20 (QC20) in-ear headphones. It powers both the active noise cancellation circuit and audio playback. When the original cell degrades, ANC weakens or drops out entirely before the audio does — this replacement restores both functions.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eQuietComfort 20 and QC20 fit:\u003c\/strong\u003e\n    Both model names refer to the same hardware revision. They share the same battery footprint at 36.30 × 20.20 × 4.60mm, the same 3.7V nominal rail, and the same PR-452035 part number. No adapter or modification needed.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through the QC20 ANC circuit under combined noise-cancellation and audio load. The BMS held within the expected charge and discharge cutoff thresholds, and the ANC module received stable voltage throughout the draw cycle.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eANC module charging tip:\u003c\/strong\u003e\n    The QC20's noise-cancellation circuit draws current even when the headphones are not playing audio. If the battery sits discharged for weeks, charge the unit fully via the Lightning or micro-USB port before switching ANC on — powering the ANC circuit from a deeply discharged cell can cause the module to reset mid-use on the first session.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy ANC cuts out before audio does on a degraded QC20 battery\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe QC20 runs two separate draws from the same cell: the audio path and the active noise-cancellation DSP. The ANC circuit has a higher minimum operating voltage than the audio path. As the cell ages and internal resistance rises, voltage sag under combined load drops the supply below the ANC threshold first — audio keeps playing but noise cancellation shuts off. A fresh cell with lower internal resistance maintains voltage above both thresholds across the full discharge curve.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eANC indicator light stays on but noise cancellation feels weak after replacement\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens when a new cell is installed at storage voltage — typically around 3.6V — rather than after a full charge cycle. The ANC module powers on but the DSP cannot sustain full processing depth without a stable voltage above 3.7V. Charge the QC20 to 100% before the first use. If the symptom persists after a full charge, check that the battery contacts inside the housing are clean and making firm contact with the cell terminals.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43428149198938,"sku":"BWCS-BQC2SL-1","price":22.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43428149231706,"sku":"BWCS-BQC2SL-2","price":25.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43428149264474,"sku":"BWCS-BQC2SL-3","price":27.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-BQC2SL_1.webp?v=1778771731","url":"https:\/\/batteryweb.com\/products\/bose-quietcomfort-20-replacement-battery-37v-240mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}