{"product_id":"technics-eah-f70n-replacement-battery-37v-700mah-li-polymer","title":"Technics EAH-F70N Replacement Battery 3.7V 700mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eTechnics EAH-F70N — 3.7V Li-Polymer Replacement Battery (FT523230P)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V, 700mAh lithium-polymer cell replaces the original FT523230P battery inside the Technics EAH-F70N wireless noise-cancelling headphones. It restores full wireless audio and active noise cancellation when the original cell has degraded. Dimensions are 35.00 × 29.60 × 6.70mm — confirm against your existing cell before fitting.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eEAH-F70N fit notes:\u003c\/strong\u003e\n    The EAH-F70N runs its Bluetooth radio, DSP, and active noise-cancellation circuit from a single 3.7V cell. All three draw simultaneously during use, so the replacement cell must match the original's footprint and voltage tolerance exactly — any deviation trips the headphone's internal protection circuit.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell under combined ANC and Bluetooth load and confirmed the BMS accepted the pack without throwing a protection fault. Charge acceptance was normal across the full CV\/CC cycle.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFirst-cycle charging on the EAH-F70N:\u003c\/strong\u003e\n    After fitting, charge the headphones to 100% before using ANC. The headphone firmware recalibrates its battery gauge on the first full charge cycle — skipping this gives an inaccurate charge indicator for the first several uses.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the EAH-F70N cuts out mid-track with a new battery fitted\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe EAH-F70N draws from the cell on three rails at once: Bluetooth, the DSP audio processor, and the ANC feedback loop. Under that combined load, a cell that hasn't completed its first full charge cycle can sag below the BMS cutoff threshold — typically around 3.0V — causing the headphones to shut off without warning. This isn't a faulty cell; it's the protection circuit doing its job on an under-conditioned pack. Run two or three full charge-discharge cycles and the cell's internal resistance drops, reducing voltage sag under peak load.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eHeadphones show full charge but go silent after a few tracks\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eA replacement cell shipped at storage voltage (roughly 3.6–3.8V) can fool the EAH-F70N's fuel gauge into reporting a full charge before the cell has actually been topped up. The firmware reads voltage, not true state of charge, until it completes a calibration cycle. Place the headphones on charge until the indicator shows 100%, then let them discharge fully once — this forces a gauge reset. After that cycle, the charge readout will track accurately.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43428097097818,"sku":"BWCS-PLF200SL-1","price":30.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43428097130586,"sku":"BWCS-PLF200SL-2","price":35.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43428097163354,"sku":"BWCS-PLF200SL-3","price":39.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-PLF200SL-1.webp?v=1779934086","url":"https:\/\/batteryweb.com\/products\/technics-eah-f70n-replacement-battery-37v-700mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}