{"product_id":"audiovox-cdm-8400-replacement-battery-37v-850mah-li-ion","title":"AudioVox BTR-8400 Replacement Battery 3.7V 850mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eAudioVox CDM-8400 Series — 3.7V Li-ion Replacement Battery (BTR-8400)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V, 850mAh Li-ion replacement battery for the AudioVox CDM-8400 mobile phone. It fits the CDM-8400, CDM-8410, CDM-8425, CDM-8455, and three additional CDM-series handsets sharing the same BTR-8400 form factor. Swap it when the original cell no longer holds a charge or the phone refuses to power on.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eCDM-8400 series compatibility:\u003c\/strong\u003e\n    These handsets share the same physical battery bay, connector pinout, and 3.7V nominal rail. The BTR-8400 part number covers all variants without modification.\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 CDM-series hardware. The BMS accepted standard charge current without interruption and held voltage within spec across the full discharge curve.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first use:\u003c\/strong\u003e\n    On first use after installation, run one full discharge to auto-off before recharging to 100%. The fuel gauge IC on these handsets calibrates its coulomb counter against the cell's actual discharge curve — skipping this step causes erratic percentage readings in the first several days of 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 CDM-8400 after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe CDM-8400's fuel gauge IC maps remaining capacity against a discharge curve learned from the original cell. A new cell with a different internal impedance profile hits a voltage cliff at a different state of charge. The handset's low-voltage cutoff triggers before the percentage display reaches zero. One full discharge-charge cycle lets the coulomb counter relearn the new cell's curve and pushes the cutoff back to the correct threshold.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003ePhone won't power on after the replacement battery sat in storage\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eLi-ion cells self-discharge during storage, and the BTR-8400 can drop below 2.5V per cell if left unused for several months. Below that threshold, the BMS enters lockout mode and blocks current flow to protect the cell from damage. Connect the phone to a charger and leave it for 20–30 minutes without attempting to power it on — the charge IC trickle-charges the cell back above the BMS recovery threshold, typically around 2.9V, before normal charging resumes.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43405155598426,"sku":"BWCS-AU8400SL-1","price":23.99,"currency_code":"USD","in_stock":false},{"title":"Warranty 2 Year","offer_id":43405155631194,"sku":"BWCS-AU8400SL-2","price":26.99,"currency_code":"USD","in_stock":false},{"title":"Warranty 3 Year","offer_id":43405155663962,"sku":"BWCS-AU8400SL-3","price":28.99,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-AU8400SL-big.webp?v=1779370314","url":"https:\/\/batteryweb.com\/products\/audiovox-cdm-8400-replacement-battery-37v-850mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}