{"product_id":"audiovox-cdm-4000-replacement-battery-37v-1050mah-li-ion","title":"AudioVox BTR-4000 Replacement Battery 3.7V 1050mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eAudioVox CDM-4000 \/ CDM-4500 \/ CDM-9000 — 3.7V Li-ion Replacement Battery (BTR-4000)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V Li-ion replacement battery rated at 1050mAh (3.89Wh) for the AudioVox CDM-4000, CDM-4500, and CDM-9000 mobile phones. It replaces OEM part number BTR-4000 and fits the original battery bay without modification. When the factory cell no longer holds a charge, this swap restores basic phone function.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eCDM-4000 \/ CDM-4500 \/ CDM-9000 compatibility:\u003c\/strong\u003e\n    All three models share the same BTR-4000 form factor, connector pinout, and 3.7V nominal voltage rail. The BMS handshake on each device recognises this cell without firmware conflict.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this battery through charge and discharge on the CDM platform. The BMS accepted the cell on first insertion, charge current ramped correctly through CC\/CV stages, and no overcurrent trips were logged.\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 if available and run one complete discharge-to-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before reporting an accurate state-of-charge reading to the OS.\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 after a cell swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis is a voltage cliff problem, not a capacity problem. Under peak modem transmit load or backlight demand, a fresh cell that hasn't been calibrated can sag below the BMS cutoff threshold even when the fuel gauge still reads 25%. The phone's protection circuit cuts power to prevent cell damage. One full discharge-charge cycle lets the coulomb counter anchor its low-voltage endpoint to the actual cell, pushing the cutoff point to a realistic level. After calibration, shutdowns below 20% should stop.\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 in storage. If a replacement cell drops below roughly 2.5V, the BMS enters lockout mode and blocks all charge current to prevent a hazardous charge into a deeply depleted cell. The phone shows nothing — no charging indicator, no boot. Connect the device to a wall charger, not a PC USB port, and leave it undisturbed for 20–30 minutes. A wall charger delivers enough current to trigger the BMS trickle-charge recovery routine; once the cell climbs above 2.9V, normal charging resumes and the phone will power on.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43405154648154,"sku":"BWCS-AU4500SL-1","price":23.99,"currency_code":"USD","in_stock":false},{"title":"Warranty 2 Year","offer_id":43405154680922,"sku":"BWCS-AU4500SL-2","price":26.99,"currency_code":"USD","in_stock":false},{"title":"Warranty 3 Year","offer_id":43405154713690,"sku":"BWCS-AU4500SL-3","price":28.99,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-AU4500SL-big.webp?v=1779370298","url":"https:\/\/batteryweb.com\/products\/audiovox-cdm-4000-replacement-battery-37v-1050mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}