{"product_id":"funkwerk-fc4-replacement-battery-37v-700mah-li-ion","title":"Funkwerk FC4 DECT Replacement Battery 3.7V 700mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eFunkwerk FC4 \/ DECT FC4 Medical — 3.7V Li-ion Replacement Battery (5010808000)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V, 700mAh lithium-ion battery for the Funkwerk FC4 and DECT FC4 Medical cordless handsets. It replaces OEM part numbers 5010808000 and 5010808030. When the original cell degrades and talk time drops, this swap restores the handset to full operation without touching the base station or pairing setup.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eFC4 and FC4 Medical platform:\u003c\/strong\u003e\n    Both the standard FC4 and the DECT FC4 Medical share the same handset chassis, battery compartment dimensions, and connector pinout — one cell fits the full range. The Medical variant draws the same standby and transmit current as the consumer unit, so there is no electrical difference in the battery requirement.\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 the FC4 platform and monitored BMS behaviour across the full voltage window. The protection circuit tripped correctly at the low-voltage threshold and accepted charge without fault at the base station contacts.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFirst charge after installation:\u003c\/strong\u003e\n    Seat the handset in the FC4 base immediately after fitting and leave it for a full charge cycle before first use. Li-ion cells shipped in partial state of charge need one complete controlled charge to let the BMS calibrate its capacity tracking correctly.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the FC4 handset loses range shortly after a battery swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eDECT transmitters pull a short burst of higher current each time the handset communicates with the base. If the replacement cell is at low state of charge from storage, its internal resistance causes voltage to sag under that RF burst load. The base station interprets weak or broken signal as range loss — but the handset has not moved. A full charge cycle before use eliminates this behaviour because the cell can sustain voltage under the transmit pulse.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eHandset not pairing with the base after battery replacement\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eRemoving the battery from a DECT handset cuts all power to the pairing memory on some FC4 firmware versions. The handset powers back up without a stored link and sits in an unregistered state. To fix this, hold the handset's paging or find button while it is seated in the base — this re-initiates the DECT registration handshake. Once the base confirms registration, normal operation resumes.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43339897897050,"sku":"BWCS-AYD420CL-1","price":23.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43339897929818,"sku":"BWCS-AYD420CL-2","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43339897962586,"sku":"BWCS-AYD420CL-3","price":29.99,"currency_code":"USD","in_stock":true}],"url":"https:\/\/batteryweb.com\/products\/funkwerk-fc4-replacement-battery-37v-700mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}