{"product_id":"comfortel-m-520-replacement-battery-37v-950mah-li-ion","title":"COMfortel M-520 Replacement Battery 3.7V 950mAh Li-ion","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eCOMfortel M-520 \/ M-710 — 3.7V Li-ion Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V, 950mAh Li-ion battery fits the COMfortel M-520 and M-710 cordless DECT handsets. It replaces the original cell when the handset no longer holds adequate charge between base visits. Dimensions are 52.95 × 35.10 × 4.50mm — confirm these against your existing cell before fitting.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eM-520 and M-710 compatibility:\u003c\/strong\u003e\n    Both handsets share the same battery bay dimensions, connector pinout, and 3.7V Li-ion charging circuit in the base station, so one cell covers either model.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran charge and discharge cycles through the M-520's base station circuit. The protection board handled overcharge cutoff cleanly at 4.2V and low-voltage cutoff triggered correctly before cell damage could occur.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFirst charge after fitting:\u003c\/strong\u003e\n    Place the handset in the base immediately after installing this battery and leave it for a full 16 hours before making calls. Li-ion cells shipped partially discharged — the base charging circuit needs an uninterrupted cycle to calibrate the charge state correctly.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eTalk time shorter than expected after fitting a new Li-ion cell\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eA new Li-ion cell shipped from storage often arrives at 30–50% state of charge. If you make calls before completing a full charge cycle, the handset's fuel gauge starts from an inaccurate baseline. The base station then underestimates remaining capacity on subsequent charges. One full 16-hour charge from near-empty resets this and brings talk time up to the rated figure.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eBase station charge light not activating with new battery installed\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eIf the base shows no charge indicator after fitting, the battery voltage may be low enough that the base circuit treats it as an error state rather than a chargeable cell. Remove the handset, wait 10 seconds, and reseat it firmly — poor contact at the charging pins is a common cause. If the light still does not activate, check the battery voltage with a multimeter at the contacts; a reading below 3.0V means the cell discharged deeply in storage and needs a trickle charge before the base circuit will accept it.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43339920375898,"sku":"BWCS-SX785CL-1","price":22.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43339920408666,"sku":"BWCS-SX785CL-2","price":25.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43339920441434,"sku":"BWCS-SX785CL-3","price":27.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-SX785CL-1.webp?v=1778367002","url":"https:\/\/batteryweb.com\/products\/comfortel-m-520-replacement-battery-37v-950mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}