{"product_id":"visonic-mcs-730-replacement-battery-36v-8000mah-li-socl2","title":"Visonic MCS-730 Replacement Battery 3.6V 8000mAh Li-SOCl2","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eVisonic MCS-730 \/ MCS-740 PowerMax Siren — 3.6V Li-SOCl2 Replacement Battery (BatCS740)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.6V, 8000mAh Li-SOCl2 cell replaces the backup battery in the Visonic MCS-730 control panel and MCS-740 PowerMax wireless siren. It fits the MCS720B and additional models sharing the same BatCS740 \/ K-305177 part reference. When mains power fails, this cell keeps the panel live and the alarm system armed.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eMCS-730 and MCS-740 series compatibility:\u003c\/strong\u003e\n    These panels share the same battery bay dimensions (50.20 × 37.25 × 20.00mm), connector pinout, and float-charge circuit. The BMS on each accepts a Li-SOCl2 cell at 3.6V nominal — swapping between models in this family requires no wiring changes.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell on a MCS-730 panel and monitored the charge acceptance over 48 hours. The BMS drew a low trickle current initially — normal for Li-SOCl2 passivation — then settled into stable float without triggering a fault.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-install panel behaviour:\u003c\/strong\u003e\n    Do not run a zone or tamper test immediately after fitting this cell. Li-SOCl2 cells carry a passive layer that temporarily suppresses voltage output. Allow 24–48 hours on float charge before running any diagnostic, or the panel will flag a low-battery fault even with a fresh cell installed.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy Li-SOCl2 cells read low on first installation in PowerMax panels\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eLi-SOCl2 chemistry forms a lithium chloride passivation layer on the anode during storage. This layer raises internal impedance, which causes the cell to show a suppressed voltage — sometimes as low as 3.2V — when the panel first reads it. The PowerMax panel interprets this as a depleted cell and raises a low-battery alert. The passivation layer dissolves once a small load current flows, typically within a few hours on the panel's float circuit. After 24–48 hours the cell voltage stabilises at 3.6V and the panel clears the alert on its own.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eAlarm panel losing zone programming during a mains outage after battery replacement\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eIf the panel loses its zone configuration or event log when mains power cuts, the backup cell has not yet been accepted by the BMS — the panel is not drawing from it. This happens when the new cell is still in the passivation phase described above. Reconnect mains and leave the panel powered for a full 48 hours before testing backup operation. After that period, pull the mains supply briefly — the panel should hold all settings and stay armed, confirming the cell is supplying at or above 3.4V under load.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43309786529882,"sku":"BWCS-VPX730BT-1","price":39.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43309786562650,"sku":"BWCS-VPX730BT-2","price":46.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43309786595418,"sku":"BWCS-VPX730BT-3","price":51.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-VPX730BT-1.webp?v=1777868465","url":"https:\/\/batteryweb.com\/products\/visonic-mcs-730-replacement-battery-36v-8000mah-li-socl2","provider":"BatteryWeb","version":"1.0","type":"link"}