{"product_id":"omron-cs1-replacement-battery-36v-3500mah-li-socl2","title":"Omron CS1W-BAT01 PLC Backup Battery 3.6V 3500mAh Li-SOCl2","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eOmron CS1 \/ CS1H — 3.6V Li-SOCl2 Replacement Battery (CS1W-BAT01)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.6V lithium-thionyl chloride cell rated at 3500mAh, built to replace the CS1W-BAT01 in Omron CS1 and CS1H series PLCs. It backs up SRAM program memory and the real-time clock during mains power loss. Without a live backup cell, any power interruption wipes the controller's stored program and clock data.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eCS1 and CS1H compatibility:\u003c\/strong\u003e\n    Both controller variants use the same CS1W-BAT01 footprint, voltage rail, and connector. The backup circuit draws from this single cell regardless of which CPU module is installed — no wiring changes needed between the two platforms.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell on a CS1H-CPU65H under simulated power-loss cycles. The SRAM retention circuit held steady above the 2.5V minimum threshold throughout, and the BMS showed no unexpected cutoff events during reconnection.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLive-swap procedure for CS1 controllers:\u003c\/strong\u003e\n    Always replace this battery with the PLC powered on and in RUN mode. Removing the cell while the controller is off drains SRAM instantly — the program and clock are lost the moment the cell disconnects. If a power-off swap occurred, reconnect the cell, power the PLC back on, then reload the program from your programming device.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy a fresh CS1W-BAT01 cell reads below 3.6V on the bench\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eLi-SOCl2 cells ship in a passivation state — the lithium anode develops a thin lithium chloride layer during storage that temporarily suppresses open-circuit voltage. A new cell may read as low as 3.2–3.4V on a multimeter straight out of packaging. Once installed in the PLC, the controller's float charge and low-level current draw break down the passivation layer within a few hours. At that point the cell rises to its rated 3.6V and the battery alarm clears on its own or after a manual reset.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eBattery alarm still showing after a confirmed good CS1W-BAT01 installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe CS1 series does not automatically clear a battery alarm the moment a new cell is detected — the fault flag is latched in the controller's special relay area (SR\/AR bits). After installing the new cell with the PLC powered on, open CX-Programmer, navigate to the error log, and manually clear the battery low flag. If the alarm persists after clearing, check that the cell connector is fully seated — the CS1 battery holder requires a firm click, and a half-seated connector will not complete the backup circuit. A fully cleared and connected installation should show 0 V drop across the connector pins.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43415976018010,"sku":"BWCS-OPS100SL-1","price":23.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43415976050778,"sku":"BWCS-OPS100SL-2","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43415976083546,"sku":"BWCS-OPS100SL-3","price":29.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-OPS100SL-1.webp?v=1779758775","url":"https:\/\/batteryweb.com\/products\/omron-cs1-replacement-battery-36v-3500mah-li-socl2","provider":"BatteryWeb","version":"1.0","type":"link"}