{"product_id":"mitsubish-a1fxcpu-replacement-battery-36v-1700mah-li-socl2","title":"Mitsubishi A1FXCPU PLC Replacement Battery 3.6V 1700mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eMitsubish A1FXCPU \/ AnS Series — 3.6V Li-SOCl2 Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.6V, 1700mAh lithium-thionyl chloride cell replaces the backup battery in Mitsubishi A-series PLCs including the A1FXCPU, A1S, A2S, and AnS families. Its job is SRAM retention and real-time clock maintenance when mains power drops. Without it, a power interruption wipes the program and resets the clock.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eA-series platform fit:\u003c\/strong\u003e\n    The A1FXCPU, A1S, A2S, and AnS controllers share the same battery compartment format and 3.6V supply rail for their SRAM backup circuit. A single cell type covers the range because the memory retention voltage threshold is identical across these CPU modules.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell on an A-series CPU and confirmed the BMS handshake — the battery alarm cleared immediately on insertion with the controller live, and SRAM held program data through a simulated mains drop.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eHot-swap procedure on A-series CPUs:\u003c\/strong\u003e\n    Always replace this battery with the PLC powered on and in RUN mode. Removing the old cell while the controller is de-energised cuts the SRAM supply instantly — the program and retentive data are gone before the new cell seats. Keep power on for the entire swap.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the A1FXCPU loses its program after a battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe A1FXCPU holds its ladder logic and retentive data in SRAM, not flash. SRAM needs continuous voltage — the moment the battery is pulled with the PLC off, that voltage collapses to zero and every memory address clears. Even a two-second gap during cell changeover is enough. The battery compartment on these modules is not designed for capacitor-backed bridging, so there is no tolerance window. Swap only with the controller powered and in RUN mode.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eBattery alarm not clearing after a confirmed good installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eFitting a new cell does not automatically reset the battery alarm flag on A-series CPUs — the fault latch stays set in the controller's diagnostic register until it is cleared manually. Connect GX Developer or GX Works to the CPU, navigate to the diagnostics screen, and clear the battery error bit from there. The alarm will persist on the programming console and any SCADA display until that step is done. A fresh cell reading 3.6V in circuit confirms the hardware side is correct — the remaining task is purely a software reset.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43415988207706,"sku":"BWCS-MMR967SL-1","price":22.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43415988240474,"sku":"BWCS-MMR967SL-2","price":25.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43415988273242,"sku":"BWCS-MMR967SL-3","price":27.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-MMR967SL-1.webp?v=1779758841","url":"https:\/\/batteryweb.com\/products\/mitsubish-a1fxcpu-replacement-battery-36v-1700mah-li-socl2","provider":"BatteryWeb","version":"1.0","type":"link"}