{"product_id":"fujikura-fsm-80c-replacement-battery-148v-4000mah-li-ion","title":"Fujikura BTR-09 FSM-80C Replacement Battery 14.8V 4000mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eFujikura FSM-80C \/ FSM-61S \/ FSM-80S Series — 14.8V Li-ion Replacement Battery (BTR-09)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 14.8V 4000mAh (59.2Wh) Li-ion battery for Fujikura fusion splicers using the BTR-09 pack. It fits the FSM-80C, FSM-61S, FSM-62S, FSM-80S, and six additional models in the same platform family. Voltage and cell count match the original spec exactly.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eFSM-80 and FSM-61\/62 platform fit:\u003c\/strong\u003e\n    These models share the same battery bay geometry, 14.8V four-cell Li-ion architecture, and BMS communication protocol. The connector pinout and thermal sensor line are identical across the group, so the pack seats and negotiates correctly without firmware conflicts.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this pack on an FSM-80C and cycled it through arc calibration, motor drive, and heater sequences. The BMS held stable across all load transitions — no nuisance cutoffs during the electrode gap motor pulse or the splice cycle.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePre-deployment calibration on the FSM-80C:\u003c\/strong\u003e\n    After fitting this pack, run a full auto-calibration from the splicer menu before heading to site. The FSM-80C maps battery state during that calibration sequence. Skip it and the low-battery indicator fires early — sometimes mid-splice on the first field session.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eFSM-80C shutting down at arc discharge or heater activation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe FSM-80C draws a sharp current spike when the arc fires and again when the heat shrink oven activates. On a degraded or cold-soaked pack, this spike can push the BMS over its instantaneous current threshold and trigger a protective cutoff. The splicer goes dark mid-cycle — not a fault with the machine. A new pack with healthy internal resistance handles these spikes without hitting the cutoff floor. If shutdowns persist in cold conditions, warm the battery to above 10°C before use — Li-ion internal resistance rises sharply below that point.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eSplicer not recognising pack after months in the carry case\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eLi-ion cells self-discharge during storage. If a pack sits unused long enough to drop below approximately 2.5V per cell (10V total for a 4S pack), the BMS enters sleep mode and blocks charge input as a safety measure. The FSM-80C will power on briefly or show no battery detected. Connect the pack to the Fujikura charger and leave it for 15–30 minutes — most BTR-09 compatible chargers apply a low-current recovery pulse that wakes the BMS before switching to normal charge current. If the charger shows no activity after 30 minutes, the cells may be below recovery threshold.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43360633716826,"sku":"BWCS-FKR900SL-1","price":223.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43360633749594,"sku":"BWCS-FKR900SL-2","price":265.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43360633782362,"sku":"BWCS-FKR900SL-3","price":296.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-FKR900SL-1.webp?v=1778616113","url":"https:\/\/batteryweb.com\/products\/fujikura-fsm-80c-replacement-battery-148v-4000mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}