{"product_id":"legrand-ura-one-6-616-40-replacement-battery-48v-2000mah-ni-cd","title":"Legrand 660971 Emergency Light Compatible Battery 4.8V 2000mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eLegrand URA ONE 6 616 40 — 4.8V Ni-CD Replacement Battery (660971)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 4.8V 2000mAh Ni-CD replacement battery for Legrand emergency lighting units, cross-referenced under part numbers 660971, 9342824, and HB00040TA. It fits the URA ONE 6 616 40, URA ONE 6 626 34\/40, U21LED 6 616 10, and U21LED 6 626 07\/10 series fittings. The battery provides backup power to maintain emergency exit illumination when mains supply fails.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eURA ONE and U21LED series compatibility:\u003c\/strong\u003e\n    These fittings share the same 4.8V charge rail, physical cell pack dimensions (171 x 25 x 22.5mm), and connector pinout — which is why one battery covers both the URA ONE and U21LED ranges despite the different fascia designations.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell pack through charge and load cycles on a URA ONE fitting. The charge controller accepted the cell voltage without fault and the BMS handed off cleanly to the load circuit during simulated mains failure.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFirst test cycle after installation:\u003c\/strong\u003e\n    Within 24 hours of fitting, hold the test button for the full rated duration. Ni-CD cells from storage need one complete discharge-under-load cycle before the charge controller can accurately register capacity — skipping this step risks a false failure at your next compliance test.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the URA ONE fails its duration test even with a new battery fitted\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eNi-CD cells ship in a partially discharged state after months in a warehouse. When the fitting first charges them, it reaches float voltage quickly — but that surface charge does not reflect true cell capacity. The charge controller on these fittings uses voltage thresholds, not cycle history, to assess readiness. A cell that looks charged at float can still collapse under the emergency lighting load within minutes during a duration test. One full manual test cycle resets this and lets the cell reach its rated 2000mAh working capacity.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eCharge indicator staying red after a confirmed correct installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eSome URA ONE and U21LED fittings latch a fault condition in the charge controller firmware when the original battery voltage drops below approximately 3.6V before removal. Fitting a new cell does not automatically clear this flag. Disconnect mains power to the fitting for 30 seconds, then reconnect — this forces a charge controller reset and allows it to re-evaluate the new cell voltage. If the red LED persists after reset, measure the incoming mains supply at the terminal block and confirm it is within the 230V ±10% operating range the fitting requires to run the charge circuit.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43360412794970,"sku":"BWCS-GRU660LS-1","price":37.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43360412827738,"sku":"BWCS-GRU660LS-2","price":43.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43360412860506,"sku":"BWCS-GRU660LS-3","price":47.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-GRU660LS-1.webp?v=1778614597","url":"https:\/\/batteryweb.com\/products\/legrand-ura-one-6-616-40-replacement-battery-48v-2000mah-ni-cd","provider":"BatteryWeb","version":"1.0","type":"link"}