{"product_id":"ieasun-a9s-replacement-battery-74v-3350mah-li-ion","title":"IEASUN A9S Cable Modem Compatible Battery 7.4V 3350mAh Z2000","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eIEASUN A9S — 7.4V Li-ion Replacement Battery (Z2000)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 7.4V, 3350mAh Li-ion replacement battery for the IEASUN A9S cable modem. It fits the OEM part number Z2000 and restores the modem's battery backup function when the original cell has degraded. The A9S uses this battery to keep the modem running during AC power outages, preserving both data and VoIP connections.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eA9S backup power rail:\u003c\/strong\u003e\n    The A9S routes battery power through a dedicated backup circuit that activates the moment AC drops. The modem's firmware monitors cell voltage continuously and won't engage the backup path until the battery registers above its minimum acceptance threshold — typically around 7.0V on this platform.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through full charge and discharge on the A9S platform. The BMS handshake completed without errors, and the modem firmware accepted the new cell within one full charge cycle. No forced resets were required.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFirst-install charge cycle on the A9S:\u003c\/strong\u003e\n    After fitting this battery, leave the modem plugged into AC power for at least four hours before testing backup mode. The A9S firmware will not commit the battery to emergency standby until it has completed one supervised charge cycle and verified cell capacity internally.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the A9S battery self-test fails immediately after a swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe A9S runs an automated battery self-test at fixed intervals set by the modem firmware. If the test runs before the new cell is fully charged, the firmware logs a failure — not because the battery is faulty, but because the cell voltage hasn't reached the acceptance threshold. This is a timing issue, not a hardware fault. Allow a full four-hour charge before the next scheduled self-test fires, and the modem should log a pass result on its own.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eModem showing a battery error light after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eA steady or blinking battery indicator on the A9S after a replacement install is normal for the first 24 hours. The firmware requires time to verify the new cell's charge state, internal resistance, and capacity before clearing the error flag. No manual reset is needed in most cases — keep the modem on AC power and the indicator will clear once the firmware completes its verification sequence. If the error persists past 24 hours with a full charge, pull the battery, wait 30 seconds, and reseat it to force a fresh BMS handshake.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43333516263514,"sku":"BWCS-YMP110XL-1","price":50.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43333516296282,"sku":"BWCS-YMP110XL-2","price":59.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43333516329050,"sku":"BWCS-YMP110XL-3","price":66.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-YMP110XL-1.webp?v=1778212957","url":"https:\/\/batteryweb.com\/products\/ieasun-a9s-replacement-battery-74v-3350mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}