{"product_id":"bigblue-cb9000p-replacement-battery-148v-5000mah-li-ion","title":"Bigblue CB9000P Replacement Battery 14.8V 5000mAh Li-ion","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eBigblue CB9000P Series — 14.8V Li-ion Replacement Battery (BATCELL21700X4)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 14.8V, 5000mAh lithium-ion battery pack for the Bigblue CB9000P, CB10000PRC, CB 9000P, and CB 10000P diving flashlights. It uses four 21700 cells in a series configuration. It replaces depleted or degraded packs that cause reduced output or premature shutoff underwater.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eCB9000P and CB10000P series compatibility:\u003c\/strong\u003e\n    These models share the same four-cell 21700 pack format, 14.8V nominal voltage rail, and the same connector and BMS handshake — so one part number covers the full lineup.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this pack through full charge and discharge cycles on the CB9000P driver board. The BMS held cell balance across all four 21700s and tripped protection correctly at the low-voltage cutoff threshold.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eMulti-cell replacement rule:\u003c\/strong\u003e\n    Replace all four cells at the same time from the same batch. Mixing a new pack with partially depleted cells creates imbalance — under the high current draw of turbo mode, the weaker cell drains first and can be damaged by the resulting overcurrent through its depleted capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the CB9000P steps down brightness before the indicator reads low\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe CB9000P driver uses brownout protection to step output down before the battery actually reads empty. When pack voltage drops under sustained turbo-mode draw, the driver reduces current to the LED array to prevent a hard cutoff underwater. This happens at the cell level — even if overall pack voltage looks acceptable, one imbalanced cell can trigger the threshold early. A fresh, balanced pack eliminates early stepdown in normal dive conditions.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eTurbo mode runtime noticeably shorter than standard mode\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eTurbo mode on the CB9000P draws five to ten times more current than standard mode. That rate of draw compresses the usable capacity window significantly — the pack voltage sags faster under high current, and the driver steps down or cuts off sooner than the mAh figure alone suggests. This is not a defective battery; it is a predictable effect of high-current draw on cell voltage curves. Switch to standard or medium mode for extended dives, reserving turbo for short bursts where full output is needed.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43377467228250,"sku":"BWCS-FLH271FT-1","price":67.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43377467261018,"sku":"BWCS-FLH271FT-2","price":79.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43377467293786,"sku":"BWCS-FLH271FT-3","price":88.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-FLH271FT-1.webp?v=1778767154","url":"https:\/\/batteryweb.com\/products\/bigblue-cb9000p-replacement-battery-148v-5000mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}