{"product_id":"compaq-presario-cq42-130tu-replacement-battery-108v-4400mah-li-ion","title":"HSTNN-CB0W Compatible Battery for Compaq Presario CQ42 10.8V 4400mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eCompaq Presario CQ42 Series — 10.8V Li-ion Replacement Battery (HSTNN-CB0W)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 10.8V, 4400mAh (47.52Wh) lithium-ion battery for the Compaq Presario CQ42 series laptops, including the CQ42-130TU, CQ42-136TU, CQ42-137TU, and CQ42-138TU among 225+ compatible models. It replaces OEM part numbers HSTNN-CB0W, HSTNN-CB0X, HSTNN-IB0X, HSTNN-LB0W, and others listed above. Install it when the original cell no longer holds a charge or fails to power the notebook off mains.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eCQ42 platform compatibility:\u003c\/strong\u003e\n    These CQ42 models share the same 10.8V three-cell architecture, connector pinout, and BMS handshake protocol — that is why one cell pack covers so many SKUs across the Presario line.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell on a CQ42 unit and confirmed the BMS completed full charge handshake, protection thresholds triggered correctly at low-voltage cutoff, and the pack communicated accurate data over the SMBus interface.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-install discharge cycle on the CQ42:\u003c\/strong\u003e\n    After fitting this battery, run one full discharge to hibernate-cutoff, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears on the first boot after a cell 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 CQ42 BIOS reports poor battery health straight after a new cell install\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe CQ42's BIOS stores learned capacity data from the old cell in firmware. When a new cell goes in, that stored data no longer matches the actual chemistry — the BIOS flags poor health immediately. This is not a fault with the replacement pack. One full discharge-to-hibernate followed by an uninterrupted charge to 100% forces the BIOS to re-run its learn cycle and write fresh capacity figures. After two to three cycles the health status normalises.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eCQ42 shutting down at 20–30% charge shown on screen\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens when the fuel gauge IC has not yet calibrated against the new cell's actual voltage curve. The IC still references the old cell's data, so it misreads the remaining capacity and triggers a shutdown well before the cell is truly empty. It is not a hardware fault. Run two full discharge-to-hibernate cycles followed by full uninterrupted charges — after that the gauge IC locks onto the correct curve and the early shutdown stops. If it persists after three cycles, check that the BIOS is not also applying a charge limit, which will artificially flatten the top end of the voltage curve down to around 8.1V per cell.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43411617415258,"sku":"BWCS-HDM4NB-1","price":37.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43411617448026,"sku":"BWCS-HDM4NB-2","price":42.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43411617480794,"sku":"BWCS-HDM4NB-3","price":46.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-HDM4NB-1.webp?v=1779581142","url":"https:\/\/batteryweb.com\/products\/compaq-presario-cq42-130tu-replacement-battery-108v-4400mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}