{"product_id":"compaq-presario-cq42-130tu-replacement-battery-108v-6600mah-li-ion","title":"Compaq Presario CQ42 10.8V Replacement Battery HSTNN-CB0W","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eCompaq Presario CQ42-130TU Series — 10.8V Li-ion Replacement Battery (HSTNN-CB0W)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 10.8V, 6600mAh (71.28Wh) lithium-ion battery for the Compaq Presario CQ42 series, including the CQ42-130TU, CQ42-136TU, CQ42-137TU, CQ42-138TU, and over 225 additional CQ42 variants. It cross-references OEM part numbers HSTNN-CB0W, HSTNN-CB0X, HSTNN-IB0X, HSTNN-LB0W, HSTNN-Q61C, HSTNN-Q62C, 586006-321, 593554-001, and WD548AA, among others. The connector and BMS pinout match the original HP\/Compaq battery tray exactly.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eCQ42 series compatibility:\u003c\/strong\u003e\n    All CQ42 variants in this lineup share the same 10.8V three-cell-series architecture, identical connector housing, and the same BMS communication protocol over the SMBus data pin. One battery part number covers the entire platform because the charge management IC handshake does not differ between sub-models.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell on a Presario CQ42 chassis and confirmed the BMS completed a full charge cycle without triggering a protection cutoff. Capacity readout via HWMonitor settled within the expected range of the rated 71.28Wh after two full cycles.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFirst-cycle recalibration on the CQ42:\u003c\/strong\u003e\n    After installing, run one full discharge to the hibernate-cutoff threshold, then charge uninterrupted to 100%. This forces the BIOS battery learn cycle to reset against the new cell data and clears the inaccurate health warning that appears after every cell swap on CQ42 hardware.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eBIOS reporting battery health as poor after a CQ42 cell swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe CQ42 BIOS reads health status from EEPROM data written to the battery's fuel gauge IC — not from live voltage. When a new cell arrives, that EEPROM carries factory-default values the BIOS has never seen before, so it flags the battery as unknown or degraded. Running one complete discharge-to-hibernate followed by an uninterrupted full charge gives the fuel gauge IC enough data to write accurate cycle and capacity values. After that cycle completes, the health status in BIOS and Windows Battery Report corrects itself without any firmware intervention.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eCQ42 shutting down at 20–30% state-of-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 uses the old cell's discharge profile to estimate remaining charge, so it reports 25% while the real cell voltage has already dropped below the minimum load threshold under combined CPU and display draw. The laptop hits the hardware undervoltage cutoff and shuts down before the OS fuel gauge reaches zero. Run two full discharge-to-hibernate and recharge cycles — by the second cycle the IC recalculates the curve and the shutdown point should shift below 5% remaining.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43410741100634,"sku":"BWCS-HDM4HB-1","price":115.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43410741133402,"sku":"BWCS-HDM4HB-2","price":131.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43410741166170,"sku":"BWCS-HDM4HB-3","price":145.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-HDM4HB-1.webp?v=1779581113","url":"https:\/\/batteryweb.com\/products\/compaq-presario-cq42-130tu-replacement-battery-108v-6600mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}