{"product_id":"hw-391-20a-2s-balanced-bms-7-4v-8-4v-lithium-battery-protection-board","title":"HW-391 20A 2S Balanced BMS 7.4V 8.4V Lithium Battery Protection Board","description":"\u003ch2 data-pm-slice=\"1 1 []\"\u003e\u003cspan\u003eHW-391 20A 2S Balanced Lithium Battery Protection Board\u003c\/span\u003e\u003c\/h2\u003e\n\u003cp\u003e\u003cspan\u003eThe \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eHW-391 20A 2S Balanced BMS\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e is a battery protection board designed for two-cell-series lithium battery packs. It is listed for 7.4V nominal lithium-ion battery applications and includes a cell-balancing function.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThis board is identified as the \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003ebalanced version\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e of the HW-391 battery protection board. Matching product listings describe protection against overcharge, over-discharge, over-current, and short-circuit conditions.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe HW-391 is listed for lithium batteries with a nominal cell voltage of 3.7V and a full-charge voltage of 4.2V per cell, including 18650, 26650, and polymer lithium batteries.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003eKey Features\u003c\/span\u003e\u003c\/h3\u003e\n\u003cul data-spread=\"false\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003e2S battery configuration:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Designed for two cells connected in series.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003e7.4V nominal battery pack:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e For 2S lithium-ion battery applications.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003e8.4V full-charge pack voltage:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Based on two 4.2V lithium-ion cells in series.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003e20A maximum continuous discharge current:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e As listed for the HW-391.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003e10A maximum continuous charging current:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e As listed for the HW-391.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eCell balancing:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Balanced version is identified as supporting equalization charging.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eOvercharge protection:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Listed in matching HW-391 descriptions.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eOver-discharge protection:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Listed in matching HW-391 descriptions.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eOver-current protection:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Listed in matching HW-391 descriptions.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eShort-circuit protection:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Listed in matching HW-391 descriptions.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eCompact PCB:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Listed dimensions are 48 × 20 × 4mm.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch1\u003e\u003cspan\u003eTechnical Specifications\u003c\/span\u003e\u003c\/h1\u003e\n\u003ctable\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth\u003e\u003cspan\u003eSpecification\u003c\/span\u003e\u003c\/th\u003e\n\u003cth\u003e\u003cspan\u003eProduct Listing Data\u003c\/span\u003e\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eModel\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003eHW-391\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eProduct type\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e2S lithium battery BMS \/ protection board\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eVersion\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003eBalanced\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eCell configuration\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e2S (2 cells in series)\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eNominal battery voltage\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e7.4V\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eFull-charge pack voltage\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e8.4V\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eCharging voltage listed by seller\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003eDC 8.4–9V\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eContinuous discharge current\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003eMaximum 20A\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eContinuous charging current\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003eMaximum 10A\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eStarting current\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e25A, listed for drill applications\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eCompatible battery types\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e18650, 26650, polymer lithium\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eCell nominal voltage\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e3.7V\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eCell full-charge voltage\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e4.2V\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eProtection functions\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003eOvercharge, over-discharge, over-current, short-circuit\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eBalancing\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003eListed as balanced \/ equalization charging version\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eDimensions\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e48 × 20 × 4mm\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003eWeight\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e3g, as listed by Digilog\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eCharging-voltage clarification:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e The seller lists a charging input range of DC 8.4–9V. The battery pack itself is a 2S lithium-ion pack with 7.4V nominal and 8.4V at full charge. Use a suitable 2S lithium-ion charger and follow the supplier's confirmed wiring and charging instructions. The board should not be treated as a standalone charger.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch1\u003e\u003cspan\u003e Protection and Balancing Functions\u003c\/span\u003e\u003c\/h1\u003e\n\u003ch3\u003e\u003cspan\u003eCell balancing\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cspan\u003eThe HW-391 is specifically identified as the balanced version. Matching product descriptions explain that the balancing function equalizes charging between the two series cells.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003eBattery protection\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cspan\u003eMatching HW-391 listings identify these protection functions:\u003c\/span\u003e\u003c\/p\u003e\n\u003cul data-spread=\"false\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eOvercharge protection\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eOver-discharge protection\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eOver-current protection\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eShort-circuit protection\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan\u003eExact protection thresholds are not included in this listing because the sources do not consistently establish them for the exact board revision.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch1\u003e\u003cspan\u003eTypical Applications\u003c\/span\u003e\u003c\/h1\u003e\n\u003cp\u003e\u003cspan\u003ePotential applications for a properly matched HW-391 battery pack include:\u003c\/span\u003e\u003c\/p\u003e\n\u003cul data-spread=\"false\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003e2S 18650 lithium-ion battery packs\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003e2S 26650 lithium battery packs\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eCompatible lithium-polymer battery packs\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBattery-powered DIY electronics\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eSuitable power-tool battery projects\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eBattery pack protection and balancing projects\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan\u003eApplication note:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e The seller mentions power drills below 50W and resistive loads up to 168W. These are seller-listed application claims, not universal guarantees. Actual suitability depends on battery-cell capability, wiring, cooling, and the load's startup current.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch1\u003e\u003cspan\u003eInstallation Caution\u003c\/span\u003e\u003c\/h1\u003e\n\u003cul data-spread=\"false\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eUse only a compatible 2S lithium battery pack.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eConfirm the correct battery chemistry and cell voltage.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eConnect the two cells in series according to the supplier's wiring diagram.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eVerify all battery and output terminals before powering the circuit.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eDo not exceed the listed maximum charging or discharging current.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eReduce load current if the board's heat dissipation is inadequate.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eUse cells capable of supporting the required current.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eDo not confuse the BMS with a battery charger.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eConfirm wiring and polarity before connecting the load.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003ch1\u003e\u003cspan\u003e Related Products – Electronics Hub\u003c\/span\u003e\u003c\/h1\u003e\n\u003cp\u003e\u003cspan\u003eExplore related battery products:\u003c\/span\u003e\u003c\/p\u003e\n\u003cul data-spread=\"false\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003ca href=\"https:\/\/electronicshub.pk\/product\/18650-lithiom-ion-cell-in-pakistan\/\"\u003e\u003cspan\u003e18650 Lithium-Ion Cell\u003c\/span\u003e\u003c\/a\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003ca href=\"https:\/\/electronicshub.pk\/products\/1000mah-3-7v-18650-lithium-ion-cell-li-ion-battery\"\u003e\u003cspan\u003e1000mAh 3.7V 18650 Lithium-Ion Cell\u003c\/span\u003e\u003c\/a\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003ca href=\"https:\/\/electronicshub.pk\/collections\/battery-cells\/products\/3-7v-18650-battery-with-wire-jst-connector-and-bms-protection\"\u003e\u003cspan\u003e3.7V 18650 Battery with Wire, JST Connector and BMS Protection\u003c\/span\u003e\u003c\/a\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003ca href=\"https:\/\/electronicshub.pk\/collections\/battery-cells\"\u003e\u003cspan\u003eBattery Cells Collection\u003c\/span\u003e\u003c\/a\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cem\u003e\u003cspan\u003eThese are related products. Confirm cell current capability, pack configuration, and wiring compatibility before pairing them with the HW-391.\u003c\/span\u003e\u003c\/em\u003e\u003c\/p\u003e","brand":"Electronics Hub","offers":[{"title":"Default Title","offer_id":67874739487033,"sku":null,"price":245.0,"currency_code":"PKR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0965\/3623\/2249\/files\/01_main_product_image_ba05b4ef-fadc-4110-a158-87cf21d531ca.jpg?v=1793292778","url":"https:\/\/electronicshub.pk\/products\/hw-391-20a-2s-balanced-bms-7-4v-8-4v-lithium-battery-protection-board","provider":"Electronics Hub","version":"1.0","type":"link"}