{"product_id":"battery-voltage-internal-resistance-tester-ac-4-wire-99-groups","title":"AC 4-Wire Battery Voltage \u0026 Internal Resistance Tester | 99 Groups","description":"\n\u003ch2\u003e1.77-Inch Voltage \u0026amp; Internal Resistance Tester — AC 4-Wire Method\u003c\/h2\u003e\n\u003cp\u003eGet precise, repeatable battery measurements with this compact AC 4-Wire Method Voltage and Internal Resistance Tester. Whether you're sorting battery cells for DIY power packs, evaluating lithium or LiFePO4 batteries, or benchmarking cells for an electronics project, this handheld tester delivers high-resolution readings and intuitive grading — all in a pocket-sized package. Made in Mainland China.\u003c\/p\u003e\n\n\u003ch3\u003eKey Features\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHigh-Resolution Measurement:\u003c\/strong\u003e Voltage range 0.001 V – 60.00 V (resolution 0.001 V); internal resistance range 0.1 mΩ – 6.999 Ω (resolution 0.1 mΩ).\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAC 4-Wire Testing Method:\u003c\/strong\u003e Eliminates lead-resistance errors for more accurate internal resistance readings compared to 2-wire methods.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e99-Group Data Storage:\u003c\/strong\u003e Manually save and review up to 99 sets of voltage and internal resistance measurements directly on the device — no PC required.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e4-Grade Sorting (A \/ B \/ C \/ D):\u003c\/strong\u003e Built-in internal resistance grading and voltage reference evaluation make cell matching and quality screening quick and intuitive.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e1.77-Inch Display:\u003c\/strong\u003e Clear, bright screen with 9 levels of adjustable backlight brightness for comfortable use in any lighting condition.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAdjustable Auto Power-Off:\u003c\/strong\u003e Set standby time from 1 to 9 minutes; screen-off standby current drops below 1 mA to conserve battery.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBuilt-In 4056 Charging Module:\u003c\/strong\u003e Supports ternary lithium and LiFePO4 battery power supply and charging — power it with any standard 5 V \/ Type-C adapter.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e90% Pre-Assembled, Compact Body:\u003c\/strong\u003e Measures just 73.2 × 72 × 24 mm — easy to set up and ideal for maker and DIY projects.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFine-Tuning Support:\u003c\/strong\u003e Both voltage and internal resistance displays support display fine-tuning for calibration adjustments.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003ctable style=\"width:100%; border-collapse:collapse;\"\u003e\n  \u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003cth style=\"text-align:left;padding:6px 10px;border:1px solid #ddd;\"\u003eParameter\u003c\/th\u003e\n\u003cth style=\"text-align:left;padding:6px 10px;border:1px solid #ddd;\"\u003eValue\u003c\/th\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd style=\"padding:6px 10px;border:1px solid #ddd;\"\u003eWorking Voltage\u003c\/td\u003e\n\u003ctd style=\"padding:6px 10px;border:1px solid #ddd;\"\u003eDC 5 V (do not exceed rated voltage; 5 V adapter \u0026amp; Type-C cable NOT included)\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:6px 10px;border:1px solid #ddd;\"\u003eTesting Principle\u003c\/td\u003e\n\u003ctd style=\"padding:6px 10px;border:1px solid #ddd;\"\u003eAC 4-Wire Method\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd style=\"padding:6px 10px;border:1px solid #ddd;\"\u003eVoltage Test Range\u003c\/td\u003e\n\u003ctd style=\"padding:6px 10px;border:1px solid #ddd;\"\u003e0.001 V – 60.00 V, Resolution: 0.001 V\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:6px 10px;border:1px solid #ddd;\"\u003eInternal Resistance Range\u003c\/td\u003e\n\u003ctd style=\"padding:6px 10px;border:1px solid #ddd;\"\u003e0.1 mΩ – 6.999 Ω, Resolution: 0.1 mΩ\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd style=\"padding:6px 10px;border:1px solid #ddd;\"\u003eData Recording\u003c\/td\u003e\n\u003ctd style=\"padding:6px 10px;border:1px solid #ddd;\"\u003e99 groups (manual store \u0026amp; recall)\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:6px 10px;border:1px solid #ddd;\"\u003eGrading\u003c\/td\u003e\n\u003ctd style=\"padding:6px 10px;border:1px solid #ddd;\"\u003e4 grades: A, B, C, D\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd style=\"padding:6px 10px;border:1px solid #ddd;\"\u003eBacklight\u003c\/td\u003e\n\u003ctd style=\"padding:6px 10px;border:1px solid #ddd;\"\u003e1–9 levels adjustable\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:6px 10px;border:1px solid #ddd;\"\u003eAuto Power-Off\u003c\/td\u003e\n\u003ctd style=\"padding:6px 10px;border:1px solid #ddd;\"\u003e1–9 minutes (adjustable)\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd style=\"padding:6px 10px;border:1px solid #ddd;\"\u003eStandby Current\u003c\/td\u003e\n\u003ctd style=\"padding:6px 10px;border:1px solid #ddd;\"\u003e30 mA (screen on); \u0026lt;1 mA (screen off)\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:6px 10px;border:1px solid #ddd;\"\u003eSignal Cable\u003c\/td\u003e\n\u003ctd style=\"padding:6px 10px;border:1px solid #ddd;\"\u003eUSB-4P Signal Acquisition Cable\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd style=\"padding:6px 10px;border:1px solid #ddd;\"\u003eDimensions\u003c\/td\u003e\n\u003ctd style=\"padding:6px 10px;border:1px solid #ddd;\"\u003e73.2 × 72 × 24 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:6px 10px;border:1px solid #ddd;\"\u003eCountry of Origin\u003c\/td\u003e\n\u003ctd style=\"padding:6px 10px;border:1px solid #ddd;\"\u003eMade in China\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\n\u003ch3\u003eWhat's in the Box\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e1× Voltage \u0026amp; Internal Resistance Tester\u003c\/li\u003e\n  \u003cli\u003e\n\u003cem\u003eOR\u003c\/em\u003e 1× Test Clip\u003c\/li\u003e\n  \u003cli\u003e\n\u003cem\u003eOR\u003c\/em\u003e 1× Test Stand\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cem\u003eNote: 5 V power adapter and Type-C cable are NOT included. Battery is NOT included.\u003c\/em\u003e\u003c\/p\u003e\n\n\u003ch3\u003eWho Is This For?\u003c\/h3\u003e\n\u003cp\u003eThis tester is perfect for electronics enthusiasts, hobbyist makers, EV battery builders, RC car modders, solar storage DIYers, and anyone who needs to sort, match, or evaluate individual cells before assembling a battery pack. The 4-grade sorting system removes guesswork from cell matching and the on-device 99-group memory means you can test an entire batch without needing a laptop nearby.\u003c\/p\u003e\n\n\u003cp\u003eFor general guidance on electrical measurement standards and safety, visit the \u003ca href=\"https:\/\/www.nist.gov\/calibrations\" target=\"_blank\" rel=\"noopener noreferrer\"\u003eNIST Calibration Services page\u003c\/a\u003e — a trusted resource on metrology and measurement accuracy.\u003c\/p\u003e\n\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003ch4\u003eQ: What is the AC 4-Wire Method and why does it matter for internal resistance testing?\u003c\/h4\u003e\n\u003cp\u003eA: The AC 4-Wire (Kelvin) method uses separate current-source and voltage-sense leads, which eliminates the resistance of the test leads themselves from the measurement. This is essential when measuring very low internal resistance values (in the milliohm range), where even a few milliohms of lead resistance would otherwise skew the result. The result is a far more accurate reading of the battery cell's true internal resistance.\u003c\/p\u003e\n\n\u003ch4\u003eQ: What types of batteries can I test with this tester?\u003c\/h4\u003e\n\u003cp\u003eA: This tester supports any cell or battery with a voltage between 0.001 V and 60 V, making it compatible with standard lithium-ion (18650, 21700, pouch cells), LiFePO4, NiMH, NiCd, lead-acid, and many other rechargeable cell chemistries. The built-in 4056 charging module specifically supports ternary lithium and LiFePO4 cells for powering the unit itself.\u003c\/p\u003e\n\n\u003ch4\u003eQ: Does the tester need batteries to operate, and what power supply does it need?\u003c\/h4\u003e\n\u003cp\u003eA: The tester operates on DC 5 V via a Type-C connection. It does NOT come with a battery, 5 V adapter, or Type-C cable — you will need to supply your own standard 5 V USB adapter and Type-C cable. Do not exceed 5 V to avoid damaging the unit.\u003c\/p\u003e\n\n\u003ch4\u003eQ: How does the 4-grade sorting (A\/B\/C\/D) work?\u003c\/h4\u003e\n\u003cp\u003eA: You can configure reference thresholds for voltage and internal resistance. Once set, the tester automatically grades each measured cell into one of four categories (A, B, C, or D) based on how it compares to your defined thresholds — making it fast and easy to sort large batches of cells into quality tiers for battery pack building or quality control.\u003c\/p\u003e\n\n\u003ch4\u003eQ: Can I review previously saved measurements on the device?\u003c\/h4\u003e\n\u003cp\u003eA: Yes. The tester stores up to 99 groups of voltage and internal resistance data in on-device memory. You can scroll through and review all saved records directly on the 1.77-inch screen without connecting to a computer.\u003c\/p\u003e\n\n\u003cscript type=\"application\/ld+json\"\u003e{\"@context\": \"https:\/\/schema.org\", \"@type\": \"FAQPage\", \"mainEntity\": [{\"@type\": \"Question\", \"name\": \"What is the AC 4-Wire Method and why does it matter for internal resistance testing?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"The AC 4-Wire (Kelvin) method uses separate current-source and voltage-sense leads, which eliminates the resistance of the test leads themselves from the measurement. This is essential when measuring very low internal resistance values (in the milliohm range), where even a few milliohms of lead resistance would otherwise skew the result. The result is a far more accurate reading of the battery cell's true internal resistance.\"}}, {\"@type\": \"Question\", \"name\": \"What types of batteries can I test with this tester?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"This tester supports any cell or battery with a voltage between 0.001 V and 60 V, making it compatible with standard lithium-ion (18650, 21700, pouch cells), LiFePO4, NiMH, NiCd, lead-acid, and many other rechargeable cell chemistries. The built-in 4056 charging module specifically supports ternary lithium and LiFePO4 cells for powering the unit itself.\"}}, {\"@type\": \"Question\", \"name\": \"Does the tester need batteries to operate, and what power supply does it need?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"The tester operates on DC 5 V via a Type-C connection. It does NOT come with a battery, 5 V adapter, or Type-C cable — you will need to supply your own standard 5 V USB adapter and Type-C cable. Do not exceed 5 V to avoid damaging the unit.\"}}, {\"@type\": \"Question\", \"name\": \"How does the 4-grade sorting (A\/B\/C\/D) work?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"You can configure reference thresholds for voltage and internal resistance. Once set, the tester automatically grades each measured cell into one of four categories (A, B, C, or D) based on how it compares to your defined thresholds — making it fast and easy to sort large batches of cells into quality tiers for battery pack building or quality control.\"}}, {\"@type\": \"Question\", \"name\": \"Can I review previously saved measurements on the device?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Yes. The tester stores up to 99 groups of voltage and internal resistance data in on-device memory. You can scroll through and review all saved records directly on the 1.77-inch screen without connecting to a computer.\"}}]}\u003c\/script\u003e\n\u003cscript type=\"application\/ld+json\"\u003e{\"@context\": \"https:\/\/schema.org\", \"@type\": \"BreadcrumbList\", \"itemListElement\": [{\"@type\": \"ListItem\", \"position\": 1, \"name\": \"Home\", \"item\": \"https:\/\/kujrmc-0q.myshopify.com\/\"}, {\"@type\": \"ListItem\", \"position\": 2, \"name\": \"Electronics \u0026 Tech\", \"item\": \"https:\/\/kujrmc-0q.myshopify.com\/collections\/electronics-tech\"}, {\"@type\": \"ListItem\", \"position\": 3, \"name\": \"AC 4-Wire Battery Voltage \u0026 Internal Resistance Tester | 99 Groups\", \"item\": \"https:\/\/kujrmc-0q.myshopify.com\/products\/battery-voltage-internal-resistance-tester-ac-4-wire-99-groups\"}]}\u003c\/script\u003e","brand":"Vue","offers":[{"title":"Test Stand","offer_id":48747370447040,"sku":"844:203027855#Test Stand","price":41.99,"currency_code":"USD","in_stock":true},{"title":"Test Clip","offer_id":48747370479808,"sku":"844:203027854#Test Clip","price":41.99,"currency_code":"USD","in_stock":true},{"title":"Blue","offer_id":48747370512576,"sku":"844:203027853#Blue","price":41.99,"currency_code":"USD","in_stock":true},{"title":"Grey","offer_id":48747370545344,"sku":"844:203027852#Grey","price":41.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0772\/9338\/7968\/files\/S63cb73cb117e4d31af5407bcbede650ba.webp?v=1786199932","url":"https:\/\/vueselect.com\/products\/battery-voltage-internal-resistance-tester-ac-4-wire-99-groups","provider":"Vue","version":"1.0","type":"link"}