DC 2.4–40V Mini LED Digital Voltmeter – 0.28" Panel Tester

DC 2.4–40V Mini LED Digital Voltmeter — Compact & Accurate Voltage Tester

This compact 0.28-inch LED digital voltmeter makes monitoring DC voltage fast, easy, and precise. Whether you're checking the charge on a lithium battery pack, verifying your car or motorcycle's electrical system, or testing a DC power supply in your workshop, this tiny panel meter delivers clear, accurate readings every time. Available in your choice of Red, Green, Blue, or Yellow LED display to suit your setup.

Key Features

• Wide Measurement Range: DC 2.4V–40V (varies slightly by colour variant) with built-in reverse-polarity protection so incorrect wiring won't damage the unit
• High Accuracy: 3‰ measurement accuracy with a fast update rate of ≥200ms per reading
• Smart Decimal Display: Shows two decimal places for voltages below 10V and one decimal place above 10V — giving you the precision you need at every level
• Ultra-Compact 0.28" LED Panel: Designed for tight spaces — perfect for battery enclosures, DIY power banks, vehicle dashboards, and lab benches
• Simple 2-Wire Connection: Comes pre-wired and ready to connect; easy to install and remove without specialist tools
• Fine-Tuning Function: On-board calibration trim allows you to zero-in readings for maximum accuracy
• Low Power Draw: Working current under 30mA keeps parasitic drain to an absolute minimum
• Colour Options: Red, Yellow, Green, or Blue LED display — choose the colour that best suits your build

Technical Specifications

Typical Applications

• 18650 lithium cells, mobile phone battery packs, and NiMH battery assemblies
• Car, motorcycle, and electric-vehicle battery monitoring
• DIY DC power supplies and bench power units
• Electric bicycle battery management
• Scientific research, teaching, and electronics prototyping

Important Notes

• Maximum input voltage must not exceed 40V to avoid damage
• Display brightness may reduce slightly when the measured voltage falls below 3.0V; this does not affect measurement accuracy
• Avoid direct sunlight on the display for best visibility
• Manual measurement: please allow ±1–3mm dimensional tolerance
• Screen colours in photos may vary slightly from actual LED colour due to monitor differences

Made in Mainland China.

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Frequently Asked Questions

Q: What types of batteries can this digital voltmeter measure?

A: This voltmeter is designed for a wide range of DC voltage sources within the 2.4V–40V range. It works with 18650 lithium cells, mobile phone lithium battery packs, nickel-metal hydride (NiMH) battery assemblies, as well as car, motorcycle, and electric-vehicle 12V or 24V battery systems.

Q: Does this voltmeter protect against reverse polarity?

A: Yes. The unit features a built-in reverse-polarity protection circuit. If the wires are accidentally connected the wrong way, the meter will not be damaged — giving you peace of mind during installation.

Q: Can I adjust the reading for more accurate results?

A: Absolutely. The voltmeter includes a fine-tuning (calibration trim) function that lets you make small adjustments to align the displayed reading with a known reference, ensuring the highest possible accuracy for your specific application.

Q: Is this voltmeter suitable for permanent panel installation?

A: Yes. Its ultra-compact 0.28-inch footprint is specifically designed for panel mounting in tight spaces such as battery enclosures, DIY power bank housings, vehicle dashboards, and control boxes. The simple 2-wire connection makes both installation and removal quick and straightforward.