0.28 Inch Ultra-small Digital DC Voltmeter with LED Display and Reverse Protection

This compact digital voltmeter offers precise voltage measurement for a wide range of DC applications. Whether you're monitoring battery levels in a car, motorcycle, or lithium pack, the clear 0.28-inch LED display provides quick readings with automatic decimal point placement. With a detection range of 2.4 to 40V DC and reverse connection protection, this meter is built to handle everyday use without risk of damage. Available in four LED colours—red, yellow, green, and blue—it fits neatly into dashboards, panels, or test setups.

Features and Construction

The voltmeter is designed for reliable performance in typical automotive and electronics environments. Its small footprint and simple two-wire connection make installation straightforward, even in tight spaces.

Voltage Range and Accuracy

The device measures from 2.4V up to 40V DC with an accuracy of 3‰. Auto-ranging decimal places show two digits below 10V and one digit above 10V, balancing precision and readability. Measurement rate is at least 200 ms per reading, providing stable updates.

LED Display Options

Choose from red, yellow, green, or blue 0.28-inch LED displays. The display automatically dims when the input voltage falls below 3.0V, but measurement accuracy remains unaffected. Brightness is sufficient for most indoor and shaded outdoor conditions.

Reverse Connection Protection

The meter includes built-in reverse polarity protection, meaning accidental reverse wiring will not damage the unit. A fine-tuning function allows for minor adjustments to ensure readings match your reference.

Uses and Placement

This voltmeter is suitable for a variety of low-voltage DC monitoring tasks. It handles both precise low-voltage readings and general-purpose higher voltage checks.

Battery Monitoring

Use it to check 18650 lithium cells, phone batteries, NiMH packs, or sealed lead-acid batteries. The auto-ranging decimal display gives accurate readings for both low and higher voltage cells.

Vehicle Electrical Systems

Ideal for monitoring the voltage of cars, motorcycles, or electric bicycles. Connect directly to the battery or interior wiring to keep an eye on charging system health.

Other Voltage Measurement

Suitable for any DC circuit within 2.4-40V, such as power supplies, solar panels, or laboratory experiments. The compact size allows panel mounting or temporary test leads.

Benefits and Buying Value

This voltmeter offers practical features at a reasonable cost. Its protection circuits and automatic display settings reduce the risk of mistakes and improve usability.

Easy Installation and Operation

With just two wires to connect, setup takes seconds. No external power supply needed for the basic measurement range—just connect across the voltage source. The reverse protection gives beginners peace of mind.

Clear Readout for Multiple Voltages

The LED display automatically switches between one and two decimal places, making it easy to read both 3.7V lithium cells and 12.6V car batteries without manual range selection.

Choice of Display Colour

Four colour options let you match the meter to your panel or preference. The display remains readable in typical indoor and vehicle interior lighting, though direct sunlight should be avoided.