Li-ion LiPo Battery Level Indicator Tester 1S–7S 3.7V–29.4V

Li-ion & LiPo Battery Level Indicator Tester – 1S to 7S (3.7V–29.4V)

Keep tabs on your battery charge at a glance with this compact 5-LED Battery Level Indicator Tester. Compatible with 1S through 7S lithium-ion, LiPo, lithium iron phosphate, lead-acid, and electric vehicle battery packs ranging from 3.7V to 29.4V, this slim module delivers an instant, intuitive readout of real-time charge status. At just 8 g and 40 × 15 × 2.5 mm, it fits easily into any build or battery enclosure.

Key Features

• Wide Voltage Compatibility: Supports 1S (3.7V) through 7S (29.4V) lithium-based battery packs — including 18650, LiPo, Li-ion, LiFePO4, lead-acid, and e-bike batteries.
• 5-LED Display: Ultra-thin design with four-stage power indication (25% / 50% / 75% / 100%) for a clear, intuitive charge level readout.
• Reverse Polarity Protection: Built-in reverse connection protection — if positive and negative leads are swapped, the module will not be damaged.
• Ultra-Low Standby Consumption: LED lights automatically turn off 3–10 seconds after button release; draws zero power when idle.
• Simple Push-Button Operation: Press the red button to activate the display; release to return to standby.
• Allowable Error: ±2% — ideal for general monitoring and field use.
• Durable High-Quality Build: Made in Mainland China using quality materials for long-lasting performance.

Specifications

LED Indicator Logic

The first (red) LED acts as the power/on indicator. The remaining four LEDs illuminate progressively based on measured voltage per cell (N = number of cells in series):

• 2nd LED ON: Battery voltage > N × 3.3V
• 3rd LED ON: Battery voltage > N × 3.5V
• 4th LED ON: Battery voltage > N × 3.7V
• 5th LED ON: Battery voltage > N × 3.9V

Note: 3.7V single-cell packs use 1 red + 4 green LEDs; all other voltage ranges use 1 red + 4 blue LEDs.

How to Use

1. Connect the positive and negative leads of the module to the corresponding terminals on your battery.
2. Press the red button — the LED indicators will light up showing the current charge level.
3. Release the button; the LEDs will turn off automatically after a 3–10 second delay.
4. If polarity is reversed, simply swap the leads — no damage will occur.

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Frequently Asked Questions

Q: Which battery types is this Li-ion battery level indicator tester compatible with?

A: This battery level indicator tester is compatible with a wide range of battery chemistries including lithium-ion (Li-ion), LiPo, lithium iron phosphate (LiFePO4), lead-acid, and electric vehicle battery packs. It supports 1S through 7S cell configurations covering voltages from 3.7V up to 29.4V fully charged.

Q: Does the battery tester draw power from the battery when not in use?

A: No. The module features an ultra-low standby design — the LEDs automatically switch off 3 to 10 seconds after you release the button, and the tester draws zero current when idle, preserving your battery's charge.

Q: What happens if I accidentally reverse the positive and negative connections?

A: This battery indicator module includes built-in reverse polarity protection. If you accidentally connect the leads the wrong way, the module will not be damaged. Simply disconnect and reconnect with the correct polarity.

Q: How accurate is the battery level reading?

A: The tester has an allowable error of ±2%, making it well-suited for general battery monitoring and field use. If your application requires very high measurement accuracy, a precision digital voltmeter may be more appropriate.