Introduction
This manual provides essential instructions for the safe and effective use of the Liter Energy Battery 402025 LiPo 3.7V 135mAh rechargeable lithium polymer battery. Please read this manual thoroughly before installation and operation to ensure optimal performance and longevity of your battery.
Safety Information
Lithium Polymer (LiPo) batteries require careful handling. Adhere to the following safety guidelines:
- Temperature: Do not expose the battery to high temperatures, direct sunlight, or heat sources.
- Disposal: Do not dispose of the battery in fire or water.
- Charging: Avoid overcharging or over-discharging the battery. Use only compatible chargers.
- Physical Damage: Do not puncture, disassemble, or modify the battery. If the battery swells, leaks, or shows any signs of damage, discontinue use immediately and dispose of it properly.
- Static Sensitivity: This device is static sensitive. Handle with care and avoid unnecessary contact with the terminals.
- Compatibility: This battery has a discharge rate below 5C and is not suitable for high-current applications such as RC drones, RC cars, RC planes, or RC boats. Using it in such devices may result in insufficient power delivery and potential damage.

Image: Warning label indicating the battery is a static-sensitive device and should not be handled by unauthorized personnel.
Product Overview
The Liter Energy Battery 402025 is a compact 3.7V 135mAh LiPo battery designed for various portable electronic devices. It features an integrated Protection Circuit Module (PCM) to safeguard against common battery issues.

Image: A general view of the Liter Energy Battery 402025, showing its compact size and red/black wires.
Dimensions
The battery measures approximately 27mm x 20mm x 4mm.

Image: Diagram illustrating the dimensions of the 402025 battery: 27mm length, 20mm width, and 4mm thickness, with a 25mm cable length.
Protection Circuit Module (PCM)
The integrated PCM provides multiple layers of protection:
- Overcharge Protection
- Over-discharge Protection
- Overcurrent Protection
- Short-circuit Protection
- Over-temperature Protection

Image: An exploded view diagram showing the internal components of the LiPo battery, including the LiPo cell, Kapton adhesive, and the PCM with its two cables (positive red, negative black).
Specifications

Image: A table detailing the product parameters for the LiPo 3.7V 135mAh battery, including rated capacity, nominal voltage, discharge cut-off voltage, charging voltage, internal impedance, standard charge/discharge, fast charge/discharge, maximum continuous charge/discharge current, and operating/storage temperature ranges.
| Parameter | Value |
|---|---|
| Model Number | 402025 |
| Battery Type | Lithium Polymer (LiPo) |
| Nominal Voltage | 3.7 V |
| Rated Capacity | 135 mAh |
| Dimensions (L x W x H) | 27 x 20 x 4 mm (± 0.5 mm) |
| Weight | 4 Grams |
| Protection Circuit | Integrated PCM (Overcharge, Over-discharge, Overcurrent, Short-circuit, Over-temperature) |
| Discharge Rate | Below 5C |
| Reusability | Rechargeable |
| Compatible Devices | Mobile phones, web phones, intercoms, Bluetooth headsets, notebooks, PDAs, portable electrographs, portable printers, GPS, digital cameras, camcorders, portable DVDs, portable TVs, MP3, MP4 players, miner's lamps, reflectors, toys. |
| Non-Compatible Devices | RC drones, RC cars, RC planes, RC boats (due to low C-rating). |
Setup
- Verify Compatibility: Before installation, ensure the physical dimensions (27x20x4mm) and electrical specifications (3.7V, 135mAh) of this battery are compatible with your device's requirements.
- Prepare Device: Power off your device and open the battery compartment according to your device's instructions.
- Connect Battery: Carefully connect the battery's positive (red) wire to the corresponding positive terminal and the negative (black) wire to the negative terminal of your device. Ensure connections are secure and correct polarity is maintained.
- Secure Battery: Place the battery securely within the compartment, ensuring no wires are pinched or damaged. Close the battery compartment.

Image: Visual representation of compatible devices (e.g., phones, smartwatches, GPS) and non-compatible devices (e.g., RC drones, cars, planes, boats) for the battery.
Operating Instructions
Charging
- Use only the original charger or a compatible LiPo battery charger designed for 3.7V single-cell batteries.
- Connect the charger to the battery and a power source.
- Monitor the charging process. Disconnect the charger once the battery is fully charged to prevent overcharging. The PCM will provide protection, but it is best practice to avoid prolonged charging after full capacity is reached.
- Typical charge time is approximately 2-3 hours for a standard charge (0.2C). Fast charge (0.5C) takes approximately 1.2 hours.
Usage
- Operate the battery within its specified operating temperature range (Charge: 0-45°C, Discharge: -20-60°C).
- Avoid deep discharge. The PCM will cut off power at 3.0V to protect the battery.
- Do not exceed the maximum continuous discharge current (1C).
Maintenance
- Storage: Store the battery in a cool, dry place, away from direct sunlight, moisture, and extreme temperatures. For long-term storage (less than 1 year), maintain a temperature of 20-25°C. For shorter periods (less than 3 months), store at 20-40°C.
- Charge Level for Storage: For optimal long-term storage, keep the battery at a partial charge (around 3.7V - 3.8V), not fully charged or fully discharged.
- Cleaning: Keep battery terminals clean and free from dirt or corrosion.
- Inspection: Periodically inspect the battery for any signs of swelling, leakage, or physical damage.
Troubleshooting
- Battery Not Charging:
- Ensure the charger is properly connected to both the battery and the power source.
- Verify that the charger is compatible with 3.7V LiPo batteries.
- Check for any visible damage to the battery or charging cables.
- Short Operating Time:
- Ensure the battery is fully charged before use.
- The battery may be nearing the end of its lifespan.
- The device's power consumption might be higher than expected.
- Device Not Powering On:
- Confirm that the battery is correctly installed and the wires are securely connected with correct polarity.
- Check if the battery has sufficient charge.
- Rule out other potential issues with the device itself.
Warranty and Support
For customer service inquiries, warranty claims, or technical support, please contact the manufacturer directly.
- Website: thestock.es
- Phone: (+34) 699 345 747
Information regarding spare parts availability is currently not provided by the manufacturer.