Safe 7.4V power with cell balancing, ready for your DIY projects.
This EVE 21700-50E 2S Battery Pack features two genuine EVE 21700-50E high-capacity cells connected in series (2S), delivering a nominal 7.4V voltage (8.4V full charge) and a solid 5000mAh capacity.
What sets this pack apart is its integrated Balanced Protection Board (BMS). The balancing function ensures both cells remain at the same voltage during charging, maximizing battery life and safety. The board also provides comprehensive protection against overcharge, over-discharge, over-current, and short circuits.
Pre-wired with a default XH2.54 2-pin connector, it is ready to plug into your custom electronics. Important: Due to the protection board, the continuous working current is limited to 4A (peak 8A). This pack is designed for low-to-medium current devices requiring 7.4V, such as portable audio gear, DIY electronics, and sensors. It is not intended for high-drain RC vehicles or power tools.
Key Features
2S Series Configuration (7.4V): Provides a higher 7.4V nominal voltage (8.4V full charge) for devices requiring more power than a single 3.7V cell.
Balanced Protection Board (BMS): The built-in balancing circuit keeps the two cells perfectly synchronized, preventing voltage drift and extending the pack's lifespan. Includes full overcharge, over-discharge, and short-circuit protection.
Safe 4A Continuous Current: Specifically designed for low-to-medium current devices. (Max continuous 4A, peak startup 8A).
Pre-wired & Plug-and-Play: Comes with a default XH2.54 2-pin connector (red/black leads, 8-15cm) for easy integration.
Compact 2-Cell Layout: Shrink-wrapped with the side protection board, measuring approx. 72mm (H) x 44mm (W) x 22mm (D).
Parameters
*Dimensions are approximate and include the protection board and heat shrink wrap. Please allow ±1-2mm tolerance.
Applications
Recommended For:
7.4V DIY Electronics: Perfect for audio amplifiers, portable speakers, and custom electronic circuits requiring 7.4V.
Portable Devices: High-capacity replacement for mini fans, radios, and devices designed for 2S Li-ion power (with a 4A limit).
Custom Power Banks: Build a 7.4V safe power bank with built-in protection.
Sensors & IoT Nodes: Reliable 7.4V power for long-term standalone deployments.
Not Recommended For:
High-Drain RC Models or Power Tools (>4A): Do not use in RC cars, drones, or power tools that draw more than 4A continuously. The protection board will trip and cut off power.
Devices Requiring Bare Cells: If your device's battery tray expects a standard flat-top cell, this pre-wired pack will not fit.
Single-Cell 3.7V Devices: Do not use this 7.4V pack in devices designed for 3.7V, as it will damage the device.
FAQ
Q1: What does "2S" mean and how does it differ from a single cell?
A: "2S" means 2 cells in Series. This doubles the voltage to 7.4V (8.4V full charge) while keeping the capacity at 5000mAh. It is used for devices that require higher voltage than a standard single 3.7V cell.
Q2: What is a "Balanced BMS" and why is it important?
A: A balanced BMS ensures that both cells are charged and discharged evenly. Without balancing, one cell might drift out of sync, reducing the overall lifespan and safety of the battery pack. This BMS automatically manages that balance.
Q3: What is the maximum discharge current?
A: Because of the protection board, the continuous working current is limited to 4A (with a peak of 8A for short startups). It is not designed for high-drain devices like RC cars or power tools.
Q4: Can I use this for my RC car or power tool?
A: No. RC cars and power tools typically require 15A to 30A+. The 4A limit on this protection board will cause it to shut off immediately under load.
Q5: How do I charge this 7.4V pack?
A: You must use a dedicated 2S Li-ion charger (8.4V output) or integrate it into a custom charging circuit. Do not use a single-cell 4.2V charger.
