Build a Working EV Battery Balancer with Arduino Mega — Learn Passive Cell Balancing

Every part needed, pre-tested for compatibility, with an AI build companion trained on this exact project. Shipped from Bengaluru in 3-5 days.

Step inside the battery management system of an electric vehicle without the high voltage. This kit puts you in the engineer’s seat — you’ll wire four INA219 current/voltage sensors across four cells in series, let the Arduino Mega detect the smallest voltage mismatch, and watch relays kick in with bleeder resistors to bring every cell back in line. The same passive balancing principle keeps thousands of lithium-ion cells healthy inside a Tata Nexon or Tesla Model 3.

What You'll Build

A bench-top demo you can power with a standard 9V battery (snap provided) or a 4S Li-ion pack. The 0.96‑inch OLED cycles through real-time voltage readings of each cell, and when one cell drifts too high, its dedicated relay energises a 10Ω bleeder resistor to gently discharge it. The result is a living model of how EV battery packs prevent overcharge and extend cycle life.

What You'll Learn

• Measure cell-level voltage and current simultaneously using four INA219 sensors over the I2C bus
• Expand a single I2C port into eight via the TCA9548A multiplexer to handle four identical sensor addresses
• Code a hysteresis-based balancing algorithm that switches relays on and off based on voltage thresholds
• Interpret real-time BMS diagnostics on an OLED display and log performance while parasitic loads are applied

Kit Contents

Why Buy This Kit Instead of Sourcing Parts Separately

Who This Kit Is For

CBSE Class 11‑12 students who want a hands‑on entry into power electronics, ATL Tinkering Lab teams exploring energy‑storage projects, B.Tech ECE/EEE first‑year students preparing for mini‑projects or Smart India Hackathon, and curious hobbyists who want to see how a battery management system really works before diving into real EV packs.

Built and Backed by Compoden

Every Compoden kit ships with an AI build companion trained on this exact project — accessible via a QR code on the box, with WhatsApp and email backup. We've spent 10 years building projects for makers, schools, and institutions across India. If a part fails because of a manufacturing defect, replace it free within 7 days.