How to Build a 40x 18650 Battery Holder for Mass Voltage Leveling (ASMR)

In this video, I’m building a massive, custom 40-slot 18650 battery holder designed for mass parallel top-balancing and voltage leveling. When dealing with large DIY battery projects, equalizing cells individually takes forever. This heavy-duty 40-cell balancing rig allows you to safely level the voltage of an entire batch of lithium-ion cells at once before spot-welding them into packs. ​Watch the meticulous ASMR workshop process as I combine multiple modular matrix brackets, align the connections, and solder heavy-gauge copper wire busbars to handle the shared balancing currents. I will also be integrating an accurate digital mini volt meter to track the real-time stabilization of the entire 40-cell grid. ​What you will see in this video: ​Planning and interlocking modular spacers for a 40-cell matrix. ​Preparing and tinning ultra-thick copper rails for low-resistance parallel distribution. ​Rhythmic, repetitive soldering of 40 positive and negative contacts (pure ASMR). ​Installing a digital LED voltmeter for real-time voltage monitoring. ​The satisfying sound of loading the grid with 40 green and blue 18650 cells. ​Safety Reminder: When populating a massive 40-cell parallel board, ensure all inserted cells are already relatively close in voltage (within 0.1V - 0.2V) to prevent massive current rushes and heavy sparking between cells! ​If you enjoy large-scale battery DIYs, electronic station builds, and relaxing workshop ASMR, please SUBSCRIBE to the channel!