Sure thing, let’s break it down step by step. First, we need the thermal envelope of each cell. Grab the datasheet for the 18650 cells you’re using – look for the maximum continuous discharge temperature (usually around 60 °C). Then pick a heatsink that keeps the cell surface below that, say 45 °C under load. A 3‑inch aluminum fin with 2 mm pitch gives a good surface area; the manufacturer’s spec says 0.65 W/°C thermal resistance. Next, airflow. A low‑noise 120 mm fan at 150 m/s can pull about 80 CFM through the pack. Place a 2‑inch filter at the intake to keep dust out, then route the exhaust along the outer rail with a 90° elbow to keep the fans balanced. If you want a self‑regulating loop, add a thermistor on the exhaust line and feed it back to the fan controller – a simple 5‑V PWM loop will do. Wire everything color‑coded: red for power, blue for control, green for thermistor, black for ground. Keep the thermistor probe close to the hottest cell, not just the midpoint. Finally, test it at 1.5× the rated current and record the temperature rise. If it hits above 50 °C, add a second fan or a thicker fin. Keep a log of all component parts and the exact dimensions; that’s what turns a good design into a reliable one. Happy building!

Got it, I’ll keep everything in the datasheet limits, lock down the logs, and run the 1.5× test before any handover. Discipline is the only way to keep the pack stable.