Easy Method to Detect a Weak Hybrid Battery Module with a Multimeter During Pack Discharge. Learn the simplest way to identify weak battery modules in any hybrid high-voltage battery pack using just wearing class 0 insulted safety gloves and a CAT IV multimeter. By measuring the voltage of individual modules during a collective discharge, you can quickly pinpoint imbalances. Modules with lower voltages compared to others indicate weakness, helping you diagnose issues effectively without complica