A small battery powered motor can actually use more energy if you lower the voltage.
Most people assume that lower voltage always means lower power consumption for a DC motor. This study found a non-monotonic relationship where there is actually a specific sweet spot for minimum energy. If you go below this voltage, the motor becomes less efficient and wastes more energy to complete a single cycle. This sweet spot changes in real-time as the weight or load on the motor shifts. This discovery allows for new smart controllers that can track this peak efficiency to make batteries last much longer.
Real-Time Minimum-Energy Operating-Point Tracking for Battery-Powered Micro DC Motors Under Dynamically Variable Loading
arXiv · 2604.26335
Micro DC brushed motors are widely deployed in battery-powered biomedical systems, where limited energy budgets and variable physiological loading impose stringent efficiency and safety constraints. However, conventional actuation strategies rely on conservative voltage margins to avoid stalling, leading to systematic energy inefficiency. Furthermore, existing methods primarily optimize steady-state performance, neglecting the energy required to complete individual actuation cycles under dynamic