Keep power tool batteries safe in cold: use insulation, manage moisture, apply corrosion protection, and rotate indoors nightly to preserve capacity. Most modern power tools use lithium-ion batteries. There's a whole host of reasons why these became the industry standard. They charge faster, can hold a higher capacity of electricity, and can maintain that capacity for longer. Leaving tool batteries in cold temperatures can have significant effects on their performance and lifespan. Below freezing, chemical reactions slow, voltage sag worsens, and permanent capacity loss can occur. In this comprehensive guide, we will explore everything you need to know about protecting your lithium.