Winter storage requires extra attention because cold temperatures accelerate LiPo degradation and increase internal resistance. I learned this the hard way after leaving batteries in my garage one winter and finding them puffed and unusable by spring.
First, charge each pack to storage voltage before putting them away. This means 3.8 to 3.85 volts per cell, which sits around 50-60% capacity. Most modern chargers have a dedicated storage mode that handles this automatically. Never store LiPo batteries fully charged or depleted, as both states cause permanent capacity loss and can lead to dangerous swelling.
Temperature is critical during winter. LiPo batteries should never be stored below 10°C or above 30°C for extended periods. Cold temperatures cause the electrolyte to thicken and can lead to lithium plating on the anode, permanently reducing performance. I keep mine in a climate-controlled room, not in the garage or shed where temperatures fluctuate. If you only have unheated spaces available, bring the batteries inside your main living area.
Check voltage levels monthly throughout winter. LiPo batteries self-discharge faster in warmer conditions but still lose charge even in cool storage. If any cell drops below 3.7V, recharge to storage voltage immediately. I set a phone reminder for the first of each month to verify my packs with a cell checker. This five-minute routine has saved me hundreds in replacement costs.
Use a proper storage container like a LiPo safety bag or metal ammo box, and keep batteries away from flammable materials. I stack mine vertically in a fireproof bag inside a metal cabinet, which provides both organization and safety.
Remove batteries from your drones before storage. Leaving them connected creates parasitic drain from flight controllers and receivers, even when powered off. I once drained three packs to zero this way, and they never recovered their original capacity.
When spring arrives, inspect each battery carefully before use. Look for any puffing, damaged wires, or connector issues. Let cold batteries warm to room temperature naturally before charging or flying. Charging a cold LiPo can cause internal damage you won't see until the pack fails mid-flight. I wait at least two hours after bringing batteries in from cold storage before putting them on the charger.
Following these practices, my oldest race packs are now three years old and still deliver 90% of their original punch.
