Why Do Batteries Discharge More Quickly in Cold Weather?

Understand the Effect of Temperature on Batteries

Cold batteries go dead more quickly! Temperature affects how charge is held and released.
Cold batteries go dead more quickly! Temperature affects how charge is held and released. Tom Stewart / Getty Images

If you live in a place that gets a cold winter, you know to keep jumper cables in your car because there's a good chance you or someone you know will have a dead battery. If you use your phone or camera in really cold weather, its battery life drops, too. Why do batteries discharge more quickly in cold weather?

The electric current generated by a battery is produced when a connection is made between its positive and negative terminals.

When the terminals are connected, a chemical reaction is initiated that generates electrons to supply the current of the battery. Lowering the temperature causes chemical reactions to proceed more slowly, so if a battery is used at a low temperature then less current is produced than at a higher temperature. As the batteries run down they quickly reach the point where they cannot deliver enough current to keep up with the demand. If the battery is warmed up again it will operate normally.

One solution to this problem is to make certain batteries are warm just prior to use. Preheating batteries is not unusual for certain situations. Automotive batteries are protected somewhat if a vehicle is in a garage, although trickle chargers may be needed if the temperature is very low. If the battery is already warm and insulated, it may make sense to use the battery's own power to operate a heating coil.

Smaller batteries may be kept in a pocket.

It is reasonable to have batteries warm for use, but the discharge curve for most batteries is more dependent on battery design and chemistry than on temperature. This means that if the current drawn by the equipment is low in relation to the power rating of the cell, then the effect of temperature may be negligible.

On the other hand, when a battery is not in use, it will slowly lose its charge as a result of leakage between the terminals. This chemical reaction is also temperature dependent, so unused batteries will lose their charge more slowly at cooler temperatures than at warmer temperatures. For example, certain rechargeable batteries may go flat in approximately two weeks at normal room temperature, but may last more than twice as long if refrigerated.

Bottom Line on the Effect of Temperature on Batteries

  • Cold batteries hold their charge longer than room temperature batteries; hot batteries don't hold charge as well as room temperature or cold batteries. It's good practice to store unused batteries in a cool location.
  • Cold batteries discharge faster than warmer batteries, so if you're using a cold battery, keep a warm one in reserve. If batteries are small, keeping them in a jacket pocket is usually good enough.
  • Some types of batteries are adversely affected by high temperatures. A runaway effect can occur, potentially leading to a fire or explosion. This is commonly seen in lithium batteries, such as you might find in a laptop or cell phone.