I’m talking cold that’ll freeze the snot right in your nose. I’m talking wind that’ll cut through your jacket and carve you up like a Ginsu knife. – Saul Goodman
Winters in Michigan can be rough, with the snow comes sub-zero temps and extreme wind chills. None of these things are very good for your camera battery performance. But why is that?
To understand this we first need to understand what a battery is. In simple terms a battery is a number of electrical cells connected together that convert chemical energy into electrical energy in order to produce an electric current. Within those electrical cells you have two electrodes (an anode and cathode), separated by a separator, and an electrolyte that have been arranged so that the chemical reaction produces some electromotive force – not to be confused with voltage, electromotive force is simply the amount of energy supplied by the cell to each unit of charge passing through the cell, whereas voltage is the difference in electrical potential between the cathode and anode.
It’s been a while since we have seen a picture and this is a photography blog so… Hey look! A picture!
This image illustrates what we just discussed: Two electrodes, separated by an electrolyte, in order to provide energy to a load – such as a camera. Now let’s take a closer look at whats actually happening.
An electrical device, such as a camera, requires electrical current in order to function. This current is simply a stream of electrons that flows through an electrical circuit. But where do these electrons flow from and where do they end up….
Well, the answer to that is the is in the battery!
It starts at the anode. The anode (through a process called oxidation) releases electrons to the electrical circuit, they flow from the battery through the electrical load (camera, cell phone, external flash…) and then flow to the cathode which collects them in a process called reduction. Combined this oxidation and reduction reaction is called a redox reaction.
(One point to note here is while conventional current does flow from positive to negative, here we are talking about electron flow – which is from negative to positive.)
Ok… So I now know the parts of a battery and how energy flows though it. But you still haven’t explained how this has anything to do with cold weather performance!!!
It all comes down to chemistry and something called collision theory, which states that the speed of a chemical reaction is proportional to the frequency of collisions between particles. Which means that chemical reactions will happen faster when particles collide more frequently. Collision theory also states that increasing temperature leads molecules to travel faster and collide more violently. So a faster chemical reaction requires that particles to collide more frequently, and particles collide more frequently in warmer temperatures.
So let’s summarize.
A battery provides power to a device (your camera) by converting chemical energy to electrical energy in a process called a redox reaction. The speed of this reaction is proportional to the speed at which the particles in the reaction collide, which is directly effected by the temperature at which the reaction occurs. So at colder temperatures, you have slower chemical reactions, which produces less electrical current – which means that your device is not getting enough energy to function properly. So tuck those batteries in an inside pocket close to your skin and let your body heat keep them nice and warm.