Not the only, but the primary purpose of a battery in a car or boat is to provide enough power sufficient to start the engine. The rating that is given to a battery is called CCA, or Cold Cranking Amps. This is effectively the amount of power, measured in amps, that can be delivered by the battery in a short period of time. Two major factors that impact this on a battery is temperature and age.
Kind of like me.
The more energetic, warm, excited I am the more motivated I am to get going on my run. If I am cold, lethargic and slow it takes quite a bit of energy to get me going. Same is true with a battery. The colder the outside temperature, the more challenging it is for a battery to provide the necessary amperage to the engine’s starter motor. The other factor is age. The older I get the harder it seems to get that lift I need to get started. Same with a battery. Overtime the battery breaks down and even though it may hold a full charge, it will not be able to delivery the power fast enough to crank an engine.
Now they slap stickers on the side of batteries indicating their expected performance rating over a given lifetime. I do not have a sticker, and I certainly do not have a CCA rating. Rather I just have me, alone, in the morning, starting at a dark road side with no other motivation then setting my watch to “start.”
Guy Reams