* Chemical Reaction Slowdown: Car batteries are lead-acid batteries that rely on a chemical reaction to produce electricity. Cold temperatures slow down this chemical reaction, reducing the battery's ability to generate the necessary current to crank the engine.
* Increased Battery Resistance: Cold temperatures increase the internal resistance within the battery, further hindering the flow of electricity. This means even if the battery has a decent charge, it might struggle to supply the high current needed to turn the starter motor.
* Thicker Oil: Cold weather also thickens engine oil, making it harder for the engine to turn over. This requires even more power from the battery, putting extra strain on an already weakened system.
* Increased Drain on the Battery: Cold weather often leads to using more electrical components like headlights, defroster, and heated seats, which can further deplete the battery's charge overnight.
In essence, the combination of a slower chemical reaction in the battery, increased internal resistance, thicker oil, and increased electrical demands in cold weather often result in a battery that can't deliver enough power to start the car. A jump start provides the extra power needed to overcome this temporary deficiency.
