At the core of it, combustion-powered vehicles need three basic things to run, fuel, air and ignition. While the alternator of the vehicle should be able to generate enough electricity to provide adequate ignition while the vehicle is running. The battery is still needed to start the vehicle and, in some cases, assist with running certain auxiliaries and even the lights.
But before you sell your car with our Instant Offer tool and search for new or used models on AutoTrader. Let us first tell you if a dead battery can be jumpstarted.
Related: Which is the best car battery?
Car battery basics
In order to answer the question of whether you can jumpstart a car with a dead battery, we first need to understand the car battery itself. A car battery will usually come in 12v DC with a cold cranking amperage rating. This is an indication of how much power in amps the battery has low down to crank the engine in cold weather. Typically, batteries with a higher amperage rating will be paired with bigger petrol and diesel engines, as they need a lot of power to turn them.
Battery life
When a car battery has gone flat, it means that the amperage rating has dropped considerably and cannot produce enough power to turn the engine. In some cases, a voltage test will show 12v across the battery, but it has little to no cranking amperage and thus will not start a car. In these cases, charging the battery will restore it to working order if it was simply a battery drain, such as leaving the lights on.
Can a dead battery be jumpstarted?
If a battery has reached the end of its working life, usually in about two years, it will no longer take an electrical charge and will no longer be able to crank the engine; in this case, the battery can longer store the required amperage and voltage to run the engine, and even if you attempt to jump start it, it will not power the engine’s electrical systems.
There is a difference between a flat battery and a dead battery. Flat batteries have just used up all their charge and can be jumped from another battery or push-started and will continue to work correctly once charged by the car's alternator. A dead battery is just that, dead; there is no residual charge left and, more often than not, will have a dead cell that drains the other cells of charge continuously. Dead batteries will not take charge and, therefore, cannot be jumpstarted.
