Getting Started with Starting Systems

Getting Started with Starting Systems

Learn how 12-volt batteries, solenoids, and starter motors work together to get vehicles running.


Hello and welcome. Today we are going to dig into the starting system of a car. These systems have come a very long way since the early days. In the days of the Model Ts and such, cars had cranks. Many times it took two people to start a vehicle, one to crank and one to advance the spark and throttle at just the right time. Be careful though, if it backfires, it could likely break the cranker’s arm. Luckily, a man named Charles Kettering invented the first vehicle self-starter. This stopped the broken arms and virtually revolutionized the automotive industry.

First thing we need to remember is that without this usually overlooked system, nobody is going anywhere. We should also note that this session is mainly focused on a typical ICE vehicle. Hybrids do have start systems that is generally similar to an ICE application, but there are some technical differences due to the vehicle’s ability to operate on its own electrical motor.

First and foremost, all starter systems need an electrical source. Since almost all vehicles today use a 12-volt starting system, this is supplied by a battery. This component is not given much consideration until it fails to deliver the current required to start the vehicle. Failure is not always the battery itself. Many times it is the cables or the terminals themselves that prohibit starting. Proper routine maintenance can prevent all of these issues.

The battery relies on a large copper cable to carry large amounts of current to a solenoid. This solenoid acts as a switch between the battery and the starter. This allows smaller wires to be used up to the key switch that is our next component in the system. This key-activated switch, when activated, sends current to the solenoid that then directly connects the starter motor to the battery. Ignition switches have become more sophisticated over the years and can be a source of trouble. Many are an integral part of the anti-theft system and are very complicated.

Once the current reaches the starter motor, there is a device to actually engage the gears to the flywheel. Some starters use a gear or screw drive to move the gears into place while other designs use the mechanical action of the solenoid to push the gears into position. Typically, the starter has a very small gear on it and the flywheel gear is a very large gear. This gives the starter the needed torque to overcome the natural resistance of the engine. Starters and solenoids are subject to wear from low-current situations like we discussed above. This creates excessive heat and possible arcing in the components.

How does your vehicle owner care for his or her starting system? It’s all about the current required for starting. Care should be taken of all battery cables and terminals. This will go a long way to keeping your system grinding away. Thanks for being with us, and have a great day.

This video is sponsored by The Group Training Academy.

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