Does A Car Run Without A Battery?

Last Updated on April 28, 2021 by

A car can run without a battery when a highly efficient alternator is incorporated to provide sufficient power for all the car’s electrical needs. Sometimes a crank generator is necessary to start the car. However, it must be a super-capacity crank generator. Either way, this type of operation usually has high rates of load leakage per day. 

Operation Of A Car Without Battery – Main Aspects

AspectsDescription
Alternator Operation

When a car’s battery is disconnected from the alternator it should run on its own which may cause some errors in the vehicle, also the alternator current may not be sufficient.
Alternating Current PeaksSome alternating current peaks may occur and damage the different components of the vehicle’s electrical system.
ECU Malfunction
The most important on-board computer of the car may have false data due to improper operation of the electrical system.
Damage To The Electrical SystemWhen a high voltage level occurs in the electrical system, the various components involved can be permanently damaged.
Engine StartingAn alternative option to the battery is required to start the car such as a supercharger crank generator.

Does A Car Stop Running If The Battery Is Disconnected?

Of course, a car can continue to run after the battery is removed. Although this is possible, experts always recommend that the battery should not be disconnected at any time. The battery is responsible for providing electricity for starting and works together with the alternator.

However, a car battery not only provides this functionality but also takes care of other aspects. On many occasions, transient and AC peaks are directed to the ground thanks to the operation of the battery. Therefore, when the battery is no longer in the vehicle each one of these horsepower transients will be able to travel freely throughout the electrical system.

Of course, this is highly inadvisable as any of the semiconductor circuits in the vehicle will continue to operate at a high level of risk. Some of the systems that can be slightly or severely damaged are:

1. The car stereo

2. Cruise control

3. Memory seat adjustments

4. Speed sensitive steering

5. Engine computer or ECU

6. Any other electrical circuits or accessories in the vehicle

In many cases, however, some components such as the stereo or the various onboard computers may remain intact. However, this does not mean that the vehicle will be free from any kind of risk or damage. One of the most important components of the vehicle that can be damaged is the alternator.

As we have mentioned, the alternator is the second most important component of the vehicle that works in conjunction with the battery. So, when the car’s battery is no longer available the alternator will be the component that will have to deal with every aspect of the car’s electrical system.

At the very least, people who remove the battery from a car will need to purchase a new alternator in a very short time. Most likely the diodes in the alternator will burn out impairing the operation of the entire alternator. The control voltage input of the voltage regulator will also have a malfunction due to the disconnection of the battery.

Also, a very common situation is for the alternator voltage to rise to too high an amount. When this happens simply a large part of the car’s electrical system would be fried. So, the decision to remove the battery from the car can be much more costly than it seems.

Even disconnecting the battery when the car is still running could shut down the engine. In this case, it is difficult to know if the engine has shut down due to insufficient AC voltage. It could also happen that the car’s onboard computer in charge of timing the fuel mixture and also works with incorrect data.

So, here the ECU shuts down the vehicle due to sudden malfunction due to battery disconnection. So, to avoid all kinds of problems, it is advisable not to use a car or engine without a battery. Even if this is the only possibility to use a car it is better not to do it at all.

Of course, the various damages that can occur in the vehicle do not usually happen for good. However, it only takes too high a voltage to fry the entire electrical system and cause extensive damage to the vehicle. All of this could render the car useless if you don’t have a large budget to replace the many parts that can be damaged.

Disconnecting The Battery While The Car Is Running 

Some people may choose to disconnect a car’s battery to check that the alternator is working properly. Some people claim that the engine should continue to run if the alternator is working properly and the battery has been disconnected once the car is running.

In many cases, it can be detected that the alternator does not provide enough electrical current to keep the engine running. Although this is a technique widely used by mechanics, it can cause some damage to the vehicle’s electrical system. Therefore, it is advisable as an alternative to opting for other ways to check the proper functioning of the alternator.

One of them is to have a multimeter to avoid any damage to the vehicle. Removing the battery can produce a higher voltage through the alternator. Undoubtedly, this can slightly or affect several sensitive components of the vehicle. The on-board computer could lock up if the alternator intermittently provides power.

Instead, it is much more advisable to use a multimeter or a voltmeter. In this way, the battery voltage can be checked during turning the car off and on. When the alternator is running, you can detect the return of some power to the battery. Of course, this does not mean that the alternator is working in the best way.

However, if the adequate voltage is not detected at the alternator, it means that it is a malfunctioning component. Probably the best option here is to replace the alternator to have an efficient electrical system. 

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