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AMD
AMD, Master Technician
Category: Car
Satisfied Customers: 2701
Experience:  L1 Advanced Level Diagnostics Specialist
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Hello. This is a generalized question about any vehicle.

Customer Question

Hello. This is a generalized question about any vehicle. What would you consider the heart of a vehicle and is it possible for a vehicle to run without a battery? If you can start it and then remove the battery, how long can the alternator run wihtout the battery?
Submitted: 1 year ago.
Category: Car
Expert:  AMD replied 1 year ago.

AMD :

Hello and thank you for trusting us with your Car question, My name is XXXXX XXXXX X will be assisting you today.

AMD :

Are you available to discuss your question at this time?

AMD :

Hello! how are you doing today?

Customer:

yes, go ahead. I'm doing great. I'm trying to relate my question to the human body. sometimes it's easier to explain things to clients and they know what i'm talking about.

AMD :

OK I will answer the battery\alternator part of the question first then we'll talk about the heart of the vehicle part, is that OK?

Customer:

go ahead

AMD :

Thank you. Now you can start the car then remove the battery. However you will put the alternator under extreme stress and I expect the alternator to fail very quickly as a result of this and allow me to explain why

AMD :

The alternator has two functions once the engine is running. It's main function is to supply power to all the electrical systems of the vehicle. The second function is to maintain a constant charge to the battery and keep it charged.

AMD :

When you disconnect the battery you have created an open circuit

AMD :

the alternator is not a computer and the circuit it has is a very basic one

AMD :

it will assume that the battery is very undercharged and it will start to increase the charge amperage to the battery trying to charge it

AMD :

it will continue to do this until it produces maximum amperage to charge the battery.

AMD :

running an alternator at fully capacity is something it's designed to do but not for a long time.

AMD :

most alternators are rated between 90-150 amps

AMD :

however most of the time they will run at 50% of their maximum capacity

AMD :

When you disconnect the battery with the engine running the alternator will go gradually to full capacity. running the alternator at full capacity for a long time will basically overheat the alternator over time and burn it

AMD :

So to answer your question in a direct answer, yes you can disconnect the battery when the engine is running but you are stressing the alternator and it will not last long. I would say safely you can leave it disconnected for up to 5 minutes after that damage to the alternator is defenite.

AMD :

Is this making sense?

Customer:

Yes, go on.

AMD :

OK So there isn't really a direct accurate answer on how long the alternator will run without the battery, but from a technical stand point and from my experience not long. I mean you can run an engine without oil but how long is it going to last? no one can tell for sure until you try it because it will vary greatly.

AMD :

Before I start talking about the heart of the vehicle, did you have any questions about the alternator\battery?

Customer:

If you are going to talk about the heart of the vehicle is it safe to say it isn't the battery?

AMD :

Well the car will have 2 parts. There's the electrical system and then there's the mechanical system. One depends on the other for the car to run. For example if the electrical system is working properly but there's a mechanical issue then the car won't run and vice versa.

AMD :

So although it's hard to specify one part I will do my best.

AMD :

For the electrical system of the vehicle yes the battery and the alternator are the heart.

AMD :

when the engine is not running the battery is the heart of the electrical system. once the engine is running the alternator takes over 75%

AMD :

When it comes to the mechanical side of the engine alone the oil pump is the heart of the engine.

AMD :

If there's no oil pressure the engine will have oil starvation and will seize up and stop working which makes a healthy electrical system useless.

AMD :

There are other components that could also be described as the heart of the vehicle like a fuel pump or starter but they are not primary

AMD :

To compare it to human parts, if the heart is working but the nervous system is not then the body will work but not fully

AMD :

Is it making sense?

Customer:

Yes. This is what I wanted because it is similar to what the body does. Sometimes things don't shut down all at once and other vital organs take over until it becomes overwhelming. Thank you very much. I may need more answers later.

AMD :

You're welcome. Let me know if you have other questions in the future.

AMD :

A positive rating for my input would be greatly appreciated.

AMD :

Thank you for using Justanswer.com

Customer:

Ok. Thank you

AMD :

You're welcome.

AMD, Master Technician
Category: Car
Satisfied Customers: 2701
Experience: L1 Advanced Level Diagnostics Specialist
AMD and 8 other Car Specialists are ready to help you

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