I just disconnected my car battery negetaive cable while running. the car continued to run. Contrary to one an?

Cars have their batteries wired in parallel to the electrical system, not in series with it. Most cars will continue to run even with the battery disconnected. (Some engine electronics will detect a disconnected battery and shut down, but that's due to their programming, not to how the battery is wired.)

Despite what someone else has said, disconnecting the battery does not cause the mean voltage in the system to increase and you are not in any way "sending 14 volts through electronics designed for 12". Sensitive electronics are all protected by voltage regulators that will maintain proper voltage levels (interesting fact: many parts of a car's electrical system run at less than 12 volts, relying upon voltage regulators to drop the voltage).

Also, a car's electrical system is not designed for 12 volts nominal. Most automotive electrical systems are designed to operate at 13.4 volts nominal. In fact the lumen output specs for headlight bulbs stipulate the design voltage as 13.4 volts as this is the nominal output voltage for the alternator in order to provide adequate float charge to the battery.

That said, removing the battery while the engine is running is not recommended for modern vehicles as the battery does play an important role in surge suppression by absorbing current spikes and if you run a vehicle without a battery for an extended period of time you put extra strain on the voltage regulators within the vehicle's electrical system. In older vehicles that used carburetors and did not have computer controls removing the battery was fine, but it's generally not recommended for modern cars.

The reason is that as you have started your car and the battery simultaneously has charged the electromagnets in the alternator that create the magnetic fields in the alternator it is then able to energise itself and keep the power going, by the way many, if not most modern alternators have voltage regulators build in, if yours don`t you may damage things by running too high a voltage.

Old type generators with permanent magnets did not need a battery to supply power before they were able to produce electricity.

Now in your case you may also get some problems with your cars electronic`s if you switch your engine off while the battery is disconnected, but you have most likely figured that out by now.

I would have thought the car would continue running? The battery is used to start the car, but once it is running, then the alternator is charging the battery and running all the car's electrics.

The battery being disconnected will prevent it from charging, but the whole bodywork will still act as the negative, as it is connected to the negative of the battery charging network.

I'm glad you brought this up, as I missed the original question and it would have made me think I was missing something as I would not have agreed with the answer...

Not a good idea. The volts can go too high and burn stuff out. At least, that's what happened on my boat when a kid turned off the main battery switch with the engine running and it burned out my radio. The ignition etc. was OK though - old non-electronic type, no computer.

Not good to do that, can damage electronics. The battery acts like a giant capacitor to dampen voltage spikes generated by the alternator.

it means your car is getting it,s juice from the alternator. i would,nt be doing that especially with these newer cars or you have a chance of burning up the computer.

the alternator is providing power...not a good idea..you may have 14 v running in electronics built for 12.

When the car is running ,it runs off the altinator not the battery.

So as long as your altinator is good It will stay running.

means ur alternator is good! car can still run without battery as long as ur alternator works! but for a good 5-10 minutes

p/s car battery charges the alternator while it runs

Wow, thank you! I was asking myself the same thing today