Can vehicle run without battery?

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I had to jump my father's E-150 today. We got into an argument about the battery. He says you can run a car without the battery and while running, the alternator alone can run lights, radio, etc. I told hime no, the alternator charges the battery and the accesories are run off the battery.

Who is correct? Thanks.
 
Once you manage to get your car/vehicle started by using a storage battery, the engine should keep the alternator running to the point where it(the alternator itself) shall be able to provide enough power to keep itself running.

in other words: once you successfully turn over your engine and fired up, the alternator itself should be capable of taking over the task of supplying enough electricity to keep the engine running (ignition module(s), computer control, etc.) and you shall be able to undo the battery from that point onwards to prove his point.

Q.
 
p.s. all other onboard/electrical accessories run off of the same power source (alternator) where it charges the battery + ignitions+ all the accessories combined. Battery only serve for the sake of turning over the starter motor while still provide enough juice for all the computer controls + ignition controls.
 
Semantics... It won't start without a power source of some sort, and it won't run for long without an alternator.

Most spark ignition powered vehicles will run without the battery connected, but doing so can result in electrical surges that are not good for the electrical items.
 
It depends on the vehicle. Some only use the battery to power the starter and from there on it's just along for the ride. Others, especially newer ones use the battery as a reference voltage and require it to be in circuit for the car to operate properly. For example, I know for a fact that I can start my 2003 Taurus just fine off jumper cables with no battery. It will even sit there and idle and you can put it in gear and start to drive off but at about 15MPH it dies. I had a dead cell in my battery and I was doing everything I could to just get over to the parts store.
 
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In some cars the alternator is, under some conditions and especially at idle, not capable of supplying the full electrical demands of the vehicle.
 
The battery provides some level of protection in the rest of the electrical system from surges and drops. It would run but I can't really recommend it. Depending on the car's wiring, it may not work without the battery.
 
I call it a draw. My father used to have a motorcycle in the '70s that could run off the magneto only with no battery. Thanks for the replies.

BTW I started my ranger, pulled the neg cable off and the vehicle continued to run. Turned the lights on, and she shut off.
 
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+1.
An old-school shade tree method of determining whether your problem was with the alternator or the battery was to start the engine and then disconect the negative cable from the batt.
If the thing continued running, and everything functioned with the lights on (horn, turn signals; high draw items IOW), then your problem was the batt. If the thing died at once, your problem was the alternator.
I have always though that disconecting the battery from a running vehicle was a bad idea.
There are VOMs for a reason, and a simple one is pretty cheap, and has a host of uses.
 
I would say you need the battery in all newer vehicles. The alternator runs 13.5 volts to the battery which then sends out a stable amount of electricity to feed everything, I think unhooking a battery would "hopefully" blow out a fuse for the computer and all the electronics, if not it would fry alot of stuff by force feeding it high unregulated voltage. I started a Polaris atv without a battery and it blew every light bulb, because the battery was removed to stop the unwanted voltage. Bad idea. Cars can run without the alternator, and alot of stock car drivers take off the belts to get more power and just charge the battery after the race for the next start.
 
No.

A battery is an integral part of the electrical system.

Removing the bat from the system when running will damage or destroy components.
 
There are milliseconds between diodes in the rectifier when zero current is being produced. One would be relying on the filtering capacitors in the radio etc to backfeed the rest of the car's electricity during that time.

In "ice road truckers" they were doing a routine inspection on an always-idling truck and discovered the batteries fell out and were somewhere on the tundra...

My old mercedes diesel would have run without any electricity at all, roll started, if it had a long enough run to build up heat without glow plugs. Popular escape vehicle for the EMP fearing crowd...
 
Depends on the car. Some with run with no battery, some will not. Some cars will run without a battery connected and when you reconnect it the car will shut off.

(It's better and safer to run the car the way it is designed of course.)

I call it a draw on the discussion. Technically the alternator is all that is needed to run the car (once it is running).
 
Originally Posted By: highmilegeguy
No.

A battery is an integral part of the electrical system.

Removing the bat from the system when running will damage or destroy components.



So if your battery Dies because of an internal break??
(as happens on occasion)
 
Originally Posted By: beast3300
Depends on the car. Some with run with no battery, some will not.
Yup most cars wont run. It's a safety thing to prevent sending voltage spikes to the computer.

A 69 Chevy pickup will run w/o a battery. A 99 Chevy wont.
 
I subscribe to the theory that all power is supplied by the battery and that the alt merely replaces it.


The battery would act as a capacitor. I'd say that any marginal storage medium (a shot battery = capable of just temporarily holding a charge) would work good enough.
 
Both right and wrong.

A car cannot reliably run on the alternator alone. The battery cleans the power like a capacitor and puts out during bursts only to be immediately refilled when the alternator catches up. Without a battery a sudden load from the headlights or the heater fan will kill the engine all the while you may be destroying electronics with the dirty power. Old cars with few electronics and low power usage would tolerate an alternator without a battery but new cars require a lot of electrical power that must be clean so are unlikely to run at all.

However when running all things run off the alternator, not the battery.

A car with audio stiffening capacitors would probably run as well with or without a battery. The handful of small capacitors in various vehicle electronics aren't enough.

Magneto engines are usually designed to run without power. That doesn't prove that coil spark engines can also.

Originally Posted By: eljefino
There are milliseconds between diodes in the rectifier when zero current is being produced.

Maybe in single phase power but an alternator is 3 or 4 phase power. The waveform is bouncy but there is always current.

Originally Posted By: Gary Allan
I subscribe to the theory that all power is supplied by the battery and that the alt merely replaces it.

Any ammeter will prove this theory. My meters always say current is going into the battery.
 
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