unclevinny
Member
what is wrong in my starter/electric system to allow the engine to remain running with batter competly disconnected it will kill with the key battery cables seem to be too warm too
58 ford 332 fe runs with battery disconneted
- Thread starter unclevinny
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CrownVic55
Senior Member
Running off of the generator. Normal operation
Crankster
Well-known member
The battery is really only to start the engine technically speaking, the current for the lights, ignition, and accessories is provided by the generator or alternator.
The battery does act as a "flywheel" of sorts, smoothing out spikes or sags from the pulsed DC output. It is true that a generator charging system employs a cutout in the regulator to prevent the battery from backfeeding into the generator windings at low RPM or at shutdown. In low RPM situations where the cutout is open, the battery does carry the entire vehicle electrical load. Alternators employ a diode pack and work much better at low RPM. (And high RPM for that matter)
The battery does act as a "flywheel" of sorts, smoothing out spikes or sags from the pulsed DC output. It is true that a generator charging system employs a cutout in the regulator to prevent the battery from backfeeding into the generator windings at low RPM or at shutdown. In low RPM situations where the cutout is open, the battery does carry the entire vehicle electrical load. Alternators employ a diode pack and work much better at low RPM. (And high RPM for that matter)
KULTULZ
Well-known member
Years ago, in a GALAXIE far, far away ... 
The system was diagnosed with a carbon pile load tester. Back then, parts weren't replaced, they were rebuilt on the bench.
You can now buy hand-held devices that will analyze a charging/starting system.
If the BAT is not up to snuff, you are chasing your tale.
The system was diagnosed with a carbon pile load tester. Back then, parts weren't replaced, they were rebuilt on the bench.
You can now buy hand-held devices that will analyze a charging/starting system.
If the BAT is not up to snuff, you are chasing your tale.
JSeery
Member Emeritus
I've heard that many times. In my boating days we would often take the battery out of the vehicle used to back the boat down the ramp. Then install the battery in to boat to start it and running it on. Because the tow vehicle was still running you could then park it and turn it off. Then reversed the process to load the boat on the trailer. Never any issues with either the boat or vehicle electrical systems. This was in the 70s (73 Ford with 400 & 307 Chevy boat engine), wouldn't try it with newer vehicles with increased electronics!
Daves55Sedan
Well-known member
It is normal for the engine to keep running after the battery is disconnected (at least for a car that has a generator, not sure if same is true for alternators, but I would suspect so). The generator is supplying the current for the spark plugs.
These old jalopies that have an idiot light for the charging system, where sometimes that light stays on (making you think that the generator is not charging), disconnecting the battery while engine running is a fair test to determine if the idiot light isn't lying to you.
If the engine still runs, the generator is at least working, but the charge indicator light circuit may have a problem. Still a good idea to check out the system using a few simple tests offered in the shop manual.
These old jalopies that have an idiot light for the charging system, where sometimes that light stays on (making you think that the generator is not charging), disconnecting the battery while engine running is a fair test to determine if the idiot light isn't lying to you.
If the engine still runs, the generator is at least working, but the charge indicator light circuit may have a problem. Still a good idea to check out the system using a few simple tests offered in the shop manual.