QuestionQUESTION: is there a simple way to test a generator on a 1960
chevy to see if if it is putting out like it should
i've heard you can start engine...disconect battery cable.if engine still runs generator is good ...if it stops generator is bad......???????? is this a good test
ANSWER: Hi Ronnie:
Yes. Use a voltage meter attach it to the positive lead on the generator and it will give you amount of voltage coming from the generator. Also attach the voltage meter to the positive lead on the regulator output to the battery to make sure your problem isn't there.
However, disconnecting the battery, all that will do is stop your electrical system. An engine is a mechanical device, not a electrical device. As long as the engine is running, it will remain running. The battery is only needed to turn the starter to start an engine.
Now, let's talk about the old fashion way to test a generator. The best way to tell if you generator is good (e.g. charging) is to let it run with all the auxiliary devices on (e.g., headlights, radio, air condition, etc.). If the generator is bad, the battery will eventually go dead due to lack of charging. These devices get their current directly from the battery and the battery get its current directly from the generator.
Keep in mind, that generator will create more current at a higher idle speed to help charge the battery faster. So, if you get a generator light at idle, it does mean the generator is bad, but could mean either your idle speed is too low or your fan belt is loose and slipping.
Also, the voltage regulator controls the amount of current passing to the battery from the generator and it could be bad (e.g. not supplying enough current to keep the battery charged).
And, finally, the generator and regulator could both be working fine, but the battery has a dead cell and will not hold a charge. So, you really have to check all of these things to pinpoint the actual problem.
Hope this helps.
---------- FOLLOW-UP ----------
QUESTION: OK...EVERYTHING YOU SAY MAKES SENSE...BUT HOW COME WHEN THE
MOTOR IS RUNNING...& I DISCONNECT THE BATTERY THE ENGINE DIES
IF WHAT YOU SAY IS TRUE ABOUT THE BATTERY BEING JUST TO START
THE ENGINE....WHY DOES THE ENGINE DIE WHEN BATTERY CABLE IS
DISCONNECTED????
AnswerHi Ronnie:
It is clear to me that your car has been rewired to draw current directly from the battery. This was an old trick years ago to temporarily get around a bad generator. If you have more than two wires coming from the battery, then I'm right. Your car has been wired directly from the battery to either the ignition or the generator because one of them had gone bad. However, if you only have two wires coming from the battery, and the positive cable is connected to the starter and the ground cable is connected to the chassis, then there is no way the car should stop running with these cables disconnected from the battery. All power should be coming from electricity created by the generator and fed to all electrical systems in your car.
Newer, more computerized cars have lot of monitoring sensors that works while the car is parked. Such as anti-theft sensors that draw a small amount of amps from the battery, but not enough to run it down.
