Lights, Music, Wipers - Shut down, Am I overloading the Alternator? Options

[aveale]

Family,

With the wipers on full, the radio cuts out and comes back on, then cuts out (I am assuming when the motor needs more "load" it sucks the power from the radio).

Am I overloading the Alternator???

I have a very small (1985) Blaukpunkt (sp) radio that ain't no boomer.

This can also happen at night when I switch to my high beamers.

Comments/solutions anyone?

T

[Spoke]

I don't think it's your alternator since if the load were to cause the voltage to drop, it should only drop to the battery voltage then the battery takes over.

I would suspect something in the wiring including not-so-good ground or power connections. There is a 12V power lug behind the fuse panel that on my car was not loose but it also was not tight.

If you have an analog voltmeter, attach it such that the wires stay on by themselves (alligator clips), then with the car on or off, try hitting the lights or other loads that cause the radio to hiccup. If something bad is happening to the 12V to the radio, the analog needle will quickly deflect lower then go back to 12-14V. If you have a digital voltmeter, the readout is not quick enough to see the droop. If you don't have a multimeter, buy one.

To check the ground on your radio, with the voltmeter, attach one wire to the battery negative terminal, then with the other wire, attach to the radio chassis and see that you have less than 0.5 to 1V of drop. Should show less. If more than 1V, find the drop by measuring different points on the chassis with respect to the battery negative terminal.

Good Luck,
Spoke

[davep]

Thats correct, you must have a bad connection or two somewhere to cause the radio to cut out.

[SGB]

what about the voltage regulator? What kind of guage readings do you see?

[aveale]

what about the voltage regulator? What kind of guage readings do you see?


--------------------
-Scott


That was my next question. With lights on I am about 11 1/2. During the day I am about 12 1/2.

Could that also be the culprit?

T

[SGB]

Bad VR usually overcharges. I think your alt isn't putting out enough juice, thouge. You should get about 13.5 or so all the time. I actually had a poor charging alternator for years before I figured out it had a dead diode. That 12.5v running will slowly charge the battery. As the power drains, the lights would go dimmer and dimmer, but the radio will just shut off below a certain voltage.

[davep]

If you are going by the console guage, then that is typical. To really measure the voltage use a digital meter right on the battery posts. Measure before starting the car after sitting overnight, measure at idle, and measure while running over 2500 rpm. Just for fun measure at over 2500 rpm and between the positive battery post and the engine fan housing (as the ground). If there is much of a difference between the negative post and the fan housing measurements it usually means that there is a ground circuit problem.