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Discussion Starter #1
During the day my charging system is fine, but at night if I have the blower motor, radio and lights on, there's a significant draw. The radio dims and cuts out, (this always happens to it when there's a low charge) and the power windows are slower than normal so it doesn't seem to keep up that well. My old alternator was a rebuilt Delco unit and it worked fine until one day when it died and I replaced it with an identical unit (part numbers and voltage output are the same), except with a nice used original one (couldn't afford a new one at the time). I also replaced the voltage regulator too, also a used original unit but in very good condition. Both parts look great in appearance and came off relatively low mile cars I was told. Which could it be?
I thought that the alternator could either be good or bad, no in between. Should I try switching regulators (with a new one) and see if that helps? Like I said, it charges fine, but doesn't seem to be putting out enough (or as much as it used to with the old parts when they worked, it kept up just fine then)when there's a big draw. Battery is good too. I don't have a voltage tester as of now, I just go by the symptoms I'm getting. Thanks

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1970 Chevy Custom El Camino
Originally was & will be Green Mist & Silver w/Green Vinyl Top (now black/black)
350ci/300HP 4bbl & Dual Exhaust
TH-350 - 2.73 Posi Rear - Factory PS, PDB, PW, Tilt, A/C & More
Also, check out my new 1987 Chevy Caprice Coupe!
Other Restorations - 1969 Snowco Trailer & 1967 Sears Custom 600 Tractor
 

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I'm not sure what really to suggest if you can't measure things. I guess the best I can come up with is to swap to a newer internal regulated alternator. The car's running so you have some time to look around and find a nice one in the junkyard. Take the alternator connector when you grab the alternator. You will need it for the swap. This, at least does three things, replaces the alternator, replaces the regulator, and gets you more available current out of the alternator. One of those three things should help.
 

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Some free things to try.[Based on a 1964]
Look for dirty, loose, or corroded connections at the alternator, and the main power feed from the battery to the horn relay. Check grounds from battery to body, especially;engine to firewall, batt negative cable. Check firewall connectors.It sounds to me like a bad connection somewhere which is limiting current flow.
PS: you can also check your fuses for clean and tight connection.
If all connections are good, probably your voltage regulator.
Some auto parts stores can check your charging system free - call around.

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It's possible the operating voltage of that new regulator is lower than the old one. That could be making the voltage appear low. They can be adjusted by moving the double sided contacts closer to the coil. It doesn't take much but keep the distance between them the same and use a good digital meter to measure the operating voltage.

Running all those accessories is asking a lot of that charging system. It will not keep up at idle or low engine RPM's with that load.

Peter
 

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Discussion Starter #5
Thanks for the help, I'll check into that, switching the regulator and the wiring. I know it's a bit hacked up, that might be the problem. Is it possible for an alternator to only work halfway? I thought they could either charge or nothing at all.

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1970 Chevy Custom El Camino
Originally was & will be Green Mist & Silver w/Green Vinyl Top (now black/black)
350ci/300HP 4bbl & Dual Exhaust
TH-350 - 2.73 Posi Rear - Factory PS, PDB, PW, Tilt, A/C & More
Also, check out my new 1987 Chevy Caprice Coupe!
Other Restorations - 1969 Snowco Trailer & 1967 Sears Custom 600 Tractor
 

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<BLOCKQUOTE>quote:</font><HR>Originally posted by Shawn:
Is it possible for an alternator to only work halfway? I thought they could either charge or nothing at all.
<HR></BLOCKQUOTE>

Not halfway but as Peter said, maybe the voltage is on the low side. If the voltage is not high enough, it does a poor job of charging the battery. If it is too high it tries to overcharge the battery.
 
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