Xxyyzz Posted January 2, 2013 Share Posted January 2, 2013 My headlight actually don't dim, they get brighter when I give it gas. Is this normal for an older electrical system or is something wrong? If something is wrong how do I troubleshoot it? If it is normal is there anything I can do to minimize it? Alternator replaced recently. Large sound system in car. -Mark Quote Link to comment Share on other sites More sharing options...
wallaby Posted January 2, 2013 Share Posted January 2, 2013 Have you switched to a different style alternator? Sometimes the internal regulated type aren't as good at low speed charging. The other concern is where the power feed for your amp is hooked up. Is it connected direct to the battery? It might behave better if it's hooked up at the buss bar near the drivers side headlight. maybe speed up the idle a bit? Quote Link to comment Share on other sites More sharing options...
MGD72Monte Posted January 2, 2013 Share Posted January 2, 2013 Check your idle speed for spec and what voltage you are getting at idle. Sounds like the alternator is not turning fast enough to get you up into the 14.5V range when at idle. Quote Link to comment Share on other sites More sharing options...
stangeba Posted January 2, 2013 Share Posted January 2, 2013 My 71 is all stock, 350 4BBL automatic NO A/C with the original small 35 Amp alternator that I rebuilt and a stock regulator, with a full gauge package, all wired up just like the factory. When my lights are on and it is idling in gear, they do dim some and I believe the have for many many years. The AMP gauge goes into the (-) range a bit also. I DON'T remember this happening back in 1971. (I think) If my memory is correct (I can't find documentation) in 70 - 72 the standard battery was not maintenance free and we all remember added distilled water to the battery every once in a while. Today we use mostly batteries with out fill caps. I thought I remember that to make them maintenance free, some sort of internal ?resistor? or something was added so the batteries could not be overcharged and boil out the water like OEM batteries from 70 - 72 could. Could THIS add to the dim lights at idle issue? Just thinking out loud here, any thoughts? Bruce Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted January 3, 2013 Share Posted January 3, 2013 aftermarket pulleys can effect your alt at idle too, a smaller crank pulley slows the alt and waterpump Quote Link to comment Share on other sites More sharing options...
502ci Posted January 3, 2013 Share Posted January 3, 2013 Ditto to the above answers. You mention the alternator has been replaced, my aftermarket Powermaster alternator needs to be revved/excited to actually kick on or my accessories are running on the battery until I do so and the headlights will be dim. Your replacement alternator also may need a smaller pulley to speed it up. Quote Link to comment Share on other sites More sharing options...
stangeba Posted January 3, 2013 Share Posted January 3, 2013 Anyone know if Halogen headlights draw more power than stock 1971 style seal beams? I put in Halogens years ago and forgot about it. Bruce Quote Link to comment Share on other sites More sharing options...
Xxyyzz Posted January 3, 2013 Author Share Posted January 3, 2013 I will definitely be raising my idle speed. How can I measure the RPM's without a tach? The alternator is an internal regulated type. My voltmeter tells me its around 14 point something during charging. What is a stock pulley diameter? I'll have to measure mine. I'm curious about different bulbs drawing less power. Maybe I can upgrade. -Mark Quote Link to comment Share on other sites More sharing options...
snomobeelr Posted January 3, 2013 Share Posted January 3, 2013 From what I have read if this site is correct it is actually the electrical system in our cars. Check it out http://www.madelectrical.com/electricaltech/brighter-headlights.shtml Quote Link to comment Share on other sites More sharing options...
Xxyyzz Posted January 5, 2013 Author Share Posted January 5, 2013 oh, wow! has anyone here fixed the issue on thier car? Quote Link to comment Share on other sites More sharing options...
stangeba Posted January 5, 2013 Share Posted January 5, 2013 I don't drive at night much, so I don't think about it. Fixed good enough for me! Bruce Quote Link to comment Share on other sites More sharing options...
wallaby Posted January 5, 2013 Share Posted January 5, 2013 I did the 8ga alternator to buss-bar upgrade, with good result. I have electric fans and wanted to make sure everything from the alternator was getting to that buss. I have NOT converted to the relay system for my headlights; those seem plenty bright to me. I have thought about it though...I like the idea of gaining power for the dash lights and ignition circuits. Quote Link to comment Share on other sites More sharing options...
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