alternator question
10-27-2007, 05:45 PM
#1
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alternator question
I have a 69 coupe with a 302. With the headlights on and the engine at idle the radio turns off momentarly when the turn signals are activated. My stereo system has an amp. Could the stock alternator not be up to the task? I've been looking at 100 to 130 amp single wire alternators. Is there an advantage to the single wire? From what I've read my amp meter will no longer work with the single wire. If so is there a way around that? Thanks
10-27-2007, 05:47 PM
#2
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RE: alternator question
What's your idle speed? There are a couple options. The first would be a rebuild of the alternator you have, and the second would be a different size pulley (smaller) on the alternator.
What size is the amp? It'd take quite a bit to overload the stock alternator with most single amps.
What size is the amp? It'd take quite a bit to overload the stock alternator with most single amps.
10-27-2007, 07:12 PM
#4
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RE: alternator question
It's typical for other accessories in your car to lose power when you turn on the turn signals at a stop and your car is at just an idle. Especially if you have a low idle, which Colorado alluded to above. I have an aftermarket voltmeter and I can watch the needle ping back and forth in sync with the turn signals when I'm at a stop, especially at night with the lights on. One thing you can check that wasn't mentioned above is your belt tension. There should be no more than 1/2" of movement up and down when checked at the midpoint between the alt and water pump pulleys. Mine was loose at one point and wasn't charging the battery enough. If I were you, I'd go ahead and use opportunity as an excuse to upgrade to a 100-amp alt. I'm always looking for something to justify another project on the Mustang. My wife doesn't know any better, so I can usually get away with it. haha
10-27-2007, 10:38 PM
#6
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RE: alternator question
ORIGINAL: smittycm
It's typical for other accessories in your car to lose power when you turn on the turn signals at a stop and your car is at just an idle. Especially if you have a low idle, which Colorado alluded to above. I have an aftermarket voltmeter and I can watch the needle ping back and forth in sync with the turn signals when I'm at a stop, especially at night with the lights on. One thing you can check that wasn't mentioned above is your belt tension. There should be no more than 1/2" of movement up and down when checked at the midpoint between the alt and water pump pulleys. Mine was loose at one point and wasn't charging the battery enough. If I were you, I'd go ahead and use opportunity as an excuse to upgrade to a 100-amp alt. I'm always looking for something to justify another project on the Mustang. My wife doesn't know any better, so I can usually get away with it. haha
It's typical for other accessories in your car to lose power when you turn on the turn signals at a stop and your car is at just an idle. Especially if you have a low idle, which Colorado alluded to above. I have an aftermarket voltmeter and I can watch the needle ping back and forth in sync with the turn signals when I'm at a stop, especially at night with the lights on. One thing you can check that wasn't mentioned above is your belt tension. There should be no more than 1/2" of movement up and down when checked at the midpoint between the alt and water pump pulleys. Mine was loose at one point and wasn't charging the battery enough. If I were you, I'd go ahead and use opportunity as an excuse to upgrade to a 100-amp alt. I'm always looking for something to justify another project on the Mustang. My wife doesn't know any better, so I can usually get away with it. haha
10-28-2007, 06:37 AM
#7
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RE: alternator question
I would check my grounds for the headlights and turn signals. Sounds like it could be a feed thru issue (loose ground). Also you can change out the flashers (thermal) for solid state units. These work much better and are not effected so much by voltage drops. Do you have the radio and amp hooked to the battery or into the original wiring harness (thats a no, no)? Is it a good battery? If you choose a larger alternator, you will need to increase the wire size to the battery and ground to handle the extra amps.If you use the single wire alternator, youwill notneed the regulator as most these are internally regulated. I would install a volt gauge to monitor theelectrical system. If the volts are down, the amps are up. If the alternator is maxed out when everything is on, the volts will drop alsoas the alternator can not supply enough amps to push the volts thru. A 1000 watt amp will draw about 72 amps on a fully charged battery (13.8 volts) under the maxium load (1000 watts). If the battery is little weak (12 volts) it will draw 83 amps. I would guess the headlights and tail lights pull about 15 amps with the original bulbs (halogen about 5 more amps). When the turn signals are on, (with a thermal flasher), add another 5 or10 amps. Anyway, keep in mind that when the volts are down, the amps are up. Oh, I just noticed your amp is 250 watts, thats about 20 amps draw (full load). Hope this helps.
10-28-2007, 12:55 PM
#8
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RE: alternator question
A 250w amp isn't an overload for the factory alternator. I suspect the alternator iseither weak and needs rebuilt or the voltage regulator isn't up the task. I have had VR's make it seem like the alternator wasn't putting out enough, even though it was the VR dropping the power output.
