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gmrulz4u

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OK, I'm going to go into a lot of detail, to make things easier...

First, my car is a 1989 Olds Cutlass Supreme 2.8L.

Secondly, I have a very expensive stereo ie. 3 amps, 8 speakers, 4 subs, etc..etc...

 

I replaced my battery with an Optima Red Top about 1 year ago. At the same time, I changed my alternator to a high-output 140 amp alt., plus I changed the power and ground wire to a thicker gauge wire. I guess I shouldn't say "I changed...", I should say "I had them changed...", because shops did it all, not me personally.

 

When the weather is nice and hot, with the sun beating down, my voltage is just awsome! I have a digital voltmeter that I've tested to be 99% accurate. Sometimes my voltage is at like 16 volts or higher, never over 17, and even at slow idle, I would get over 13 volts! Of course, all these readings are when it's nice and hot out.

 

Now for the bad part. When it's NOT above 80 degrees, my voltage reading sucks! These days(cold days), when I'm driving, even with my stereo off, I'm getting 11.5 volts at idle, with my heat on, 10.8-11.2!! And this is with my stereo off!!

 

My RPMs at idle are around 700.

 

The thing that makes this so strange, is the fact that the outside temperature makes such a HUGE difference in my voltage reading!!?? And I thought that HOT alternators are supposed to give out LESS power??

 

I have noticed that when I get up in the morning, and it's pretty cold, anywhere from 30-50 degrees, my batteries voltage is sometimes only like 10.8! BUT, what is strange, is that the car starts perfectly??

 

Anyone have any idea as to what the heck is going on here??

 

THANKS:o)

PS I do notice at night sometimes that my lights do dim and then get bright when the RPM's increase...

It's so annoying when I have the heat on, and the fans slow down as the RPMs slow down, and speed up as the engine RMPs go up!!

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Sounds like a battery problem. Batteries are supposed to produce less power when cold than when hot. That's why they are rated in CCA (Cold Cranking Amps). It's also why in winter, some people's cars won't start.

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In the winter the amperage that the battery will output will be less than compared to when the ewather is warmer. Occording to my friend, Ohm's Law states that V = RI, where v = voltage, r = resistance, and i = current. So less current = less volatge, and r is a constant.

 

Paul

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I say don't worry about. its normal your battery and ALL batterys are measured in Amps and Cold Cranking amps. My Yellow top was only $130 from my buddies shop. normally go for about $200. it has i believe 850amps and 650CCamps. they Yellow top is generally the one you want for a sterio anyways.. Deep cycle won't drain from running your sterio.

 

RedZ

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