Voltage drops all of a sudden?

[I Like Waffle]

I just did a new install with an alpine m500, which i would guess is around 550-600wrms, and at night i get bad voltage drops with it. Sometimes down to like 11.9 //content.invisioncic.com/y282845/emoticons/eek.gif.771b7a90cf45cabdc554ff1121c21c4a.gif Ive ran more power than this before and never dropped below 13.5, but now all of a sudden it is? Ive got the big 3 done except for the ground wire to the engine (its 4 gauge, but the old school kind). Basically i can get another 110amp alt, or another battery, for roughly the same price. I have a bracket for another alt, so what would you guys do? What are the pros and cons of each?

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[jdawg 5,000+ posts]

how old is the alt and batt now?

 

[loopkiller 10+ year member]

Battery closer to the amps would help. IMO an HC800.

 

[I Like Waffle]

Loose alt belt ftmfw! Had about 2 inches of play in it, and one of my grounds was slightly rusty. I changed out the last ground (the factory one was actually high strand 4 gauge) //content.invisioncic.com/y282845/emoticons/eek.gif.771b7a90cf45cabdc554ff1121c21c4a.gif Dont think that made much of a diff but either way now im getting 15.2 at idle at the alty, and 14.4-14.9 at the amp even when its wide open //content.invisioncic.com/y282845/emoticons/cool.gif.3bcaf8f141236c00f8044d07150e34f7.gif

 

[DDSC 10+ year member]

no extra batts, what vechile and size alt please????

 

[I Like Waffle]

car in sig, factory 110amp alt, everlast walmart battery (930 cca) rockford 4g to amp and on big 3. Id say im pulling about 900-1k rms all together and basically no voltage drops so far //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif Id say its cause my car is old and has basically nothing electronic besides the lights and whatnot. My brothers car is even older and sometimes his voltage at the AMP will read up to 15.8 at idle //content.invisioncic.com/y282845/emoticons/eek.gif.771b7a90cf45cabdc554ff1121c21c4a.gif Using a 40$ craftsman DMM btw.

 

[DammitJames 10+ year member]

if u have power problems when ur car is running its always going to be something with the alt or wiring batter does nothing when the car is running except stablize voltage or handle demands the alt cant in ur case the alt should have handled that much with ease

 

[jdawg 5,000+ posts]

if u have power problems when ur car is running its always going to be something with the alt or wiring batter does nothing when the car is running except stablize voltage or handle demands the alt cant in ur case the alt should have handled that much with ease

not true, if a battery has a shorted cell then it can put a bad draw on the alt

 

[DammitJames 10+ year member]

not true, if a battery has a shorted cell then it can put a bad draw on the alt

if the bat had a shorted cell then the alt for be overcharging it making it have more than enough amperage to keep the voltage up on ur amp but yes it will make your alt overwork and therefore possibly hurting ur alt