Voltage drop question

[IonRL205 10+ year member]

Ok well I put a new yellowtop optima in my car yesterday and i tested my system with it and at idle with the system blasting my voltage didn't drop below 13.3v

Well as I was driving home today, I noticed my lights started dimming. I checked the voltage and now it drops to 12.6v with the same song I used. I've never had problems with dimming before. Question is did I get this decrease in voltage due to have been using the battery some, or could a loose wire somewhere cause this voltage drop, or maybe a defective battery?

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[keep_hope_alive Premium Member]

what vehicle? Honda/Acura have an ELD that will turn off the alt.

loose grounds will increase resistance. voltage is relative, so grounds should be very tight and clean (no corrosion).

are you charging the battery properly? running at full tilt all of the time can prevent the battery from ever charging.

 

[Sleeklsc 5,000+ posts]

nm

 

[Whattha 10+ year member]

Did you have the headlights on with the initial testing you did? You gotta remember your battery is gonna charge everything and if your headlights wasnt on in the first test you did but was on when you was driving home that could be your culprit bud.

 

[IonRL205 10+ year member]

Turns out to be a bad battery...tried to go out to start my car and it wouldn't start. Checked the voltage on the battery, and it was only 10.7. This is the 3rd one in like 4 months to happen! I got this battery Monday and it already crapped out on me...I know it's not my system doing anything, just a bad batch of batteries I guess :/ glad about the 3 year warranty though lol

 

[LosIsATool 5,000+ posts]

Did you charge it before installing?

 

[subzero 5,000+ posts]

I doubt you have that luck to get all bad batts. sounds like you got a system drain. or your charging is not adequate to sustain the batts and charge at the same time. what is the alt amperage. what amperage is your system pulling?

 

[IonRL205 10+ year member]

I have a 140 amp alternator and 2 gauge wiring around. And the voltage doesn't drop below 13v with the system playing and I've never had light dimming problems. The battery I had before lasted about 2 months and then a cell went bad, and this one lasted a day.

 

[sexy 10+ year member]

It could be that whoever you are buying them from is selling outdated yellow tops. Optima pulls their batteries out of the stores after a certain amount time to prevent problems. Check the manufactures dating on the ones you are getting.

 

[sacsking916 5,000+ posts]

You got a short bro. It's not the batteries fault you keep killing them.

 

[jco1385 5,000+ posts]

i have a g31 YT on my porch thats sitting at 13-14v and hasn't moved in 2 years. i will 2nd the short somewhere. no way you got 4 in a row that are bad unless it was a bad batch from the mfgr

 

[09civic 5,000+ posts]

hopefully your alt isnt fried //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

 

[TheUnderFighter 10+ year member]

Sounds like you've got bigger problems than bad luck bro:\