Battery voltage 11.9 - 12.0, car still starts? WTF?

[Sir Swish 10+ year member]

My battery is reading at 11.9 - 12.0 which is completely dead and my car still starts fine. When the car is running my voltage is in the low 13s with no music playing. I checked my gfs car and her voltage reads normal so I know its not the DMM. What in the hell is going on? I had starter problems a while back but that wouldn't cause a huge voltage drop like that would it? Bad alt? HELP!!!

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[*SlappinAzz*]

My battery is reading at 11.9 - 12.0 which is completely dead and my car still starts fine. When the car is running my voltage is in the low 13s with no music playing. I checked my gfs car and her voltage reads normal so I know its not the DMM. What in the hell is going on? I had starter problems a while back but that wouldn't cause a huge voltage drop like that would it? Bad alt? HELP!!!

Sounds like your alt is giving way, question, did you do the big 3, and if so, what size alt do you have?

 

[Sir Swish 10+ year member]

Sounds like your alt is giving way, question, did you do the big 3, and if so, what size alt do you have?

I did the Big 3 in 2/0 gauge. All wires soldered, connections nice and tight. I just added on to factory wire (didn't take anything out). Stock 130 amp alternator. I have 220 amp sitting around.

 

[*SlappinAzz*]

I did the Big 3 in 2/0 gauge. All wires soldered, connections nice and tight. I just added on to factory wire (didn't take anything out). Stock 130 amp alternator. I have 220 amp sitting around.

Really sounds like the alt to me, but you may want someone with more experience to tell you.

 

[Jaredturp 10+ year member]

My voltage is around there all day every day. Music or not.

 

[Blasphemy 10+ year member]

How old is the battery? They go bad after awhile.

 

[Sir Swish 10+ year member]

How old is the battery? They go bad after awhile.

Not very old at all.

 

[05fronty 5,000+ posts]

i would take your car down to a local advanced,auto zone, etc and get it tested. the ones around here test for free

 

[Sir Swish 10+ year member]

now battery voltage is down to 11.6 and the car still starts fine without any problems. WTF?!?!?!?

 

[PrestigeSounds 10+ year member]

any extra batteries? you've got the 220 laying around why not slap that thing in there?

 

[Sir Swish 10+ year member]

any extra batteries? you've got the 220 laying around why not slap that thing in there?

I have my stock battery. It is resting at 12.4 volts. I could throw that in there. I don't want to put my 220 amp alternator because I don't know what is causing such massive voltage drops. Battery light is not on and lights don't dim at all. WTF. lol

 

[Slo_Ride 5,000+ posts]

Wow thats definitely strange. without being there its hard to say, but as long as it still starts all is good. I doubt its the alternator. Like mentioned before take it to your local parts store and have them check the battery and everything just to see what they come up with.

 

[PrestigeSounds 10+ year member]

a wise man once said...."leave well enough alone"

 

[Sir Swish 10+ year member]

Wow thats definitely strange. without being there its hard to say, but as long as it still starts all is good. I doubt its the alternator. Like mentioned before take it to your local parts store and have them check the battery and everything just to see what they come up with.

I just had the battery checked last week at Autozone. They said it was fine. It is a marine battery but they said it makes no difference. I'm totally amazed my car is still starting with 11.6 volts in the battery. I did everything right. Big 3 done with 2/0 gauge, lead free soldered, grounds sanded, stock wires left alone, pure cooper terminals, etc.

 

[Sir Swish 10+ year member]

Like seriously guys, I'm completely in shock right now. Is this even possible?