charging volts

[motoman358]

i think my alt i taking a crap, the batt and brake/abs (strange?) lights came on the other day and my car got progressively harder to start until it wouldnt start at all. i logged the batt voltage and it is only at 11.95-12.05 while running after a full charge. I just want to make sure that that would be caused by the alternator before i rip it out. if i remember correctly the battery should be at around 13.5ish so i dont think my alt is charging it like it is supposed to. please let me know asap as i would like to fix today. thanks guys!

 

[Mattsteff]

You should be seeing 14v with the car running and everything on, 11.9v is a dead battery believe it or not, a fully charged battery should read around 12.6-12.9v on a good charge. So I would change the alternator as it looks to be the culprit. those lights are usually a dead give away.

 

[motoman358]

thats what i was thinking but wanted to confirm before ripping it apart.

 

[turboglenn]

Yea, start it up, get it warm. Then turn on all your accesories and put a voltmeter on the battery terminals. You should get at LEAST 13.5v ..13.8 - 14.x would be better. Anything higher than 15v also means a failing regulator (which is built in on our alternators)

 

[babell2]

Concider it confirmed Alternator output should be between 13.5V and 15.V Anything higher or lower the Alternator or regulator has taken a dump.

 

[silvreclips]

At night with my lights on I only pull about 11.9v at idle and around 12.5v driving. It seems a little low but it has been like this for a while now and I haven't had any problems. I get 13.5v during the day with the lights off.

 

[turboglenn]

At night with my lights on I only pull about 11.9v at idle and around 12.5v driving. It seems a little low but it has been like this for a while now and I haven't had any problems. I get 13.5v during the day with the lights off.

That's just the early warning signs. It will probably last much longer, but voltage will continue to dwindle untill your tach jumps at idle with all the lights on and what not. Then it will go away when you rev it. That's how i knew my last one took it's final sh1t.

On my laptop while monitoring engine data, i'm starting to see that my latest ALT is starting to give up it's ghost as well. But oh well, it was a used one i got for free 6 years ago and i put it on the car about 3 years ago and it's held up well. There were a lot of perks to working in management at a junkyard...can you say FREE PARTS all over

I got a apexi BOV, greedy turbo timer, short shifter and many other goodies including the 6 bolt blocks that i originlly started building all for no more than 100 bucks (50 bucks for one block and 50 for a head )

 

[babell2]

At night with my lights on I only pull about 11.9v at idle and around 12.5v driving. It seems a little low but it has been like this for a while now and I haven't had any problems. I get 13.5v during the day with the lights off.

I'm glad you have a good battery. You seem to be running on it a lot. Your regulator is not making the Alternator put out enough voltage for a good recharge let alone carrying extra load from lights and amps etc...

 

[silvreclips]

Yea I know, but I dont understand why I haven't had any problems with it. Car runs fine, so untill it starts causing a problem it can just stay in there.

 

[Spades]

Yea I know, but I dont understand why I haven't had any problems with it. Car runs fine, so untill it starts causing a problem it can just stay in there.

You've already confirmed it, if you wait until there are signs of problems you will be adding towing fees to your total expenses