help me determine why my battery won't charge...long

[UW95GST]

I ran a multimeter on the battery and get a 11.xx volt reading. If I leave the engine running it will slowly drain.

I removed the alternator and had it tested, it puts out about 14.xx volts.

When I hook a multimeter up to the alt in the car, black probe to the block and the red probe to the alternator's positive bolt I get 4.xx volts.

I cleaned the battery posts, and checked the tension on the pulley. I'm not sure what else I should be looking for.

Anybody have ideas? Also, does anybody have a electrical diagram showing what connects to the alt and it's connections so I can check for a misplaced wire?

 

[UW95GST]

anybody have any ideas?

 

[gringoloco]

How old is your battery? What brand is it? What type of sound system do you have installed? If its an older battery 1 1/2 years old it could have an open cell. Open cells cause the battery to drain. I would swap it out with another battery and see what happens.

 

[UW95GST]

How old is your battery? What brand is it? What type of sound system do you have installed? If its an older battery 1 1/2 years old it could have an open cell. Open cells cause the battery to drain. I would swap it out with another battery and see what happens.

It's a NAPA, maybe a year or so old.

Even if the battery is old, it should still be getting about 13-14V when the alt is running. Regardless if it holds the charge, right?

I have an amp installed, but I doubt that's the cause of the problem.

Also, the battery light sometimes lights up now in the cabin. And, I'll turn the heater/AC fan on and it won't kick in for until a few minutes later. This only happens occasionally.

 

[gringoloco]

Charge the battery to its full potenial, see if it will charge full. Should read with an ohm meter off the car (or nothing plugged into it) around 12.7 or so. If its not charging fully its your battery (open cell, dead cell, the plates inside, etc) is bad. The battery test while the car is running isnt really a battery test, its to test the alternator to make sure the voltage regualator is working properly. Should read around 14, and no higher than 14. If they test low or high than your alternator is bad. And yes an amp can drain down a battery. Your stock system is what the battery is designed to maintain. So adding extra compents to run off the battery will cause it to drain more quickly (resulting in your battery life being not as long). Also you have had the battery for a year, it could of been sitting on a shelf at a store, etc for a year or so. So you could have a battery that is 2 years old or more. Check your ground wire on your car and make sure its connected tight. But I really think you need a new battery. Bad batteries tend to act up when its cold out because it takes more cranking amps to start the car. Like I said charge the battery and test the battery without being connected to the car, and see what it reads.

 

[spendone]

I say just go to pep boy orautozone to get it checked. Plus even if they tell you its good there should be a full charge on it.

 

[UW95GST]

Charge the battery to its full potenial, see if it will charge full. Should read with an ohm meter off the car (or nothing plugged into it) around 12.7 or so. If its not charging fully its your battery (open cell, dead cell, the plates inside, etc) is bad. The battery test while the car is running isnt really a battery test, its to test the alternator to make sure the voltage regualator is working properly. Should read around 14, and no higher than 14. If they test low or high than your alternator is bad. And yes an amp can drain down a battery. Your stock system is what the battery is designed to maintain. So adding extra compents to run off the battery will cause it to drain more quickly (resulting in your battery life being not as long). Also you have had the battery for a year, it could of been sitting on a shelf at a store, etc for a year or so. So you could have a battery that is 2 years old or more. Check your ground wire on your car and make sure its connected tight. But I really think you need a new battery. Bad batteries tend to act up when its cold out because it takes more cranking amps to start the car. Like I said charge the battery and test the battery without being connected to the car, and see what it reads.

Battery is fully charged, and has been fully charged. It reads around 12.x when fully charged. The alternator tests around 14 OUT out of the car. Nothing is draining my battery, I'm wondering why the alternator ISNT charging the battery. If I missed a connection, if there are extra ground wires I may have missed...something like that.

The car cranks, the engine starts. The battery does NOT charge, but it MAINTAINS a charge.

I hope that makes more sense.

 

[UW95GST]

Problem solved.

Seems we blew a 100amp fuse some how