Charging System Problems

[kronik 10+ year member]

Alrighty..

So since I've had my alternator switched out, my battery light has been on. I'm thinking hm, perhaps either the battery was going dead or as someone suggested, the computer might look at it as an over-volt problem. Fine by me.

So, I went out and bought a new yellow-top Optima from Auto Zone.. had to jiggy-rig to get it in there (does anyone know of a place to buy a slightly shorter tensioning brace thing, the thing that goes into the brace that holds the battery down, that hooks into a hole and you tight the hex nut at the top to make the fit snug)?

Anyways.. so I check the DC voltage using a multimeter from Radio Shack. At the battery it's reading 12.08 when I check use the positive probe on the + terminal on the battery and the negative on the - terminal on the battery. Hm. So then I try alternator lead to ground, also reporting a 12.08. What the hell is going on?

I'm about to call an alternator place and see if they can test it.

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[jacko 10+ year member]

Don't electrocute yourself but try it when the car is on. If you did this, some alternators don't turn on until about 800-1000rpms, so you'd still be running off your batttery which would explain the voltage being same as the battery, and not the 13.8-14+ that most alts put out. Idk just a thought i have no clue if i'm right.

 

[johnecon2001 5,000+ posts]

not correct. The alt should be putting that (13.8-14.4) volage out all the time. The amps that it puts out at different RPM's increase or decrease.

 

[kronik 10+ year member]

not correct. The alt should be putting that (13.8-14.4) volage out all the time. The amps that it puts out at different RPM's increase or decrease.

That's what I was thinking, not to mention, supposedly the battery should be putting out around 12.8V.