jwog666

yes when the light is on is when there is a fault, however if you take the alt in and have it tested they will be able to load it and make sure that the alt can put out the amps its supposed to, and that the diodes and regulator are good as well, all a volt test tells you is that its making some output, but you dont know if it enough or if it has AC voltage nois from a bad diode.

oxfordgt

If your only getting 12.5v with the engine off you more than likely have a battery that's dying. Your battery has 6 cells 2.1v per cell = 12.6v

To be sure you need to properly test the battery voltage. Charge the battery with a battery charger at the proper rate. 1% of CCA x reserve capacity or voltage of discharge is the proper battery charging method. So if your battery 600 CCA and a reserve capacity of 200 you want to charge it at 6amps for 3h since your battery is only reading a little low. Once it's charged discharge the surface charge (anything over 12.6v) by turning on the lights for about a min. Then test the battery voltage for the correct reading. When charging never connect the negative cable to the battery negative terminal, always connect negative to chassis or engine block away from the battery. Gassing caused by charging could ignite by sparks

If it test at 12.6v then the battery is good and time to check the alt.

jwog666

check out the chart. basically never mind that 1/10 of a volt discrepancy its not enough to matter, plus you just replaced the battery.

oxfordgt

This is the difference between you and me jwog666. There is the correct way and the ford tech way of doing things. Sweetbeats it's up to you which way you want to do it but if it was my new battery that is reading low already I'd want to know for sure so I can get a refund.

jwog666

there is the correct way and the oxford way = waste time checking things that arent the problem. take the battery in, they will test it and tell you its good, then post back here. but in that time you could fix your car.

oxfordgt

You are a giant jackass that I highly doubt went to any type of automotive school and are just a google mechanic.

From the beginning of this thread I had said the problem is the alt. Battery light only comes on when the alt is not producing the correct power output (14.5v). But if he is getting a low reading from his new battery he could have a broken plate in a cell that will only get worse so he should check it.

jwog666

you can think whatever you want, i need to prove nothing to you, my credentials are what i have stated. his battery is not the issue. go out to any car that has been sitting for an hour or more and check the voltage, you will find that a great deal of them are less than 12.6v, however this is not a sign that they are bad. i test 15-20 batteries a day with a midtronics mdx-p300 and most will have a starting voltage of 12.4-12.5, some 13.0, they all test good as long as their amperage output is within 20% of their rating % of charge is not an indicator of battery health, just % of charge.

oxfordgt

Just checked mine that's been sitting for 2 weeks. 12.6 on the dot. LOL you so called "ford techs" crack me up with your good enough attitude. I guess I'm just used to making sure every single part of a car is working 100% perfect to get the best performance.

Just stick with Jwog666 sweetbeats he's a ford tech and will eventually tell you if the battery light only comes on every once and a while it's good enough.

jwog666

only an idiot would say that, possibly the same idiot who would keep posting about testing a new battery when the alternator is the issue. i bet you are an expert on rectal exams too, seeing as you head is up there most times

Soldier GT

Just had the same issue. Battery light came on, took it to Oriellys, checked it out discovered it was the alternator. Spent a 188 bucks for the alternator as well as the installation. Picked the car up yesterday and bam she runs great..