My car suddenly died on me last night. My local mechanic just called and said that the battery is dead, so he hooked up a new one, and when he put it in, it was over charging, but then it stopped. But he said that would probably happen again and is an alternator issue. Any thoughts? Does that sound right? any idea what thats gonna cost me and if i have to buy Jag parts or will a ford/ lincoln, or generic fit?

 

I always take my alternators in to a place and have them rebuilt, that way I'm guaranteed it will fit back in. Any auto or marine elctronics shop can usually do it. And it's cheaper than getting a new one.

 

Sean, what I would tell you to do is to connect up a multimeter across your battery and then start the car as you watch the multimeter. You should see it rise up to about 14.4 VDC for a minute (or a little less) and then it will settle back to around 13.7 VDC. If the mechanic is not familiar with how Jaguar's manage their electrical systems, he would think that the alternator is overcharging the battery. Now, if the voltage is shooting up to say 15-16 VDC, then yes, the alternator is overcharging and a good look at the electrical system is needed.

Let me know what you find and we'll take it from there.

 

let me start off by saying hes not a Jag mechanic, but hes a good and has done well by me on the MANY issues ive had with my jag. but he might not know that. but yeah, he said when he first put the new battery in it shot up to 15 but settled at 13.5

 

but he said that the old battery was totally shot, and he thought that it had over charged and killed that battery. but i didnt have any signs he said i should have had, like extra bright headlgihts or dash lights

 

Sean, the idea behind the voltage boost right after starting the car is the ECU is trying to replace the energy that was used to engage the starter. Is it truely needed, no. But, if you were to start/stop/start/..... many times back to back (why, don't know), then it would make a difference. Personally I would not worry about looking into the alternator unless your new battery bites it soon.

What you are describing sounds fairly normal for what Jag does with their cars.

 

so does what happened to me sound par for the course of just a battery dieing? it was running fine and i turned it off to pump gas, got back in the car and it was dead.

 

Sean, normally batteries don't die like you said, but then, what you describe is exactly what happened to me when my battery died. Odds are what happened is as you were driving, a plate broke off inside the battery, leading to a bad cell. As long as the engine is running, you wouldn't see a thing. But, once the car shuts off, the electrical system would be junk.

Smile and move on. I was fortunate enough to have this happen as I was pulling into the parking lot of a auto parts place. They actually let me pull a jump starter box out of its packaging to get the car started up. Needless to say, I bought the battery from them once they got on in stock (brought over from another store in 2 hours).