I've just had my MY17 F-Type S die in a sudden electrical way. Original battery which I was going to replace in a couple of months anyway, but dealer says the sudden death (as opposed to a slow decline) was due to a catastrophic drain through a faulty alternator. Presumably this means that the rectifier and its diodes are at fault. Although this sounds plausible, is it a feeling that this is a likely or common event? I thought diodes were pretty resilient and reliable beasts. I will go and see them tomorrow and I want to be walked through the issue before I get the wallet out.

 

Never heard of this before on an F-Type or for that matter any modern Jag so obviously not a likely or common event.
Before spending big bickies I would get a second opinion preferably from an auto electrician.

 

Back in the day, I've had batteries just seem to collapse in a final gasp without any prior indication.
If you think the battery was likely dying before the event, why would blame fall first on the alternator?
I would get a new battery, make sure it is fully charged and run the car.
Test the battery voltage while the engine is running. You can use a regular voltage meter or
you can buy a plug-in voltage indicator for the cig. lighter position for just a few bucks.
See what happens when you run it. Leave the AC off. Does voltage show charging? Does battery drain again?
My plug in indicator shows voltage between 12.5 and 13.4 when the engine is running.
Then proceed accordingly. What's the risk? You needed a new battery anyway.

 

Has anyone plugged anything into the OBD port recently? Just to eliminate a simple option.

 

SCM had a good question about the OBD and like CJSJAG suggested, I would try the battery replacement first also; but be prepared for the worst. I had started seeing messages of a low battery last fall (2019 V-6 R-Dynamic) which always stopped after putting some miles on it. I attributed that to not driving it enough so I wasn't immediately concerned........I should have been. My car died at the beginning of a short trip with a catastrophic failure of the Alternator and was replaced under warranty. Oddly enough the factory battery survived it all even though being drained to the max trying to get home. Hang on to your ***.

 

Paul: Are you saying that the battery failed and that subsequently caused the alternator to fail?
Did it require a whole new alternator or just a rectifier or other component?

 

Sounds more like a plate in the battery collapsed...

 

And for the record, sudden battery failure is not by any means rare. If you were planning on replacing the battery it must have been because of its age or condition, no? The likelihood of alternator failure here is below the possibility of battery failure through age or defect on the list of possibilities. If you install a new battery (recommended) make sure the new battery is fully charged before installation.

 

AS previous, I would replace battery and check before looking into the alternator.
One thing you might check is to try charging the battery to see if it will hold a charge then how quickly it dissipates with just headlights on.
That will bypass the alternator question and at least give you an indication of the battery state.

 

I had the same issue. The battery was only 1 year old, but my alternator went bad. I first got a battery charging issue. I tried to make it home, but then all hell broke loose with many errors flashing in about 20 miles. I did pull off the highway just as the car died. I needed a new alternator and battery. The former was covered with my extended warranty and the latter by the battery warranty. No problems since, at least with electrics. .