Good morning
This is a question on battery failure modes.
On Monday, I go to take a drive in the 2008 XKR. Wouldn’t unlock. Swapped key fobs and still nada. Unlocked with the emergency key and no interior lights came on. It’s the battery!

I had driven the car the previous Thursday with no problems. The car had started right up as usual. Battery voltage on my radar detector ( not a volt meter but a good indication of relative battery status) looked good and showed about 14.2 volts drifting down to 13.8 volts as the alternator charges the battery recovery from start up draw down. I routinely connect the maintainer once a week to keep the battery topped up. Weather is warm but not particularly hot.

Checked the existing battery voltage with a meter. Like 4.5 volts!! Figured a light had been left on so put my maintainer on the battery overnight and voltage only came up to 5 volts. Battery connections were clean and snug. Time for a new battery.
Battery was an Interstate MT93/T8 800 CCA with a Feb 2019 sticker on it (outside the 24 month warranty now of course). Replaced with an FPV platinum group 49 830 CCA which my local, trusted import parts guy says is an excellent battery with a 30 month replacement warranty. He sells a lot of these and says he has only had 2 replacements under warranty. We’ll see but at $115 I figured it is a good deal.
Replacement battery showed 12.3 volts as received so charged it overnight to 13.1 volts. Car works well now.

My experience with failing batteries is they fail gradually. Cars become slow to turn over especially in cold weather or lights are dim. From this forum, maybe people experience dash messages or entertainment/nav screen errors as the battery voltage drops. Never had such an abrupt battery failure before with no warning.

Have any of you forum members experienced abrupt failures like this? What would cause this? A mechanical fault in the battery internals?

 

That's how all of the last several battery failures have occurred for me. They're great one day and totally gone the next. I've been fortunate that all have failed while at the house and not out someplace.

 

I have had an issue where I'll walk out key in hand and open the door but there is no power, key fob has no effect, so I'll use the emergency key to open the trunk, I check the voltage at the jump start post and I have 12.9v. so it looks like a relay or something that is not working. I found that if I short the connection for my ctek it will then pass the power on, usually activating the alarm. real confusing since the only thing I see is the over voltage protection module in line.
Any Ideas?

 

I've never had any battery fail so abruptly in almost 40yrs of driving. I also invest a little more in a Bosch battery with a 5yr warranty and the largest size that'll fit my car, here in the UK it's a type 019, stock is a type 017 (but stateside you'll have different references)


Have had to replace 3 within warranty period which I think means my philosophy has paid off

Also remember that the battery supplied with the car is supposed to drive the items the car has fitted from factory, so when you start adding radar detectors, trackers and dashcams (I have all three) it'll draw more.

BoL

 

Every failed battery I've had, happened without warning.

 

I've had sudden & gradual failures. (I guess it depends on what failed.)

 

The typical failure mode of modern batteries is not displayed as gradual degradation. It is abrupt, complete failure. Fine one day, not enough voltage to start the engine the next day. Some owners ignore the very earliest signs of a failing battery in modern cars: random warning lights, windows, door locks, top latching not working as they should, the touch screen freezing or delayed in opening...
The use (highly recommended) of a good battery maintainer such as the CTEK in fact masks the symptoms of a failing battery for some time. But eventually the "no start" scenario happens.

 

My first sudden failure experience. Fortunately, the car was home in the garage.
I do have jumper cables in the car as well as AAA premium membership. I’ll look into a jumper battery pack as well. AAA can be a long wait. Fingers crossed I don’t have another battery problem any time soon.

 

I've had warnings. When my battery is not totally fine, I can get no nav and no ACC working. I drive a trip, stop start, all is fine. Now when this happens after months of not driving, I consider that normal (for a Jag ;-)). But if it behaves like that after only been standing still a few days, it's time for new battery IMO.

You may get other warnings. Ignore at your own peril...

 

Do you not use a battery minder such as the CTEK unit? it will keep your battery charged all the time that the car not in use - and will eliminate the symptoms you have experiences - as well as making the battery last much longer.

 

Thanks, and yes. But I have 9 cars and I've been to cheap to buy 9 CTEKs (lamest excuse ever??). I have just upgraded from 1 CTEK to 2, so this winter, yes the XKR will on the charge.

 

ANY battery should be exchanged at 6 years. If you want to be on the safe side, make that 5 years.

Cheap insurance.

CTEK or not depends on frequence of usage.

Just my 2 cts, Hermann

 

I wish my battery had made it to 5 years. Despite my best effort to keep it charged, only got 2 1/2 years. Hoping for better life span with the new one.

 

Yep, those ChemE guys know what they are doing.

These days when they say three year warranty they design it for that and not more.

 

Yup have had it a couple of times , come out after a couple days and completely dead, no apparent reason. Hasn't happened for awhile now, same battery.

 

Jaguar batteries should have 9 lives.