Here's hoping it's just a dead battery that won't hold a charge.

 

The strange thing is that it seems to be very random which car that is affected.

Mine is in winter storage now (in a not heated garage, and temperature had varied between - 8 to + 6 celsius), and I plugged it to a Ctek charger after 3 weeks. It took only 5 hours till it was fully charged, so no problem at all here.

 

This issue is a sudden failure. My car has previously sat for almost 2 weeks with no tender and didn't show a low battery warning on restart. A few days before this last trip it began showing a low battery warning every morning. Temps have been fairly warm here, so not temp related.

 

Interesting - thanks. Please keep us updated of what is being done and how it is fixed.

 

Good luck my friend! While I drove my 2015 V6S throughout all of last winter, there were periods of time, 2-3 weeks at a clip when I was on holiday and without any battery tender (even though I did buy one) the car started up without any [battery or otherwise] issues at all. And it was colder than a witches you-know-what throughout. I'm sure by May you'll have it sorted out .

OK, well before.

Best regards,
Jay

 

........how often this question comes up. Is it a bad battery? They often test OK, so the culprit is assumed to be an unexpected parasitic load with ignition off - what didn't switch off that should have? Why don't the mechanics check out the parasitic load with the ignition off? With a proper Amprobe or similar, it's a simple matter of clamping the jaws around the main battery cable....no need to disconnect the battery and put a high current meter in series. {Note, most Amprobes do NOT read DC current using the jaws; the jaws only read AC current. However, select higher end Amprobes do have technology to read DC current read using the jaws.} What am I missing here?

Desert Hiker

 

+1. You are dead on. I'd check this thing out myself if I had a DC Amprobe. I suspect the dealer may not have the right equipment either.

 

Not to worry. I have jumper cables. (and I know how to use them properly)

 

I'm sure you do - as do I - but do you know how to eat (nay, dissect) a lobster? That's to be seen.

 

I will defer to your knowledge on that matter and look forward to your expert tutelage.

And yes, if it's edible, I'll eat it (live monkey brains excluded).

 

See post #59 in this thread:

https://www.jaguarforums.com/forum/f...-147405/page3/

In addition to TXJag's "paint causing bad ground" diagnosis, the above post discusses reflashing of the "gateway control module," which another dealer claimed JLR had issued guidance on. Those are the two things I'd look at first.

Mine continues to be fine, and I don't keep it on the BT nearly as much as I used to. This is another one of those vexing issues where most cars are fine, but too many are having these kinds of issues.

 

Just read through this battery thread, late as I am. Learned a few things, like a lower charging rate for the Jag, possible AGM susceptibility, module issues, some AC-DC stuff, etc. Much appreciated, y'all.

A number of you questioned the battery itself. I've personally found the battery (several were AGM's) defective (on non-Jag cars) more times than I would have ever thought, however new the batteries may have been, and however the batteries may have performed in bench-testing and actual driving. I've had starting issues and driving issues, including a frustrating array of display pop-up's and codes thrown (sometimes once only) that just couldn't be traced to a defective module, BUS issue, or other electrical gremlin, even after all the dealer tech diagnosis and time invested by all concerned. A new battery did wonders. Not saying the battery is always the culprit--just don't assume it isn't.

Also, TXJagR's posts about paint on a grounding strap was a good reminder. I used to watch my older son and his friends race tricked-out imports and participate in local car audio competitions. They attached additional ground straps all around the motor and frame. I don't go that far; but, I do try to closely insure all existing grounds are "clean," whether in a new or older vehicle. The little things, huh.

 

Hmm... Mine now insists that I start it immediately on entry due to low battery voltage if I leave it for more than 4 days. Starts perfectly though.

 

Already sanded down the paint around the ground cable connection to the frame. I'll see how that affects things tomorrow morning. If same problem, I'll insist on a reflash and have them hold the car overnight to confirm all is well. Thanks for the reminder on the reflash.

 

The car is back in the shop. All reflashes including the battery module reflash had already been done except for the O2 sensor reflash, so that is now done. They could not get the low battery warning to recur, so they will start the car a number of times and hold it overnight for a couple of days to see if they can induce the warning.

 

Of course, the dealer found absolutely nothing wrong with any part of the charging system. Told me to take pictures of the low battery warning when it next occurs.

 

I made the mistake of plugging my cig plug voltmeter into the power outlet because this is the first car I have had without a voltmeter in a long time. The results were perplexing and I found this thread with a search.
The remaining puzzle to me is what the Jaguar "engineers" had in mind for battery charging with the alternator. With the way the voltage behaves it just does not seem that the battery would ever be fully charged since the voltage is almost never in the range of 13 or more in daily driving. Maybe on longer trips but I have not tried that yet.
Lead chemistry batteries like to be fully charged for maximum life and capacity. I do not drive my car every day and I do not take long trips very often. Consequently, I have concluded that the smart move, for me, is to leave my car on my battery maintainer most of the time. We had a bad experience with my wife's Mercedes a few years ago where her short distance driving never fully charged the battery and it ended up dead in the garage overnight. I do not want the same experience with my F-Type.
Larry

 

Yours is behaving like all others (normally), and only occasionally do I ever see a very short spike above 14v. I have a maintainer hardwired into the battery bus in the trunk, but I only hook it up if my car has is idle for more than 2 weeks. I've not had a problem in 2 years.

 

I also have a battery tender 3A hard wired to the bus. After driving many short trips for a week, it took more than eight hours to fully charge. The instruction book said that the car's charging system will never fully charge the battery. Only the tender will. I now just leave it plugged in when not using it because it is so easy in the garage.

 

Thanks, I also have my connector hardwired in the trunk and my maintainer is now mounted on the garage wall at the rear of the car with a switch to turn it on. It is only the effort of opening the trunk and closing to connect mine so I will continue to keep the battery fully charged. Just the OC in me.
Larry