I, along with many others on the XK (2006+) forum, had low battery problems with my XK and my XKR from infrequent or short trip driving. Every time the battery went low there were all kinds electrical gremlins that would appear. The Jaguar service reps would always ask me if I left the fob in the car or even in the garage as they said it would cause a battery drain.

I don't know if it is the same with my F Type R, but to be safe I always double click and take the fob in the house with me. Also, if I only make a couple of 1 mile trips in a week I put it on a Battery Tender Plus overnight every week or two. It's been 10 months and no problems.

 

When I took delivery one of few warnings was to not leave key in car. I assume they had a problem previously. On our Maserati we never leave key in car ,well because it is a Maserati!

 

Very interesting, jleuz1. So there's evidence, albeit anecdotal, on both sides of this FACTUAL dispute: When the fob is left in car, (1) everything shuts down after 10 minutes or so, vs. (2) some systems remain active, or at least one ("body control module," whatever...). The preponderance of evidence seems to favor (2).

Still, I find it exceedingly odd that there's NOTHING in the Jag documentation on this. So we're reduced to "this techie said..., I've found that..., try this and see if..."

Jag, are you there? How about some authoritative pronouncement from on high?

 

For me it doesn't really matter if some systems remain active...even if all systems remained active, the real question is how long can these systems remain active without draining the battery too much?

 

I've left mine unlocked for over a week (key in house though) and it turned over great.. no problem.

Anyway, easy fix.. just take the key out and lock it.

I keep the key in my pocket when I drive it as I'm concerned I may get out and leave the key in the car, lock it and then the key is locked in the car... this can happen if the key fob battery is about to die as attested to by a friend of mine with a different make of car.
Lawrence.

 

The message center will tell you when your key fob battery is low (I've actually made it through 82 pages of a 243 page owner's manual. Like reading Tolstoy)

 

I signed up for TOPIx Jaguar, have another week or two (google TIPIx Jaguar), just spent an hour wading through all the technical documentation. The radio receiver for the keyfob remains active when the cars off, apparently always.
Key topic is "Quiescent discharge" and our cars have a Quiescent Current Control Module (QCCM) that watches the current drain, then talks to the Gateway module and the CAN bus (links to everything). If discharge is sensed, it can turn things off... (yes, it's on itself).
JLR Battery Care recommendation: "Over time when vehicles are left idle in storage yards and showrooms routine battery charging will be required. If batteries are allowed to remain discharged for lengthy period then they cannot be recharged and a replacement battery will need to be fitted. To minimise quiescent discharge the transit fuse should be removed from all vehicles which are to be left in storage for long periods of time. Every battery on a stored vehicle or in your parts storage warehouse must be tested, and where necessary, recharged every 30 days and MUST be recharged every 90 days to maintain optimum battery health."

I can't find anything on leaving the key in the cabin or not! Maybe someone else can find it in the War-and-Peace of the technical documentation

 

There will be no documentation on how quickly the battery discharges with the key left in the vehicle permanently. I believe that is the only question left. The vehicle will discharge more quickly with the key in left in the vehicle, its just a question of how much more quickly and if that will affect anything during the OPs typical usage of the vehicle.

 

I believe, stohlen, that you've summed it up nicely.

 

Maybe that's the "Low Battery" message I was seeing. I thought it was referring to the car battery.

I have two fobs, and I keep them in a drawer and just take one out when I'm ready to drive. I bet one of them has a low battery, and that's what it was warning me about.

 

If so, the message will say "Smart Key Battery Low". https://topix.jaguar.jlrext.com/topi...2728706!!10!20

 

I wonder if they recharge if you put the key manually in? My Audi did, my Merc didn't.

 

No, I think the fob takes replaceable button cells. And the only key is an awkward folding metal one you remove from the fob, in case the fob is completely dead.

 

Put it in where? There's no cradle for the Smart Key. Besides, these button cells will last years before needing replacement. Never needed to replace one in either the 2002 or 2009 MINIs.