Well the good news is that my car is now about 5kg lighter, after I pulled about 480 Bunnings receipts out of the back and spare wheel well . The not so good is that I cant see any way to get under the carpet on the other side, I also couldnt see any cables. Having pulled out the centre section of carpet, mine looked like the one on post #2 here https://www.jaguarforums.com/forum/f...attery-145869/, and my reading is that if you can see the silver bit it doesnt have the second battery.

Build date on mine is September 2015.

 

Yep, that proves you don't have a second battery and that your "performance guys" have no clues.
To get your AC working again you need to fully charge your existing battery or if that doesn't work the battery is kaput and you need a new one.

 

Thanks a heap for your help on this, just to conclude here is a pic aiming back toward the rear of the car, I have no idea what the black thing is.

The mechanics reckon they checked the VIN with Jag which is where they got the second battery thing from, my interest is in not wasting hours taking the car back and forth to get this sorted especially with the a/c on the fritz, I'll have the charger in a day or so anyway. Anyway I'll let you know what the upshot is when it is sorted. The car is sounding fantastic with the CAI (Mina lower section), also the muffled noise issue corrected by itself a few weeks ago (wtf?) and I am thinking it has more beans since the CAI went in, it isnt just that I am driving it harder to get the sound, so you've given me a few good tips lately, I would like to repay the favour but unless we are talking about Japan travel, parrots, or law, I'm pretty useless...


Edit - googled the part number, it is a control unit

 

When my 2nd battery died (years ago), there were no consequences other than start/stop stopped working. Like many others, I eventually removed the battery.

 

Yep, that's the spot where the secondary battery would be if your car came with one.
(replying to BruceTheQuail)

 

Your car does not have a second battery. Only the first two model years did, and that only controlled the eco stop/start. That was ditched by the 2016 model year everywhere (sooner is some markets).

 

I'm so happy you mentioned this. I was just researching why my windows won't go up automatically and was going to read my manual and this forum. I knew it had to do with my recent battery replacement.

So to support your suggestion, yes you do need to reset it after the battery is replaced.

 

Really? That's interesting. I guess time will tell for me since I just installed my battery 4 days ago.

 

...and so it continues, I thought to check with Jag direct and they are saying I have the second battery, no wonder the mechanics have been led astray. So I have asked Jag to tell me where this mysterious second battery might reside...

 

Probably under that spare tire and the dead body...

 

well to be fair, there was about 14kg of hardware receipts back there which have accumulated over the past 8 years

 

To the OP. If your battery was draining even with the ctek connected you almost certainly have the module battery drain issue. I discovered that just after I bought my car. Triggered by an OBD session that didn't shut down correctly. In my case it's the annual state inspection. Simple fix - disconnect one battery terminal, count to 30 and reconnect
If you don't do this, one of the modules doesn't shut down properly and drains the battery within 1-2 days

Your battery may have been bad too. But - I'd put money on this being the problem. Common in 2016 and 2017 cars. (Maybe on others too). Jag aware but no fix..

 

Replaced the CTEK all is fine now..thankfully

 

sigh, my trials are continuing. Car back at the mechanics, they reckon there is a problem of some description and it want a battery issue but the battery wont charge when it is in the car but would when it isnt (dont understand that given that the charger essentially just works from the + terminal and the earth bolt on the (-), anyway watch this space...

 

If it won't charge in the car it suggests there's an electrical drain that's consuming more power than the charger is supplying.

 

sorry, it wouldnt even get into charge mode on the CTEK charger, it failed at the second level

 

My handbook says that means the battery won't accept a charge so is defective. But it charges when out of the car's circuitry? Maybe the BMS is faulty? If you try charging straight on the battery terminals you can maybe eliminate that as a possibility.

 

Another update, it has actually got a bit funny. So the saga goes like this (approx dates):
Day 1 - car in for service, new battery installed;
Days 2 - 5 - car running fine but low battery warning coming up at first start of day;
Day 6 - air conditioner stops;
Day 8 try charging battery, fails at second stage;
Day 10 - car goes back, battery fine but a/c compressor fried, battery ok but circuit needed fixing.

So now I'm waiting on the compressor and should have the car back early next week, the cost is pretty reasonable so I'm not worried about that (I am happy to spend $5K a year keeping the car on the road, a lot better than torching $30K a year on depreciation for a new one which is almost identical). i also am not interested in blame attribution for how we got to where I am, but I am genuinely interested in thoughts about the failure of the compressor, looking online it doesnt seem to be a common issue at all, the mechanics dont think it is related to the battery issues. It's a bit like when someone goes in for minor brain surgery and they have a stroke on the table and you think "hmmmm, what went wrong?" but then the surgeons say "Jeez you are lucky you were in hospital for that completely unrelated thing, as the stroke that you got when you were having surgery (which had nothing to do with the surgery by the way) would have killed you otherwise" and you think "that is a mighty coincidence, one might think a very unlikely one" but then you cant be bothered getting invested in the argument because these things happen.

But out of curiosity, any thoughts about the likelyhood of these two events happening spontaneously and independently?

 

Maybe the electric clutch on the A/C compressor failed due to low voltage?

 

If the alternator has failed/is failing and it's putting out incorrect (low) or spike voltage it's possible that other components with electrical connections could be affected. You can probably prove correlation but you'll never be able to prove causation.