Thing is - it's no harder to follow jag advice than to ignore it, and it's safer to follow it. So why not follow it? It's what we over here call a "no-brainer" i.e. you just do it. In case you do engage brain then you still do it.

 

I have been pleasantly surprised to see all the input on the topic of jump starting your car. I am also surprised to see the many that are basically say it is not a problem when in fact it is. On this forum alone we have had many who suffered much damage because they did not take the precautions necessary to prevent the damage they experienced. Please remember this is in fact a healthy discussion that should not be taken lightly this is a real problem.

 

Sorry Gus, I must totally disagree. From my personal experience with two XJ's and an XK there is no need to follow any 'procedure' when jumpstarting because. out of ignorance of there being a 'procedure', I have done it *****-nilly. However, care must be taken to ensure that the battery area has been ventilated for a few seconds.

However, forget about procedures for a moment and think more deeply about what is being said. When a car is jumpstarted it already has a battery in it (although it may be flat). That battery acts as a 'damper' when the second one is connected in parallel. Disconnecting the second battery is no different to switching off a high load accessory, such as the screen heaters. It's also worth remembering that not many IC circuits are run at 12V, most being in the order of 3.5V to keep heat generation down so they have power reduction circuits built in.

If you want a 'precarious' situation, that will be a hard reset with the biggest spike possible - 0V to max battery voltage instantaneously. I have also done that - and it still didn't blow my car up!

By all means advocate, and follow, a jumpstarting procedure, but the statement that it will blow your electronics just isn't correct. (Incidentally - there is a condition worse than a hard reset even - a Booster Set connected via the cigar lighter).

 

A Booster Set connected via the cigar lighter - It's a tool of the devil.

 

I believe the lighter socket is protected by a low amperage fuse (5 amp?) so pretty difficult to boost a car with that type of current.

 

I don't expect you could do any damage anyway.

 

(Except to the fuse and perhaps your temper when you realise weeks or months later that you blew it and how.)

The problem isn't with connecting a second battery - it's connecting a running alternator! And then the 2 alternators fighting each other, followed by disconnecting the pair of them. That's what jag are wanting to avoid, as well as recommending an earth point away from the battery negative, again for reasons I think have been stated. But hey it's the owner's car and if they like taking risks let 'em carry on. Not me.

 

Fair enough guys, but Jaguar themselves, in my handbook have given instructions on how to jump start, with images, why would they do this if they didn't want people to do it?

 

Ok - ok I admit it ....... I have a 'thing' about procedures! (Out of interest does anyone have a BMW or Merc - and do they publish a similar procedure?)

We Brits seem to be becoming obsessed by procedures and they are worded in a way that suggests that if you don't follow them some catastrophe or other will occur. Most of us are intelligent enough to realise when a set procedure is necessary - such as - place firework, light touchpaper, RUN!

The latest one I have come across appeared in the washrooms of the plush office I worked in as an engineer for a large Utility company. It was a little sticker above the handbasins and gave a procedure for washing your hands! (Most of the people in the offices either have Doctorates or Phd's and so we knew how to wash our hands!) After that we all kept a close watch on the inside of the cubicle doors for another procedure - How to wipe your ar.. !!

 

Maybe they were REALLY hoping people actually would wash their hands - apparently a lot of men and fewer but still a lot of women simply don't

 

2000 SType Alternator Failure! Well I drove to OC Md. for a short vacation and after the fourth day we took a trip to the store when the battery light lit up and we made it to the condo. The next day I went out to see if it was the battery or the alternator and the battery was down to 8volts and was not enough to start( turn the engine over). With no battery charger I used the “Pilot InstaBoost 400-amp” that was in the car (glad I had it) and it started the car 2 times without any trouble. Replaced the alternator and used the Pilot again to start the car and it did all 3 times without recharging the booster.

Changing the starter was not as bad as I thought, removed the splash guard (two screws), removed the battery terminals from the battery, removed the power leads and three bolts from the alternator and it was out from the bottom and this was done in the parking lot of the condo.

The only thing I could add is for you to have ALL your tools! I managed to only have my sockets. What was I thinking!

I am not selling the product just wanted you to know it works!

 

Uncle...... UNCLE!

Gus, old buddy, you win. I'm a convert.
I guess I'll add one of those to my arsenal. I've seen those used a few times with disappointing results. I will have to assume there must have been some operator error of some sort, or poor maintenance involved. If it got you out of such a jam, the merit is there.

Thanks, Bub!

 

I did a bit of googling and generally found mostly positive reviews of the one at Costco. There was even a YouTube video that showed it in action.

Way in the past I recall oftentimes jumpstarting my older vehicles off of other vehicles but the practice was always to have the other vehicle running so as not to sap their battery. It looks like the Jaguar procedure is to NOT have the other vehicle running. I wonder if this just a very conservative recommendation (like unhooking the battery whenever you do anything on the car) or if there is really any actual risk to the electrical system under some (rare and unusual?) circumstances.

Doug

 

Some members have been converted to following the Jaguar recommended jump start procedure only after becoming surprised owners of fried modules.

Graham

 

My mother has been jump starting vehicles successfully and without
mishap for 50 years.

Some people overthink things or are incompetent.

That does not mean jump starting a vehicle is inherently
risky.

 

I replaced the original battery with a new Jag OEM battery in July 2016. Sorry for the wordy details, but this info may be helpful to resolve this problem.

Today was the first time my XKR would not start. I last used the car 10 days ago. I use a CTEK battery tender only full time during November to April when in winter storage. I have not used the CTEK during the spring or summer. I have only put on about 1200 miles intermittently since mid April and not much long distance driving.

When I went to start the car today the Smart Key was non responsive. Engine would not start. No instruments lit up. Power trunk release would not work. Door locks would not work. I opened the trunk with the manual valet key to access the battery. The dealer has told me to always lock the car when not in use, this is helps reduce the amount of grey power used by the on board computer systems that can drain the battery?

After accessing the battery, I plugged in my CTEK, instantly the front and rear lights started flashing with very little illumination and the security horn was beeping very faintly. I then uplugged the CTEK after 5 minutes, waited 10 minutes and plugged in again with the same light and horn problems.

I called my Jag dealer and explained the problem to them. They recommended to disconnect both battery terminals and wait for 30 minutes before reconnecting them. This would reset the battery and the alarm. As soon as I plugged the CTEK back in the same thing repeated itself with the lights flashing and the horn beeping very faintly.

I then read the manual and followed very carefully the instructions to jump start the battery from my other car. As soon as the battery was connected the lights starting flashing with full intensity and the alarm horn was beeping very loudly. I pushed the smart key to disable the alarm. The horn stopped beeping. I waited a few seconds to start the car, a lot of dash lights on, the CD changer was making a noise too. After a few tries the battery did not draw enough from the other car battery. I think the jumper cables I borrowed from my neighbour were only 8 or 10 gauge and not enough draw to jump the dead battery. Perhaps I should have let the live battery from my other car charge for several minutes before attempting to start the Jag. Maybe leaving it longer would have also corrected the on board computer resets?

I was thinking of buying a 4 or 6 gauge set of jumper cables in the morning and trying the procedure again. Or alternatively disconnecting the battery terminals and putting on a 12V trickle charger for a few hours to charge the battery and then to attach the battery terminals once completed. If I use the trickle charger should I consider removing the battery from the car first or leave it in?

Any advise and experience to help remedy this frustrating situation would certainly be most appreciated. It is supposed to be a fantastic day here tomorrow and I would really, really like to take it for a nice long drive!!!

Many thanks
Cat2

 

regardless of the age of your battery, it's dead. Pull it and return it for a replacement.

XK's will drain the battery. the battery maintainer is a must have at all times when driven infrequently. Yes locking the vehicle does hasten the shutdown of various systems but there's always a drain.

The x150 forum is full of these threads.

Regardless of the manual, avoid jump starting from another car. Heed the warnings in this thread for future reference. The computers from both cars, and there are several, do not play well with each other and you can fry your electrical systems. Last resort only.

 

Sean W, thanks I am having difficulty posting a new thread for some reason. The post a new thread link isn't showing up on my homepage?? Can you help. I am a member and haven't used the forum for a number of months do I need to re register?

 

NO - you do not need to re-register.

If your account had become inactive, you wouldn't have been able to login or make posts #76 and #78.

Graham

 

It will take from now till doomsday to charge a battery with either a trickle charger or a battery tender. They're not built for such a duty as their output is only 1 or 2 amps, max..

Get a real charger of at least 10 or 20 amps and let the battery charge for a few hours before trying to start the car.