HI,

Took my car (2002 XKR 100 convertible) off the road for the winter and forgot (didn't really think about it) to unplug the battery, now the car will not turn over eventhough the lights etc come on when I try to jump start it.

That is the short version. Any help greatly appreciated.

Longer version....

After I found the battery (trunk, who knew?) - I realized my jumper cables were not long enough to reach the trunk where the car is currently parked. I attempted to put the car in nuetral but was unable to get the car out of park. This was attempted while the battery was dead. Gave up.

Second attempt.

Got longer cables, accessed battery, connected. lights come on, etc but the car will not turn over. Did get a few strange messages on the dash - restricted performance, TCS not available, maybe something else, and the battery light was on if I recall correctly. No sound form the engine at all when you turn the key.

It seems like there is enough juice, with the jumper cables attached to my Saab, to turn the car over (although I could be mistaken here). Is there something else the matter?

I have never had the battery die on me so I don't know if there is some problem caused by this.

Thanks very much for your help.

Kip

 

Let the other car charge your battery through the jumper cables for 30 minutes to an hour.

If this does not work, you need a new battery. Car batteries are not designed to withstand total discharge very well.

 

buy a car charger and throw it on there for awhile. Next winter you can put that charger on the batt (or drive it a couple times a month, these car HATE TO SIT) every once in awhile to keep it up.

 

Charge the battery any way you wish. After a full charge take it to AutoZone, PepBoys, Sears or the like and have the battery tested properly. They will tell you if your battery needs changing. Running a battery until dead is not good and I have no idea how old it is so my best advice is to get it tested.

 

Kip,

If you've got a digital voltmeter, it's possible to get a pretty good measure of the battery's charge ... about as good as what used to be possible by dipping a hydrometer in the electrolyte (not so easy with a sealed battery ).

There's a paper on it at www.scorekeeper.com/jaguar/jaguar02.htm

Good luck.

 

You all may remember I had trouble with a dead battery after setting awhile. Just as a side bar. The Aston Martin forum says do not park their car for more than three weeks without a battery minder. Pretty much the same as Jag.

 

Pretty much with any car actually ^

Every few weeks, its nice to do a nice warm-up for the car. Does anyone here know, if your XK8 is completely dead does it forget its window and convertible top programming? I made the mistake for living the xk8 alone for a month, and it forgot the window programming, i had to reprogram it manually.

 

Thanks for the information.

Is there a SOC below which the starter will not operate?.

My questions stems from the fact that all the ancillary things in the car - windshield wipers, heater, etc etc - all seem to work with the jumper cables attached but the car won't turn over. So is the fact that the car won't turn over indicative of a dead battery or some other issue, since the rest of the electronics work with just the jumper cables attached...

I have seen it noted on the site that the car may not think it is in park and thus won't turn over as a result, even though the car actually is in park. Could this be a problem since I did try to move the shifter to neutral? How would I eliminate this as a possibility?

Thanks,

Kip

 

It may be the battery and it could be the “P” “N” switch on the shifter to the trans. Try putting the shifter in the “N” position and see what takes place.

 

A starter puts a very large load on the jumper cables. When the battery is very discharged, it additionally puts another very large load on the jumper cables as it 'sucks' in many amps of current to begin to recharge.

Many inexpensive jumper cables use undersized wire and have poor connections and clamps. This double large load causes excessive voltage drop across the poorly designed cables...meaning your car will not start even when jumped even though your accessories may work. If you do not have a charger, the remedy is to let the other car charge your battery for a while before attempting to start. Assuming your battery is still serviceable, and that you do not have some other issue (such as the transmission lockout problem mentioned above), you should then be able to start your car.

If this works, the prudent advice, also as mentioned above is to get the battery checked. If it is bad replace it, otherwise then have it fully charged or take a long (1 hour plus) expressway drive to make sure the car charges it fully again.

 

Please forgive my ignorance here but does simply attaching jumper cables from my saab to the jag, charge the jag battery? Should the jag be on or off?

I don't seem to be able to get the car into nuetral, the shifter will not move out of park and I don't want ot force it. Is there a trick to it?

Thanks,

Kip

 

Yes, it is that simple. The ignition on the Jag should be off. The engine on the Saab should be running. Let it charge for 30 minutes to an hour. That should be enough to get you to start if your battery has any life left. Try to start it after the charging with the Saab still connected and running for extra boost.

If it does start you will still need to charge it more or take a long drive, or you are liable to continue to have problems due to low charge. Having the battery tested would also be advisable.

Most likely you just have a dead battery, not a tranmission interlock issue from your described scenario.

 

Kip,

I agree with what's been said; it's probably just a dead/weak battery. You can test the battery yourself using a digital voltmeter and the procedures in that paper I pointed out earlier in the thread.

No simple answer to your SOC question. Depends on temperature mostly. Long story short, If the state-of-charge is low the battery may start the engine under "easy" conditions (mild air temperature, engine already warm) but fail when more battery power is needed (air and engine cold).

Good luck.