My car (jag xk 2006) went dead when I left it parked for 3 weeks. Understandable. I charged it and all ok. I made the same mistake a couple more times. Then one day when I was pumping up the tires at the garage it went totally dead. No lights. No dashboard. Nothing. I got it jump started and at home I charged it again. I then spent £200 for an auto electrical place to check it for 4 days, telling me that the car had no parasitic drain and the alternator is fine, and the battery is good.So, all good, £200 please. Then it happened again whilst filling with petrol at the service station. I've put a CTEK gadget on it and it charges up perfectly, but I know its going to happen again. What to do? Could the battery actually be clapped out and not hold a charge despite them testing it and claiming its good? I don't drive very much, and mostly short journeys, but it never used to happen. Anybody intelligent out there with any ideas?

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    You don't suddenly go from "running OK" to "not even dashboard lights" because the battery isn't charged. If the battery runs completely flat while driving, usually the engine stalls when the RPM drops to idling. You must have an intermittent bad connection somewhere. Likely candidates are the battery terminal connectors, and the earth strap to the car body where the body end can get corroded. An intermittently faulty ignition switch or relay might be another cause. BTW "3 weeks parked to flatten the battery" is a bit short - 3 months might be long enough for it to go flat but not 3 weeks IMO.
    – alephzero
    Jan 17, 2019 at 12:13
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    Given your story, I would suspect a broken internal link in the battery as another possibility - had this happen to me, an absolute so and so to find... as intermittent problems are so difficult to isolate...
    – Solar Mike
    Jan 17, 2019 at 12:26
  • Concur with @SolarMike here ... I'd suspect the battery is the root cause of your issue as well. With the right tools, a parasitic drain and/or bad alternator would be easy to spot. The battery is really the weak point in the chain. Also, if the battery is anywhere close to or older than five years, it's time for replacement anyway, so changing it wouldn't be a bad idea. Jan 17, 2019 at 13:48
  • I have a jag (x-type) and if I am going on holiday for 3 weeks and the car won't be used I connect a battery monitor / charger to it to keep the battery topped up. The reason is that the jags do like a properly charged battery otherwise many spurious faults start to appear... This has been noted by many owners and even the best jag techs say the same : keep the battery topped up...
    – Solar Mike
    Jan 17, 2019 at 17:38

1 Answer 1


Sounds like your Battery was already old, not sustaining charge over 3 weeks. On top of that, when you completely drain you battery it can get damaged further. What you describe sounds like that.

I had the same behavior with my Toyota Aygo a while ago. The battery could not stand the load of the starter motor any more. Changed the battery and all is fine now.

(My Mechanic called it an "internal shortage", read about it here)

I suggest you replace the battery, should be a lot cheaper then spending £200 on finding nothing and actually solve your problem.

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