www.jec.org.uk

Afternoon all. I've an X358 which fits into the garage ( just ) so putting it on a trickle charge can be done, although its a bit of a faff. Clearly if I know I'm not going to use it for a while, that's what I do.

However, what I'd like to know with out experimenting is how long could I reasonably expect it to sit without a trickle charge, assuming it's well charged ( it's on a newish battery ) at the time.

Anyone got any thoughts or experience ?

Double locking puts the car into the lowest possible current draw state.

The answer to the question is a bit like the length of a piece of string.....only by watching a volt meter will you ever be able to see to what level battery voltage has decayed. Re-charge is required if the battery drops to below 12.8v.

Mike K

many thanks

kr

We went on a cruise, leaving the car in the drive with an almost new decent battery; when we returned, about 3 weeks later, it wouldn't start. I don't get problems leaving it for a week.

I'd leave an X350 at most a fortnight without a charge - I've bought ( but still not fitted) a solar cell to trickle charge if it's not within reach of a power point for more than a week.

Interesting point re solar cell; where & how would you fit it ?

sorry silly question really, I've just looked them up and it's all self evident !

My car is 2003 4.2 XJR.

I see there are lots of posts on here regarding dead batteries, power drain etc.
Mine tends to last about a week, before there’s not enough power to start the car.
Mine was previously in the garage on a trickle charger, so it hasn’t been a problem in previous years. but another car has bumped it out now onto the driveway.
I have a good 100Ah Yuasa battery fitted. I did try two other batteries too, from other cars to double check.

I have done a parasitic drain test with a multimeter across the negative terminal. With the boot interior lights removed, all interior lights off, glovebox interior light checked and it does extinguish.
Boot lights do extinguish too when it’s closed (yes I did get on and close the lid on myself to be sure!)

After the car settles the lowest the drain drops to is 0.75A. Which I would think is still too way high?
I have read elsewhere it should be 30Ma? Is that correct?
I have pulled every fuse on the car, across the three Fuseboxes. The only time it dropped to 0.66A, was with fuse 28 in the cabin fusebox (climate control modules).
I was expecting to find something that drop the drain after that fuse was removed, but apparently not? I guess it’s a cumulative drain across the entire car?

I just read about the double locking function. I will try that. Though my Powerfold mirrors are long since stopped folding.

An I missing anything?
I will check my testing/ charging Volts again on a moment and update.

14.43v charging
12.34v resting (after 4 days with the battery connected/ engine not been run/ boot lights on).

I have done this test on my car, and initially thought I had a problem as it did not achieve the 30mA stated in the workshop manual. The answer is to wait: in my case the car did not drop to 30mA until at least 45 minutes after double locking, switching everything off (boot lamps stay on for quite a while) etc. I watched it during the 45 minutes and it does get quite low, but seems to have a surge of activity to nearly 1A every 5 minutes or so before dropping down again to maybe 50mA. After I hour it should definitely be reading 30mA or so, but don't be surprised - even then there are little flurries of activity lasting a few seconds ever few minutes!

I have done this test on my car, and initially thought I had a problem as it did not achieve the 30mA stated in the workshop manual. The answer is to wait: in my case the car did not drop to 30mA until at least 45 minutes after double locking, switching everything off (boot lamps stay on for quite a while) etc. I watched it during the 45 minutes and it does get quite low, but seems to have a surge of activity to nearly 1A every 5 minutes or so before dropping down again to maybe 50mA. After I hour it should definitely be reading 30mA or so, but don't be surprised - even then there are little flurries of activity lasting a few seconds ever few minutes!

Good advice thanks.
I will try again as soon as the rain stops. I don’t want my multimeter to get wet!

My X358R is generally in use every day, but has been left unused but double locked for up to a month while away, without any starting or spurious message problems.
The XFR is used less frequently; never any starting problems, but after 3 weeks idle it gives a low battery warning if not fired up immediately upon entry.

There is apparently another danger on double locking though. Nothing is ever simple.

https://www.jaguarforums.com/forum/xj-x ... ng-117575/

If I don't drive mine for two weeks, I start getting familiar warning codes popping up. I also have a new Yuasa battery. Needs a charge for 5 hours and the codes disappear. Richard.

PS - I'll look into the solar charger.