Hi,
Recently I noticed a bit of an odd thing on my 2002 XJR. I keep it in the garage and normally I always put a trickle charge on it. I don't use it much, so sometimes it might sit idle for 4-6 weeks. So starting is never a problem, at least not from a battery point of view.

A couple of weeks ago I had parked my car and for some reason had not hooked it up to the trickle charger. When I did try to start it, after maybe a week or so, it almost did not. The starter motor was really struggling. I drove it for a trip to Belgium for two days. Parked it, check the battery voltage after an hour or so, 12.6V. I did not connect my trickle charger. This morning, after nine days, I checked the voltage, only 10,1V left at the battery. No way that was going to start a V8 of course. So I jump started it and drove over to the next village. There is alternator/battery/starter motor specialist. He tested my battery and the battery was absolutely fine. It is about three years old. Its a Varta G14 12V, 95Ah, 850A.

So the battery is fine, gets charged fine, when driving.

So this afternoon I decided to check for any possible parasite drains. I know all about the shut down times of the various system. I have a little table which shows just about every Jaguar and its shutdown time and subsequent quiescent drain. So the normal drain, Guess what model is not shown in this table, mine the X308.

I hooked up my multimeter to the battery, closed the car up, including the boot (careful with those test leads) and waited. So eventually the current bottom out at about 55-57 mA. This was after an hour and fifteen minutes.

If I compare to the values for other Jaguars it is a bit on the high side. But I don't think it would drain a good, well charged, battery in only nine days.


So a couple of questions.
1 Does anybody have the system shutdown time and the quiescent drain value for a 2002 X308?
2 Any thoughts as to what I am measuring (0,055 mA) and why the battery would drain that much in only nine days?

Thanks

Jeroen

 

The X308 should come closer to 31ma at rest in 'sleep-mode'.
That is the most common reading I have gotten over the years.

I have 5 running Jaguars and some of them sit for extended periods.
I installed battery cutoff switches for those cars.

 

One or more of these may apply

 

Thanks gents!

I read through these documents. I had not realised the car needs to be locked for this measurement. I will give it another try see if I get a different reading.

jeroen

 

What's the voltage reading with the engine running? I ask because ...

A couple years ago I was on a two-week vacation trip and on day three I started getting random electrical issues. It started with all nine P03XX codes, moved to IAT2 sensor, then P1121, and back to the P03XX codes. The car was running fine, but this stuff was freaking me out. I had two scanners and a tool box with me and did a little work at my bro's place (cleaned the spark lug leads and IAT2 sensor lead) but the problem was still there. Made it back home and went over to a neighbor that's an electrical engineer that used to work for Mallory. I plugged in my Autel scanner, turned on the engine, and the first thing he said was, "Your alternator's out." He actually looked at the voltage reading which is always there on the Autel; I hadn't even noticed that it was there. It would have been a lot better trip if I had. The voltage was at 12.6 with the engine off and didn't change when I started the car. It should be at least 13.5 to run all of the electronics. Replaced the alternator and all was good.

 

I've spent some time over the last few months tackling a similar issue on my 2000 XJR and would need to charge the battery every 2-3 days if not left on a trickle charger.

I ended up replacing both seat controllers, one front door controller, one rear door controller, SLCM and BPM. Seat controllers and door controllers can be taken out of circuit by removing their fuses and you then see what effect they were having on the overall draw. SLCM and BPM are harder to test but were cheap enough to just replace them. The last module I changed was the BPM and I'm now consistently seeing 25mA after the one hour shutdown time. I paid between $10-$40 shipped for each module on eBay, less than the cost of a new battery in total and each one incrementally improved the situation.

 

You can test which circuit(s) are still live using tiny voltage drop across each fuse (web search for details/videos).

As you test, do nothing that will wake more modules or you'll have to wait 30-45mins for them to shut down again.

Defeat door open etc switches.

 

Thanks for all the replies. I did the test again, now with the doors locked and alarm armed. Did not really make a difference. Still getting about 60 mA.

I forgot, I wrote a little article on how to deal with parasite drains sometime ago.

https://www.team-bhp.com/forum/techn...ml#post5440793

I did a bit of testing on the Jaguar then too as you will see. Current was 47 mA then.

I will start looking into this problem sometime in the near future. Even at 60mA it is not an immediate problem. But I would like to get it sorted sometime.

Jeroen