Battery drain on XK's

[WULLIE4567]

Hi folks
This may help some of us with XK8 batterys going flat if the car is left sitting for a week or so. So bare with me please while I try to explain.
I had a problem with my XK8 2000 model, If I left the car sitting for 4 to5 days the battery went stone dead after a charge it was fine if I used the car every day. Then the battery packed in. I fitted a new battery two month ago and had no further problems until last week, again she had sat for a week flat again. After charging her again she started no problem but I noticed that the blue LED bulbs bought from e-bay (illegal but nice coulor) were glowing. Every school boy knows that LED bulbs use much less power to light up whereas a normal 12 volt 5 watt bulb needs more to light up. 'Ah ha' talking to myself, have I found the reason for my cars battery going flat?? I got my meter out and checked each side light holder 8.7 volts running to both front side lights all the time ( side lights not turned on when testing) strange. I get the usual 12 plus volts when switching on the side lights. I checked the tail lights no power sneaking through to them only to front side lights. I have removed the front side light bulbs for the moment this should break the circuit and will investigate the problem further, there maybe a relay or somthing not switching off properly. Dont know at this stage.
Has anybody else noticed this or know about it, if you have the same battery discharge problem remove your front side light bulbs and check with a meter if there is power when there shouldn't be.
Let us know how you get on.
Cheers
Wullie.

[mike020150]

Several circuits within our cars are live for up to an hour after switching off. So, the way to measure battery drain is to connect a suitably hefty ammeter in series with the battery. With the meter wires outside the car, lock the car with the remote, go away for an hour and then return to check the reading. It should be less than 30 milliamps. This won't tell you which circuit is at fault but it could confirm or repudiate your initial diagnosis. If there's a problem the size of the current flow should help determine which type of circuit it's likely to be. Mike.

[WULLIE4567]

Hi Mike
Thanks for the reply, just back from a nice cruise, so just checking my xk8 form. I have a multi-meter I could use for this, I assume you mean disconnect the earth lead connect one lead to the battey the other to the earth lead, then take my readings, I did previously pull the fuses out one by one and when I got to the body processor fuse, the side light with the l.e.d bulb went out but this knocks everything out. I will connect my meter up tommorow and let you know how much drain I have.
Cheers
Wullie.

[WULLIE4567]

Hi Folks
As Mike suggested I tested the drain on my battery. After work today I disconnected the earth lead and connected my multi-meter black lead to the batt post and red lead to earth strap, boot now closed alarm on switched meter on to 200ma' position, it read 51ma for 5 mins then dropped to 40ma for 5 mins then 28ma for about 15 mins then stablised at 12ma, I think I have an intermittent fault because this 12ma reading would not drain the battery in a week. Maybe after it sits for a while it will start to drain at a higher amps, I will have to keep checking it.
If I unlock the car then lock it again the above happens again I tried this five or six times it always settles back to 12 milliamps.
Note the L.E.D side light bulbs I fitted recently stay dimly lit until it settels back to 12ma's then they go out. Also when I went on holiday for two weeks I disconnected the battery, when I got back I tested the battery, it read 12.6 volts when connected the car started well. If I had left it connected she would have been flat as a pancake.
Mike do you think the above is normal (the top part )? any suggestions?

cheers
Wullie

[mike020150]

Hi Wullie, If anything the current flows look quite light!
As you say, perhaps there's an intermittent fault. Otherwise, however unlikely, it only leaves the battery as being suspect. I'd try leaving the car for 4/5 days and then repeating the current flow test to see if anything's altered. Mike.

[WULLIE4567]

Hi Mike
Yes will try this next week, I put the car in the garage today to polish her left the meter on it and one time during the day the meter went from12 m/amps to 35m/amps for about 15 mins, then back to to 12, I didnt open any doors just polishing it. strange, the car was unlocked all day alarm off. will check again next week. thanks for your help and have a nice xmas and new year.

cheers Wullie

[joejag308]

One way to combat battery drain is to fit an in line charger and plug it in when you are not using the car..........this keeps the battery topped up permanantly and turns off when the battery is full it is a full charger as well as a trickle charger.......the top one for about £48 is the CETEK XS 3600.........very useful tool.....Joe

[WULLIE4567]

Thanks for that Joe might just do that.

Cheer
Wullie.

[mike020150]

Yes, these trickle chargers make excellent suggestions for Christmas presents! Mike.

[painter]

I've had ongoing problems with battery discharge. ok for up to a week but after that pretty flat. Had a real brain teaser yesterday, no power after app. 2 weeks, (not even a glow when turning on ignition) so assumed battery flat, and added problem of not being able to close the door as no window op. Had to leave car covered in pouring rain with door open and buy new battery.
Fitted new battery, no power - completely dead. Then penny dropped and thought of isolater switch, had been triggered by gale force winds. Hoping my theory was correct, as I now had both doors open and no window op., I reset and thankfully after connecting the alarm sounded. (on this occasion 'music').
Gave a run approx. 20 miles and gearbox fault code came on, only picked up 3rd (or 4th ? gear) After limping home waiting till tomorrow now to see if it still appears or drives norm. Hopefully this will be an ECU issue as car seemed quite damp under bonnet. Fingers crossed or trip tp Portsmouth. Glad I kept the Saab for everyday use

[WULLIE4567]

O' dear, have you found out whats wrong yet, keep us posted, hope you get it sorted out soon.
cheers
Wullie

[painter]

All sorted,
trip to MD to check fault code and gearbox performed A1 there and back. Fault code was identified as an 'unusual one' but clearly not a mechanical fault in gearbox. Possibly damp connection of transmission loom to ?ECU - (have read a post somewhere and this has been identified as a problem).
I guess the answer is to keep the car in the dry (garage) during winter to stop damp ingress, which must account for quite a few 'false alarms'.
(the battery never was flat, it was a tripped isolator, so have a spare battery now).
For all the niggles, I don't care. When the car is up and runnng it is worth all the problems and a few more

[outoftowner]

I used to keep the alarm on with the Jag in the garage but like others and, with not a great deal of use as it's a 'weekend car,' I would find the battery had drained, not flat but down enough not to have enough power to start the engine. These modern engines don't turn over slowly (and so might just start) do they, it's a case of all or nothing as far as battery power is concerned, either turn over and start or just a solenoid click. I now don't bother with setting the alarm on the Jag, I just lock the garage door and park the old workhorse of a Peugeot 405 on the open drive in front of the Jag, this (the Peugeot) is well locked with gear lock and steering wheel disklok on. The battery lasts much longer with the only drain being, as far as I know, the clock working away.
The bedroom looks over the garage with the Jag in. I also own (or he thinks he owns me, and he's probably correct in his thoughts,) a rather enthusiastic West Highland Terrier who sleeps near and sometimes on the bed and hears anything outside, even it would seem, before the sound is made, and of course then barks his head off! So problem solved.

[PrideofLyons]

What does your insurance fine print have to say about overnight parking/anti-theft arrangements? Just a thought - wouldn't want to find yourself without cover if the worst were ever to happen, and insurance companies are notorious for their ability to wriggle out from under.

[outoftowner]

Yes point taken, but in my cicumstances as in post I really think I'll continue as am, and have been doing, very small chance of theft, keys are kept well away and of course there is always plenty of power in the battery for starting when I need it, thanks for your thoughts though, Tony.