Battery drain over 2/3 days

[alleneng]

Hello, I have recently joined the club, and wanted to ask any members with S types, if they have experienced a drain on the battery ( 2 weeks old ) when the car is switched off. A clamp on ammeter is showing a 1.5/2 amp loss,inreasing to 14/15 amps for a second or two! I have pulled every fuse to try and pinpoint the drain, with no conclusion. The worse case scenario is a short to earth somewhere, of course, but I wondered if anyone had experienced this fault.
I have three four S types over the last six years,and I love the cars,and have been lucky with reliability. My car is a 2.5 V6 2003 MY
regards
allen

[J44EAG]

Allan,

Occasionally we hear of a leaky diode pack on an alternator. Leave over night having taken a battery terminal voltage reading.

Next morning take a terminal reading again having double locked the car overnight. Go to the alternator and place your hand upon the case. If it is in any way warmer than the general temperature of other components within the engine bay, you may well have found the issue.

If the issue exists then it might be worth consulting a good local auto electrician in the hope he may be able to salvage and rebuild the alternator and prevent current drain. That would certainly be cheaper than buying a new unit. If a replacement is needed, don`t discount buying second hand from a reputable breaker such as Eurojag. Details on the net or in our magazine.

Also ensure that you fully turn the ignition key to the left when removing the key from the steering lock when you leave the car. The ignition/steering lock can wear as the car ages and the radio can easily be left powered up. Also check to see that the battery terminal posts are fully tightened. I`ve had a couple of issues with that in the past.

Try that for starters.

Mike K

[alleneng]

Hi Mike, Thanks for your reply. Regarding the alternator, I disconnected both cables,on the advice of Bob Bate (who services my car ) and the drain remained, so I ruled out the alternator. Would this be correct? The charging voltage does vary between 13 - 14.5V
regards
Phil (allen)

[J44EAG]

Hi Phil.

Charge voltage always has to be about a volt higher than terminal voltage after a cold start. This progressively drops as the alternator or a decent mains charger brings the battery up to a pre-set level. The reason for this is akin to two water tanks linked by a pipe with a valve in the middle. Think of one tank having more water in it than the other with the valve closed. Then open the valve. The water will then flow from the high content tank to the lower level tank until levels in both tanks are the same. (Manometer effect) Get the idea?

If you have terminal voltage of 13.5 to 14.5 volts with alternator connected and the engine running, this would suggest the alternator is functioning correctly as regards charge ability. However it is worth leaving corrected over night and checking the alternator is not warm next morning. If it is, that would suggest a problem with the diode pack. (Unlikely I would think in this case)

If you have leads off the alternator (Never run the car in this state or the alternator will be damaged) and terminal voltage subsequently drops, you either have a time expired battery or there is some other drain occurring. Check that all cabin lights switch off when doors are shut and also check to see the lights in the boot extinguish when the boot is closed. I would suggest a battery load drop test be performed to ascertain battery condition. Testers are available on ebay for around £32.

Door lock solenoids used to be notorious for failing and causing current drain issues. Again check that all are functioning correctly. We don`t hear so much about that nowadays.

Mike.

[alleneng]

Thanks Mike, Being a mechanical engineer by trade, electrics are not my strong point. I'll try what you suggest. But it is very frustrating.
regards
Phil

[rosemary]

Hello All
In the last week I have had a complete battery drain over 1 day. Initially thought it was the glove box light which had fallen apart around the catch/light unit and fell into my hand when I opened the flap. Embrittlement of the plastic. Replaced the carcass and re-assembled the unit back in place. Fitted a new battery (fully charged) couldn't get the year old one to recharge, all was well for a day or so then the new battery became fully discharged. Fiddled about and recharged the new battery then fitted a Voltmeter and an Ammeter (in series) Readings were 12.84V and 2.74Amps with the car locked and all doors etc shut interior lights off, boot and glove box bulbs removed. I left the car in this situation for an hour, on return it was still reading the same i.e. 12.81V and 2.74 Amps. I cycled the Door Locks/Locking/Alarm a few times and current reading fell to 0.7Amps after about 10 seconds. Question ,1)What should the quiescent Amperage be about.2) Does the Alarm system have a fused supply.
Dave Hart

[J44EAG]

After double locking, it takes about half an hour for the computers to fully close down and get to the lowest drain state. If you unlock, then the system wakes up again and increased current state can occur.

I think you might have to start pulling fuses and noting which, if any fuse then makes a difference to amp flow. Two amps is quite a draw on a typical 90Ah battery. A radio left on over night is enough to flatten the battery.

I might have mentioned that a worn lock barrel can cause issues. The ignition key must be fully turned anti-clockwise before removal. If the lock is worn, sometimes the key can be removed in position one. That leaves the radio still on.....

Mike

[rosemary]

Hello Mike
Thanks once again for your prompt input. I checked the ignition switch fully anti-clockwise and had the radio turned off, read comments in your previous posts.
The 2.74 Amp drain stayed on overnight until I cycled all the doors individually this morning by manually locking them then unlocking with the fob I even cycled the fuel cap, once done I double locked the car and the initial sequence was (1) 3.31 Amps until interior lights went out. (2) 2.74Amp for about 10 to 20 sec to (3) ) 0.8 Amps falling to 0.7 Amps after about a minute. Initially when operating the fob I briefly saw a fleeting 8 to 9 Amps not enough to blow the fuse in my instrument. Am I looking at an Intermittent episode (sod it if I am), I am going to do what you have suggested in a previous post i.e. stop charging the battery tonight, currently (pun) showing 12.8Volt, leave it overnight and check Voltage in the morning.
Is a background drain expected to be about 0.7 Amp

[jeff1954]

Mike You mentioned about locking the car over night. My car is always in a locked garage overnight so I tend not to lock it. Would this cause higher battery drain?

Jeff

[J44EAG]

It could well do. Double locking is the best way to ensure lowest possible drain.

I recall David Marks mentioning this at one of the seminars.

Mike

[rosemary]

Hello Mike
Well I checked this morning and the reading is 11.75 Volts. this after 12 hrs from 12.8 volts. I think pulling fuses again might be an option but it hadn't given me a clue the last time I did it.
Dave

[Montana5]

One of the most common Battery drain places on S Types is the Radio. How are you connecting the measuring devices to the Battery with the Car shutdown.

Doug.

[rosemary]

Hello Doug
I am disconnecting the negative cable from the battery terminal, attaching a lead to the negative battery terminal to the multi tester (set to 10Amp range point) then the other lead from the multi tester to the negative cable connector terminal In other words in series. The leads are long enough to have the tester outside the car with the boot closed . the radio is turned off, the interior lights have turned off, and the car locked. The current drain is 2.7 amperes fluctuating .01 to .04 Amps. Yesterday after about 10 sec the drain fell to 0.7 to 0.8 Amps. Today the constant drain is 2.7 Amps. I was going to pull fuses again today but have lost the will a bit waiting for the battery to charge the up
Dave

[J44EAG]

I`d suggest pulling the central locking fuse as a start. The central locking door actuators have an unenviable reputation for faulting.

Just an idea.

Mike

[rosemary]

Hello Mike
Yes I know had the same thing with my petrol SE 7 years ago I was hoping against hope it's not a repeat, sold that car in exasperation and like an idiot bought another ie this one, hoping Jaguar/Ford had fixed it. You may recall I've had a new gearbox and loads of other bits a pieces with this car at great expense, although Jaguar in their embarrassment stood a bit of the cost. We are off babysitting for the weekend tomorrow so no more fun until we get back next week then I'll start again pulling fuses. In the meantime I'm going to disconnect the battery from the car and leave it, it's a good job we have a good old reliable German BMW Mini (never a single problem in 9 years and 108,000 miles) to get us to Shropshire.
Dave