Hello new member here with a charging problem on my trusty stype 3.0 auto 2002/2003, It all started 12 months ago with red alternator light on dash coming on intermediatey I have read the forum on this problem, and took advice bought the correct smart alternator, bought the silver calcium battery, cleaned earth points , replaced red lead from battery to fitting on side of boot, but am getting a battery drain over 3 days the battery is flat down to 11.7v won’t turn over, recharge battery away it goes, have bought a tester the battery in car is charging at 14 v so assume all is well with alternator, but battery still loosing after 3 days standing, did a drain test no problems there, so decided to buy a voltage meter that fits into cigarette lighter, and there I have found a problem when car starts I put meter on battery terminals and the charge is 14 v but the digital volt meter says 13v, and after 20 minutes of running the charge on the battery drops to 12v and the volt meter reads 11.8v so the flat battery is that whilst driving it stops charging, now if I stop and wait 3 minutes and restart the car it goes back to 13.6 at the volt meter for 10 minutes then drops back to 11/12V this happens every day , any thoughts please it’s driving me nuts and oh yes it’s been into 2 electrical technicians with no joy so help please if you can .

 

Welcome to the forum.

Lots of info to digest in your post. You mentioned the battery light was coming on intermittently, beginning about 12 months ago. Did you change the battery and alternator at that time, or was that more recent after putting up with the intermittent light for a while?

Did you change the battery and alternator at the same time? I ask because I'm curious if all was good for a while after changing just one component, but then it got worse after changing the second.

Are you still getting the battery light? If so, intermittent or steady?

You mentioned the battery running down after sitting for three days, yet finding nothing draining it. Two thoughts for that:

1) Try disconnecting the battery ground cable and let the battery sit for the three day period. Does it run down even if disconnected? That would point to a bad battery. If the battery holds it charge, that would point to an intermittent drain, something you were not able to catch previously.

2) Do you have another vehicle with which you could swap batteries? That would be a good low-cost way to troubleshoot.

For any further troubleshooting, make sure to first fully charge the battery. Don't count on the alternator to do it. Use a charger with at least a 10 amp output. A trickle charger won't cut it.

 

Good evening and Thankyou for your message,
To be honest this has been going on for 12 months and I went straight to the problem and missed several things out not to bore anyone, the fact is I have put 3 alternators on over a course of 7 months from scrapped stype cars, I have 3 battery’s in my garage I have bought over 12 months , the latest is a silver calcium , 6 weeks ago , a new smart altermayor, 2 weeks ago, the red light comes on when battery goes down to 12v whilst driving, then I know to change battery, the red light stays off until battery goes low, if I leave earth cable off for 3 days battery still charged, have put both battery cables together to get rid of anything unto old in system, saw on you tube to use a multimeter by disconnecting earth strap and putting both connections one to earth poll and one to strap connector, put the multimeter to 10 amp and check for a drain the screen is blank showing no drain, there was a bit more to the test but it was okay, I am puzzled that the digital volt meter shows one charge at the cigar lighter and the multimeter shows a different reading at the battery, have checked power cables going to fuse boxes good connections, no heat on cables anywhere, since the new alternator was put in things got better , the red light used to be on after 12 mins of driving , but I guess because they were from scrap cars it was a gamble how old they were, have tried pulling fuses but nothing different, have replaced some box fuses in fuse box but that made no difference, there is no yellow light on dash so no codes show except I have had low charge spring up before but not with this alternator, could it be the ecu turning charge off , ? Thankyou for your interest .

 

Keith: You almost always loose +/- 1V reading the voltage at the cigar lighter. The wiring is a much lighter gauge than that used to power the more current intensive electrical components on the car and the socket wiring is a fairly long run from the trunk/boot. I had the same experience when taking a reading with a plug in meter at the lighter socket and my charging system is up to snuff.

Are you sure that the alternators fitted are the correct spec for your car and are/were functioning properly?

 

Okay, I may have picked up a little clue here. I had never heard of a silver/calcium battery until just now. For those familiar with me, this is quite amazing, as I'm famous for knowing everything.

From the little bit I've just read, silver calcium batteries require a higher charging voltage than regular lead/acid batteries. If fitted to a car originally designed for lead/acid, the silver/calcium battery will be only be partially charged at best, which lead to a possibility of becoming sulphated. In layman's terms, the battery condition will deteriorate and lead to low system voltage, even though the alternator is working as hard as it can.

Now if you can tell me that silver/calcium batteries were original equipment, or approved by Jaguar as a replacement, then my theory is all wet. But for starters, I'd switch back to one of those other batteries in your garage if they are the correct type. Maybe have them tested first with a capacitance type battery tester. Any store that sells batteries should have one, and will typically do it for free.

So why didn't any of those batteries work? Perhaps you had two faults active at different times, a bad alternator AND a bad battery. When you were trying junkyard alternators, none of them were good, even though those batteries were probably okay. Then you switched battery types, to silver/calcium, which meant two problems active at once. Eventually you installed a new alternator (which is hopefully good) but now it's dealing with the wrong type of battery and can't properly charge it. That's why I recommend switching back to an original type of battery and see what happens.

 

Thankyou so much guys with interest to my problem, two of my batteries which are 15 months and 12 months old, and the silver calcium battery which was bought after reading on a jaguar thread that Jaguars were supplied with calcium batteries and that a lot of electricity problems was due to lead batteries being fitted , and after this guy did a lot of research this silver calcium is the bees knees, every time I change battery it immediately goes on to a digital charger and when fully charged shows 4 bars on screen, and multimeter shows 13.6v, the alternators in the past were all correct for car the numbers corresponded with the original, I bought a couple to try as they were only £25 each better than Jaguar price, read many times on the thread that battery light on car will stay on if wrong one for car , I never had that problem , it definitely seems the cars charging system is shutting down after approx 10 mins of driving , every time we use the car, the digital volt meter was a good buy as it tells me when the voltage drops from 13.4/13.9v to 12.2v so I pull over turn engine off for a few minutes start up and it’s back to 13.7v charging, strange thing is the battery light does not show until battery reaches 11.9 v well that’s all info that I can share, Thankyou for showing interest.

 

Good morning ,
took a reading last night of battery on car it showed 12.6v lead acid , this morning took a reading 12.35v is this okay is it a normal drop. Thankyou for your interest.

 

Sounds like you have a drain.

There are threads with details of finding how, especially measuring the (tiny) drop across each fuse.

 

This thread has some very good details of the process to find any drains, with different methods to measure them.

https://www.jaguarforums.com/forum/s...-drain-123535/




You previously mentioned two automotive electrical shops had tried to fix the problem. What did they find, and what actions did they take to correct it?