Lost electrical power after battery recharge
 

Hi - 9'I am a new owner of '96 XJS convert, and new to forum. Did not drive it this winter and let battery die. Recharged battery and car started fine. Shut off ignition and when I returned several hours later, engine turned over once but failed to start. Second attempt - nothing! No power to anything but dash clock. Briefly recharged battery, and in doing so, found negative battery terminal very loose and tightened. No other issues (corrosion, etc.) but even though battery seems to hold charge (it may indeed be 5-6 years old, but have not removed battery and checked date), I cannot get power to any lights, radio, fan, and only dash clock continues to run. Starter will not engage - battery has full charge. Ideas? Just wondering if there is some special technique or “jagquirk” in play here? Thanks in advance for any assistance!

Check this thread from earlier today (similar issue):

https://www.jaguarforums.com/forum/x...-crank-216266/

https://cimg7.ibsrv.net/gimg/www.jag...80d51d1f0.jpeg
Thanks ... there does seem to be an additional component or two near the battery - including the red/white cube on the positive lead - will work with tomorrow. Appreciate the pointer to the other post!

Ok - looks like the small 8 amp charger I used may have damaged the electrical system, since the manual states that the battery must be completely removed “if a high-speed battery charger is used”. Anyone have any ideas on how bad this could be?

Hi UDATDERE

It may not be 'Game Over' although I think you are going to kick yourself for not knowing about that 'Green Knob' on the Battery or else I'll have egg on my face for getting this wrong

But I am 99.9% Certain! That the 'Green Knob' on the Battery is what is known as a Battery Discarnect (ebay about £5) a fantastic piece of kit! more commonly known as a Battery Isolator (I've got these on all my Cars and they are Amazing!)

Anyway lest I digress, if you had know what that 'Green Knob' was and undone that 'Knurled Knob' a couple of Turns, then it would have disconnected the Battery from the Car without having to take the Terminals off

Or else having to remove the Battery for Charging, also with that 'Green Knob' undone your battery would very likely NOT discharge itself if for instance left unattended during the Winter

Where the 'Clock' or 'Alarm' or a Leakage to Earth, could run your Battery Flat

All my Cars are fitted with these and having not been Started or even had the Battery Charged or even taken off the Car during Winter, as soon as that 'Green Knob' is Screwed Back In, the Cars always Start 'on the Button'

Also acts as an extra 'Anti Theft' device, because unbeknown to a Car Thief your Disconnected Battery is also locked in the Boot/Trunk, which is very handy if you have to Park your Car somewhere for any length of time (example Airport)

If 'The Jaguar Gods' are with you, maybe that 'Green Knob' just needs doing up a little bit tighter

(Not 'Stupid Tight'@Grant Frances) but just a little bit tighter and only by Hand

When disconnecting the Battery with this 'Gizmo' you don't need to take the 'Green Knob' off, as all you need do is undo it a couple of Turns

Other than that you may have disturbed or even blown a Fuse in the Fuseable Link

https://www.jaguarforums.com/forum/x...-crank-216266/

https://cimg5.ibsrv.net/gimg/www.jag...2e358303c5.jpg

One Gadget I'd never be without, the Amazing Battery Discarnect (all over ebay about £5)

Wow! How informative! Thank you, Orangeblossom - what a nice response to wake up to this morning! Unfortunately, the green knob was tight, although I loosened and re-tightened with no affect just now. Battery still holding strong. I also flexed the fusible link to no avail. Do I take it that the fusible link may have been blown by my activity, and that I may have only to replace that? I will research that process here. Finding this forum is a blessing!

UDATDERE,

I would suggest a couple of things:

Check the battery voltage again with the leads connected. If ok, check the battery voltage using the bulkhead terminals (There are both positive and negative terminals there.)

If you're not reading full battery voltage at the front bulkhead terminals, remove your Discarnect attachment and put the original lead back on the battery post. and check bulkhead voltage. I know you've mentioned that you screwed down the Discarnect knob but I wonder if there is still a contact problem.

Good luck

Paul

Hi UDATDERE

When you eventually get your Car running that Battery Isolation switch will prove to be so useful that you'll wonder how you ever did without it

From a 'purely personal point of View' I would never Jump Start my Car, or try and Charge the Battery unless the Battery Discarnect (Isolation Switch) was first turned off, or one of the Battery Leads was disconnected

Just in case an electrical 'Spike' blew the diode in the Alternator and while some say that can't happen, well let's just say I'm Paranoid and as such not taking any chances!

If your Battery is getting old or may have been used and abused in the past, then it might have a 'Dead Cell' as while a Meter may show it up as being Fully Charged, that 'may not' be what happens when you put it under load

Like for instance trying to Start your Car!

As such the first thing I would do would be to try a Battery from another Car you know is good and if that solves the problem, then treat yourself to a Brand New Battery

Nothing more embarrassing than owning the 'Swankiest' Car on the Road, especially if She won't Start! been there done that and don't want to do it again!

Your 'No Start' Problem could be down to quite a number of things

Maybe a duff battery, that won't hold its Charge under load or maybe you've blown a Fuse in the Fusable Link, or the Spade Connector in the Fusable Link need to be taken apart for a really good clean before being put back together

Though having said that a lot of Electrical Problems could be down to something like a bad earth, so clean the earthing Terminals on the Left and Right of the Closing Panel, that goes over the Top of the Radiator

Then do the same with the Earth Wires that are bolted to the Fender/Wing up near the Battery

I doubt if its anything serious, so take the advice of others who know more about Auto Electrics than I do

Hi UDATDERE

These are the 'Bulkhead Terminals' that 'Paul' was talking about (see Photo) The Silver one is Positive and has a Rubber Cover over it

Don't take any notice of the other Stuff, as I was just experimenting with an Electric Fan

https://cimg4.ibsrv.net/gimg/www.jag...c0803d5a8f.jpg

https://cimg7.ibsrv.net/gimg/www.jag...e3eb857c96.jpg

The Positive Bulkhead Terminal has a Rubber Cover over it

That is great to hear, Orangeblossom! I am going to call in a second (local) brain and set of hands - but getting quite an education through your responses and those of others. Loving this forum almost more than the car. I made some progress today when I jiggled the fusible link again and I momentarily regained the courtesy lights, but lost them again when I attempted to start car (with no solenoid/starter engagement. After that, I noticed some erratic clock movement - second hand pausing - and for a brief period after that, with the key removed, heard a faint ticking under the dash near steering wheel almost like fuel pump relay noise, maybe. Will also follow the suggestions re measurements in the engine compartment, but have not yet located the main terminals there. Ah, ‘‘tis Springtime, and the Cat wants to roam! So do I! More movement of cables has returned courtesy lights and starter solenoid noise, so I am making progress, and beginning to strongly suspect loose or poor connection(s)!

https://cimg0.ibsrv.net/gimg/www.jag...527874e2ad.jpg

The 'Twitchy' Fuesable Link (Do not disturb!)

Hi UDATDERE

'You've Cracked it!'

Your Problem is almost certainly down to that Fuesable Link (see photo above) and so take off that Battery Lead and pull those Spade Connectors apart and really clean everything up before you put it all back together again

Then when you've got your Car Working, as I'm sure you will, then don't even think about moving that Battery Lead, just in case that 'Super Twitchy' Fuseable link decides its time to go on the rampage again!

Don't give up, you're nearly there! 'Well done!'

I use the battery disconnect on my 96 all of the time. My first one went bad and even with the knob screwed all the way tight, I still did not have power to anything. I thought I had fixed it, but heard a clicking noise under the hood while the engine was running. Turns out the switch was intermittently making and breaking contact. Luckily no damage was done. My advise would be to purchase a new disconnect switch.

Disconnect battery. Jumper cables from a friendly driver onto the battery cables of your jag. Try it now.

Starts or tries, get a new battery. No start, no try, reconnect battery and repost.

I drove Her Highness to the gas station, shut her down and that was it. Tried to restart and got nothing, not even a click. Thought it was the battery, which was indeed flat, and she would start on the charger but would immediately quit when it was disconnected. Turned out that the problem was with the recently (and poorly) rebuilt alternator. You might check yours while you're at it.