I have an unused 12v jaguar xk8 battery, that has never been in a car,
plan is to use it as a caravan 12v supply

So far it has not responded to a trickle charge, or a jump off the mondeo

is it fooked !!

Steve

Probably - a car battery can expire over time if it's not used and kept properly charged.

A car battery is also rubbish as a 12v supply - they don't like being discharged over a long period (you want a proper deep-discharge battery for that).

Probably dead, what is the voltage of the cells without load, if it's 12V or more you stand some chance. You also don't really expect good service from a car battery when used for deep discharge such as a caravan (car batteries don't like being discharged!)..

Dan

You need a 'leisure' battery to provide a power supply for a caravan.

I know i need a leisure battery, but we have just part exed the old caravan, and they are not having my new £120 battery!

so i was trying, to use "one in stock" just to part ex


Steve

Is a sealed non serviceable one? You maybe able to test the cells with chemical pupet thingy and or change some liquid.

I use to "drop test" the old car batteries. Basically i used a snap on battery tester and shorted out the terminals untill i lost my nerve. It shapes up the liquid and often brought it back to life.

They have also exploded in the post straying liquid everywhere. Be careful!!!

I had one that was completely flat, intelligent charger/maintainer said it was dead stuck it on an basic old charger and charged up fine.

Adding some Ethylenediaminetetraacetic acid (commonly known as EDTA) into the cells
can break down the lead sulphate build up and give some extra life. But if the plates have
warped and are touching each other then it's fubared. Sadly this is likely to be the case.

Even bog standard lead-acid chemistry batteries won't take a charge if truly dead flat they fight the currrent getting pumped in often need to be connected for several hours (12+) to a standard charger before the internal resistance comes down far enough for the battery to start to slowly take charge.

Most smart battery chargers won't look work on dead flat batteries.

Of course modern enhanced chemistry batteries won't accept charge easily if dead flat anyway.

How old and unused is it ?
Are we talking months years or decades?

As mentioned it may need to sit on an old fasioned charger for a good while before anything starts to happen?
I'm of the "I have one in stock" camp too , if you can get it going

otherwise down to the scrappy and get the cheapest battery they have. Bear in mind they fetch a few bob in scrap these days too.....
Or if your car battery is getting long n the tooth/not as good as it was buy a new one for the car and pop the old one in the van.

edit. Or try fleabay. Cheap batteries turn up locally, probably get one for less than scrap value (seems to be £5-10 last time I took one in)

[Edited on 17/9/12 by cliftyhanger]

Your battery will be a brick of lead sulphate, if it's been dormant and discharged for a length of time.
EDTA will 'revive' a lightly sulphated battery, but it's unlikely given the high impedance you clearly have, i.e it's dead.

Weigh in your lead sulphate brick and buy a new one.

My optimate charger revived a battery which I had replaced on my Nissan van and it ran on my daughter's Corsa for a couple of years and was still working when it was sold.

I let the bike battery on the MK run flat last winter, a tip on a bike forum was to "flash" the positive battery terminal with
a car charger, up to 10 times, then connect an Optimate type charger. And it worked. Although it doesn't hold a charge for more than a couple of days.

Bike batteries are a LOT less tolerant to sitting doing nothing.
Presume to the small size means that the plates fur a lot easier