Further to the above - thgis might also help....
How to find the cause for an slow draining battery
Many Land Rovers are plagued by the 'flat battery' syndrome, especially the newer ones. After some days of not being driven the battery is dead flat. Under normal everyday driving those sympthoms do not appear.
The problem is in most cases a slow drain somewhere. It does not take that much to empty even a large battery over 3 or 4 days. An simple underhood or interior light is more than enough. But how to find it?
First make sure your battery is ok and fully loaden. Even a new battery is sometimes faulty. Drive to your local parts store and have them check your battery with an load tester.
If this is ok make sure your electronics don't mind being disconnected. Ask your dealer or have a look in your owners manual. Elder petrol engines (except new shape RRs) and all diesels except the TD5 are no problem.
Disconnect the positive clamp on your battery but take care not to touch the body metal with the spanner when doing this.
Now connect an small light between the + terminal and the clamp. Put the clamp on a rag so it can't touch the sheet metal. If any drain is present the light will glow. Or you can check the amount of drain with an small ammeter. An drain of 300mA (0.3A) can be tolerated. Next pull the fuse for the clock and the radio. Still any current flowing (light on)? More details on current drain figures can be found here - Battery Drain - A few ideas
Ok, so you really have a problem. Now start pulling the fuses in the fuse box one by one until the light goes off. This is the circuit in which the problem lies. Check your manual or the indications in the cover of the fuse box to see which systems are connected to that fuse.
The next steps depend on the systems concerned. Try disconnecting each one of the parts connected in the circuit. Again it's the same - when the light goes out you've found the problem.
Even better than a light bulb is an buzzer. Many people have one of those annoying little rascals lying around. Use it.
In very new vehicles there are so many electric and electronic gadgets that problems are very common. Especially the immobiliser / alarm is known to be a can of worms. Those have best been left to an qualified auto electrician - not necessarily your Land Rover dealer.
