So last night when I left work for home the RR would not start, battery turned it over once or twice but then nothing. I got it jump started easily off a old Ford focus so I knew there was some power in it!

Now during the evening all I used on it was the sound system plugged into the phono jack without the engine on. So my question is this , why did I loose so much power for it not to be able for it to start. Oh and it was about 8 degrees last night.

So the vehicle in question is a 2007 TDV8 and coincidentally i was on 99997 miles, so was it a warning to say i wont last past this now and will start going wrong?? There is a saying is that once they go past a 100K they start to break ! Or is it it just that my alternator is on its way out. The battery is less than 10 months old and is a YUSASA 900A.

range rovers have a habit of doing stupid thing's, when you were using your sound system half of the car would still be awake putting drain on the battery, if you have a relatively battery and no battery warning light I would be more inclined to suggest a battery drain somewhere

you can go to most battery suppliers and ask to have the battery tested for confirmation it's good

2007 TDV8's have weak alternators - thread here

That said - it sounds more like battery drain - you can do very little with the engine off before you've lost enough juice to prevent it starting.

A jump pack like a Floureon would be a good investment - thread here

my battery seemed weird for over a year, just seemed to only just start the engine. although it past all the tests at the dealer. Then it let me down, jumped it and was OK for weeks then of course let me done again. Jumped it got me home and booked it in. Had to jump it to get to the dealers and then it tested faulty. I just put it done to sediment shorting the plates. No problems now and turns over with ease.