2 weeks ago I got in to my s2000 and found the battery was flat. hadn't left anything on such as lights etc.

Took battery out, charged it overnight, and put back in the next day

Car has run fine for over a week.

Try to get to work this morning, and battery has gone dead again

Obviously I need to take it to a Kwik fit or similar to get the battery checked, but could the alternator be on the way out?

 

Doubt it, how old is the battery?

 

Not sure mate, car is 06, I've owned for 18 months and it's the same battery as when I bought it

 

I would say the battery was goosed then. They do have a life, and 6 years if it is the original is bloody good going!

 

Check what voltage is showing on the battery with the engine running to make sure it's charging properly. I'd say the battery is on its way out though

 

I will agree. I think your battery is dead and there no way to recover it

 

guys, cheers for the input, much appreciated

 

I'm still running my original battery on my 01 model - got a way to go to better the original battery on my 1996 Triumph bike

But then they do live on an Optimate charger...