I know there's been lots of threads about MacBook battery life etc, but I didnt notice anyone describe the issue the same as what I am seeing - but i apologise if i missed some threads on this. I have an 18 month old MacBook, which is plugged in to the mains most of the time. I let the battery run down now and then, but its only had about 40 cycles. The problem isnt the battery life, although it is pretty low, the issue is that it shuts down with no warning at around 40-50% - and this only takes about an hour! When i plug it in and start it up it still says 50% coconutbattery says it has 85% capacity So what is meant to happen? I have never had any low battery warning in all 18 months of ownership. 1 hour of light web browsing isnt very good really!