Many Mountain Lion users have been reporting that the operating system upgrade has lead to a noticeable drop in battery life on their MacBooks, and it now appears that Apple has been calling those affected to investigate the problem.

A poll by Engadget shows that more than 8,000 (43 per cent) of the 18,939 respondents that had downloaded OS X 10.8 Mountain Lion noticed a difference in battery life right away.

A second poll from Razorianfly showed that a huge 77 per cent of respondents are experiencing shorter battery life with Mountain Lion. The poll also revealed that the problem is most common on 2011 MacBook Pro models.

A thread on Apple’s Support Communities, which was started on the day of Mountain Lion’s release, is now 31 pages long with more than 450 replies and 27,000 views, indicating that the problem is widespread.

One user on Apple’s forums said: “I can visibly see the battery draining. In fact, when I first started writing this post my battery was at 96 per cent and now, three sentences later, without doing anything else, and without having any other applications running, my battery life is at 91 per cent!”

Some users decided that they would downgrade back to Lion, only to find that Apple had removed the older operating system from the Mac App Store.

On 2 August, users began reporting that Apple has been investigating the problem by sending out logging software to those experiencing battery life problems, and also sending out email questionnaires about usage to try and find the route of the problem.

Similar problems occurred with Lion when it launched last year, resulting in a 177 page thread on Apple Support Communities. This problem has yet to be resolved for some users.

See also:

Troubleshooting Mountain Lion
More than 50% of Mac users have upgraded to Mountain Lion
Mac OS X 10.8 Mountain Lion review
Mountain Lion downloaded more than 3 million times