2012 Retina Macbook Pro gets 4hrs of battery life.

[Woodcrest64]

My 2012 Macbook Pro Retina 15" gets approximately 3.5 to 4.5 hours of battery life with primarily web use. The original battery life was rated up to 7 hours. However I've never achieved 7 hours of web browsing.

Currently my battery is at 649 cycles with 79% (6751mah) of the original capacity of 8,460mah. When I got the Macbook Pro it came with Lion which I've upgraded every year to the newest OS but though the performance has gotten a little better I've never achieved the 7hrs as mentioned.

I'm wondering now on Yosemite if I purchase a new battery if I will get 7 hours of web browsing assuming i don't watch a lot of videos. I know it depends on a lot of variables. I use to get around 5.5 hrs on the original battery.

Correct me if I'm wrong but if I do the math correct depending on my usage I should only see 6 hours at best if I replace the battery.

 

[Kissmyne]

It is difficult to make any assessment related to potential battery life as there are a great many variables. To give you an idea.. under the heaviest loads I can deplete my battery in 1 hour, under typical lightest loads I can get 10 hours. If you replace your battery I would expect very similar battery life as you are getting with your original battery. However please keep in mind that in my experience OS X 10.9 or newer has better battery performance than OS X 10.7.5 Lion. If you are running Yosemite, I recommend updating to El Cap as there are notable performance improvements that may also reflect on battery life...

 

[iliasp]

Replaced mine on my Mid2012 rMBP a couple of weeks ago (around 60% health after almost 800 cycles) and i am still getting around 3-4 hours, no luck there

 

[T5BRICK]

Battery life is highly dependent on usage. The number that Apple quotes is just an example based on a set of tasks. If you do a different set of tasks, it'll give you different results.

A replacement battery will help but nobody can tell you how much. It depends on your usage.