Fix Your Stuff Community Store

2.3GHz, 2.6GHz, or 2.7GHz quad-core Intel Core i7 processor (Turbo Boost up to 3.7GHz) with 6MB shared L3 cache.

561 Questions View all

Options

How to make sure I'm using the full battery capacity?

Hello,

I’ve recently got an official ifixit battery repacement kit for my MacBook Pro 15 retina mid 2012.

On the product page it’s written: “New battery guaranteed at capacity greater than 8250 mAh.“

I am currently struggling to keep the mAh value at 7900 when full. Which is nowhere close to the guaranteed advertised capacity.

What I’ve tried:

Resetting the SMC.

Various tries and small variations of: charging the mac to 100%, leaving it for a few more hours to charge at 100% then disconnecting the AC until the mac dies, leaving it overnight (and even in the morning for a few more hours to make sure it’s drained), charging it fully, a few more hours after it’s 100% I still kept it plugged in, then another full discharge, charging it again and using it normally.

^I’ve done this a few times with slight variations, sometimes throwing the reset SMC before the process sometimes after, after discharging it sometimes even pressing the power button once in a while to display the low battery indicator, I figured it would drain the battery faster, before setting it to drain overnight, etc. All sorts of variations of these processes.

I am currently at 27 cycles, still trying to get to that advertised >8200 mAh

I am using the mac’s system info to see the battery stats as well as a program called battery monitor, which for example indicates to me in its UI:

current charged: 100% (7896mAh) | battery capacity: 93% (7899mAh), once I’ve gotten this battery capacity number to be about 97-98% and at about 8200mAh, but the next time I charged after that it fell into about 7600mAh range and I’ve since reset a couple times and gotten to where I am now.

The hints that I got throughout this process point me to think that there is more space in the battery to hold more charge but somewhere along the line the Mac internals / the controller on the battery simply think it’s maxed out and stops charging it to its fullest, any ideas on how to fix this?

EDIT: I am also using a new & original apple magsafe 2 power adapter with this process, it’s 100% original 85W in this quest, so I don’t think it’s because of that.

Answer this question I have this problem too

Is this a good question?

Yes No
Score 0
1 Comment

Would also like to add that between resets I’ve mostly used it normally for about one week since it’s my work machine, then resetting it in the weekend in a slightly different way than before. So I guess I’ll leave it for about two weeks or so of normal use as @danj pointed that it would need more time to calibrate itself to its max limit, and see if the limit is higher than what I started out with right after the reset. I think if after > two weeks the mAh value won’t go up by more than 100mAh (anything under that I would consider variations) it would be safe to conclude that it’s ether a measuring issue or the battery is not quite as advertised, I fail to see other meaningful explanations to this.

by

Add a comment

1 Answer

Filter by:
Most Helpful Newest Oldest
Most Helpful Answer

Options

Lets use an analogy to help explain things…

Lets say you have a new dried out sponge nice and stiff like a pice of cardboard! Now you have a quart of water and you put the sponge into the bowl with this water how much of the water will it suck up without touching it? Squeeze out the water into a measuring cup. Now this time let is soak up a new load of water how much did it suck up this time? Did you see the second time it held more! And if you do this one more time you’ll see it will be a bit more than the second time.

So the exercising of the sponge allowed it to absorb more water.

So now lets also look at what you have after your’ve squeezed out all of the water is the sponge is it stiff like a piece of cardboard? No! As there is still a bit of water still present in the sponge which you just can’t remove by squeezing out. There will always be water in the sponge until it air dries.

So lets get back to your battery issues…

A battery is nothing more than a sponge! In this case it’s the storage of power Vs water! And just like a sponge over time the constant squeezing out of the water wears the battery which is the cycle rate.

We really don’t want to squeeze out every last electron out of a LiOn battery as that forces the battery into a deep charge cycle which is one life cycle! Instead we don’t want to let the battery get that low so you get the most out of your battery before it needs to be replaced. While thats easy to say, a road warrior doesn’t always have access to an outlet to charge the system or able to stand still long enough while the system is charging.

  • If you can get a car/plane charger so you can charge your system on the go as you’re in your car or in flight.

So where does that leave us conserve your battery as best as you can by not letting the battery charge to go to the red point (I try to stay above 1/3 charge level) and if you can always top off the battery. Unlike NiCad batteries LiOn batteries don’t have a memory issue so you will get a full deep cycle when you need it, but! As you deep cycle to many times the amount of storage of the full deep cycle will be reduced! Your batteries cycle count is 1000 before it can’t offer 1/2 - 2/3 of its charge capacity.

The gages you are using don’t have the level of precision I think you are expecting! So don’t be so literal with your measures. Your system needs to find the new batteries limits over time with use it will do this. You can speed up the process by calibrating the battery but you will loose one to two cycles doing that.

So the bottom line here your battery is fine!

Was this answer helpful?

Yes No
Score 1

1 Comment:

Right, thanks for the answer! I know this is not a deal breaker (would reather buy from ifixit than a random chinese seller from aliexpress or ebay), but nevertheless I was/am expecting to see that advertised max mAh now since it's still "new", else the description of the product from ifixit is plain inaccurate.

You are right in the sense that the measuring I took might not be accurate, I will open it up and put a meter to that battery after it's charged fully to see if the reported value by the mac is accurate.

I get that it calibrates itself in time, in fact I've been doing this thing for 3 weeks now, mostly trying various combinations of normal use + resetting the battery in the weekend, using the laptop normally throughout the week.

The fact that I only once reached the advertised charged capacity and then it couldn't reach that anymore in the next charge leads me to believe that ether the measurements are inaccurate, I'm resetting it wrong or the description of the ifixit product is inaccurate.

by

Add a comment

Add your answer

alex n will be eternally grateful.
View Statistics:

Past 24 Hours: 0

Past 7 Days: 0

Past 30 Days: 1

All Time: 386