rMBP Battery Life?

[anatolie]

I've had my rMBP since the start of July (2.3/16GB/256GB) and my battery health has always been at 98-98%. I left it in my car yesterday, it was fairly cold outside, and when I went to bring it back into my house, the thing was insanely cold, which leads to my battery life problem.

I checked my battery health after the cold weather (and I know that cold weather has an effect on battery life), and it dropped from 98% to 85%! Is this big of a drop absolutely normal for cold weather? (-5c outside)

I booted into Windows and ran some testing/benchmarking software to stress the battery and drain it, and it seems that now it's back to 98% after the drain, is anyone else noticing issues like this, is it normal?

 

[simsaladimbamba]

Fluctuation in battery health is normal. My health jumps from 97% to 94% to 87% to 96% to 94% and currently 91%.

______________________________________________________
This should answer most, if not all, of your battery questions:
Apple Notebook Battery FAQ by GGJstudios
The F.A.Q. includes the following topics:

• BATTERY INFORMATION
• BATTERY LIFE FROM A CHARGE
• AC POWER
• CALIBRATION
• BATTERY LIFESPAN
• CHECKING STATUS AND HEALTH
• CHARGING
• WHAT IS A CYCLE?
• BATTERIES ARE NOT COVERED
• BULGING OR SWELLING BATTERY

______________________________________________________​

 

[lebbeus]

mine is only 3-4 days old and is currently 102% I can't imagine that lasting!

out of interest how many mAh is other rMBP users getting from their batteries? Mine reads 8641mAh at full.

 

[anatolie]

mine is only 3-4 days old and is currently 102% I can't imagine that lasting!

out of interest how many mAh is other rMBP users getting from their batteries? Mine reads 8641mAh at full.

My health is back up to 100% (using iStat, it's not always accurate), this is what I got from System Information:

Charge Information:
Charge Remaining (mAh): 8243
Fully Charged: No
Charging: Yes
Full Charge Capacity (mAh): 8549

105 cycles on the battery so far, people reported staying at 95-100% for their first 300-400 battery cycles.

What program are you using to monitor?

 

[GGJstudios]

mine is only 3-4 days old and is currently 102%

My health is back up to 100% (using iStat, it's not always accurate), this is what I got from System Information:
105 cycles on the battery so far, people reported staying at 95-100% for their first 300-400 battery cycles.

What program are you using to monitor?

Use iStat Pro (free) or iStat Menus ($16) to get accurate readings of your battery, temps, fan speeds and much more. It's as accurate as any app.

It is perfectly normal if your battery health (maximum capacity) is more or less than 100%, even when brand new, or if it fluctuates up or down over time. For further details, read the CHECKING STATUS AND HEALTH section of the following link.

The link below should answer most, if not all, of your battery/charging questions. If you haven't already done so, I highly recommend you take the time to read it.

Apple Notebook Battery FAQ​

 

[lebbeus]

Pretty similar figures.

What program are you using to monitor?

I'm just using a free app called battery guard. it gives the same info as 'about this mac' but sits on the menu bar.

The other 2 useful apps i find are 'brightness slider' which lets you drop the brightness real low if really want to squeeze the battery, and gfxcardstatus, to force integrated gfx.

 

[JohnDoe98]

I'm jealous, my battery is always hovering between 8000 and 8200, more often than not around 8000. When it was new it had over 8700 charge. It's been this way from cycle 30 or so. I'm now at 130 cycles.

 

[Krazy Bill]

You battery "clock" watchers need to just ignore whatever app of the day you're using to tell you about your hardware.

How much "real" time do you actually get from a charge? That's the clock you should be watching. I simply log the time I unplug and then look at the clock again when I get the "reserve" dialog screen. My usage never matches what the ever-changing calculations claim - sometimes better, other times worse.

 

[lebbeus]

You battery "clock" watchers need to just ignore whatever app of the day you're using to tell you about your hardware.

How much "real" time do you actually get from a charge? That's the clock you should be watching. I simply log the time I unplug and then look at the clock again when I get the "reserve" dialog screen. My usage never matches what the ever-changing calculations claim

Well Bill, no one is talking about the ‘clock’ which obviously constantly alters it's estimates depending on varying degrees of power comsumption. We’re talking about mAh in the physical battery which is much more accurate representation of how much power is available.

‘real’ time as you state really means nothing as usage is totally variable. I could cain the processor and maybe get 2-3 hours of use or be extremely conservative and get 9 hours.

 

[fskywalker]

How many hours of life are you folks getting from your 15 inch rMBP on web browsing and MS Office type applications?

 

[Schranke]

mine shows 98% right now. yesterday it were 103%, last week 95%.
since batteries are a bunch of chemicals it will be affected by temperature.