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How does Coconut determine battery health percentage? My new rMB, built in 10/26/2015, now with 3 cycles on the battery, went from 99.6% health yesterday to 98.2% today.

Hey, it went from 98.2 to 98.4 to 98.5 as I'm typing this o_O
 
How does Coconut determine battery health percentage? My new rMB, built in 10/26/2015, now with 3 cycles on the battery, went from 99.6% health yesterday to 98.2% today.

Hey, it went from 98.2 to 98.4 to 98.5 as I'm typing this o_O
Are you talking about the Design Capacity % shown in the bottom green bar? That comes from the maximum charge divide by h design capacity. So for example if you had a maximum charge of 6000 and a design capacity of 6300 that would be a 95% "health" (6000/6300=.95).

It is normal for that to fluctuate around a little even when new.
 
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Are you talking about the Design Capacity % shown in the bottom green bar? That comes from the maximum charge divide by h design capacity. So for example if you had a maximum charge of 6000 and a design capacity of 6300 that would be a 95% "health" (6000/6300=.95).

It is normal for that to fluctuate around a little even when new.
Yes, and thanks for the explanation how Coconut makes that calculation.

coconut.jpg
 
There's no way this can be right...right? From the 2nd to 3rd charge it went down to 94%?

That's 1 day!
 

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There's no way this can be right...right? From the 2nd to 3rd charge it went down to 94%?

That's 1 day!

I returned my Macbook for this exact issue. No matter which ones, at the store or continuous returns and repurchases, this issue is persistent
 
if your mac is underload and warmer the battery health will de down by a few percent
if you let to charge it and cool down the battery health percent will rise
Tested on 2x 12" Macbook and 1 15" Macbook Pro
 
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I returned my Macbook for this exact issue. No matter which ones, at the store or continuous returns and repurchases, this issue is persistent
That sucks. Well I'm within the return period but I saved over $400 at Best Buy with sales and movers coupons...so did you have to return within the 30 day period? Or did they do it after your 3rd issue for the Lemon policy?
 
That sucks. Well I'm within the return period but I saved over $400 at Best Buy with sales and movers coupons...so did you have to return within the 30 day period? Or did they do it after your 3rd issue for the Lemon policy?

I returned 3 computers within the 14 day policy over the summer. So I played around with it for 1.5 months and then i gave up. Apple said it could have been a bad batch, but I think otherwise. I LOVE LOVE LOVE this computer, but I will now wait till 2.0.
 
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I returned 3 computers within the 14 day policy over the summer. So I played around with it for 1.5 months and then i gave up. Apple said it could have been a bad batch, but I think otherwise. I LOVE LOVE LOVE this computer, but I will now wait till 2.0.
It can be that the "Design Capacity" value is just set too high, and that what is now shown as 85-90% is actually the normal capacity which gives you the 9 hours Internet surfing battery usage time. I'd like to know if these laptops become "stable" at 85% or that they drop further and further, which is NOT normal and indeed warrants a return / replacement.
 
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It can be that the "Design Capacity" value is just set too high, and that what is now shown as 85-90% is actually the normal capacity which gives you the 9 hours Internet surfing battery usage time. I'd like to know if these laptops become "stable" at 85% or that they drop further and further, which is NOT normal and indeed warrants a return / replacement.
gives me more like 6-7 hours of internet surfing time. which minimal brightness and very low cpu speed
 
On my new Retina MacBook iStat is telling me 244 cycles (six months) and 82% battery capacity. I get about 4-5 hours web surfing out of it. I see warranty service in my future.
 
I returned 3 computers within the 14 day policy over the summer. So I played around with it for 1.5 months and then i gave up. Apple said it could have been a bad batch, but I think otherwise. I LOVE LOVE LOVE this computer, but I will now wait till 2.0.
Did you really test all three over time to see if it were accurate with the performance? Doesn't sound too good.
 
Sometimes mine shows 82 percent and sometimes 87 percent lol. Its 2.5 year old now

If it's like mine it'll stay just over 80% (mine was at 82%) till the 3 year mark so that Apple won't do **** for you (even with extended AppleCare). Then it'll drop quickly. Went from 82% to 72% in 6mo (under 700 cycles).
 
Just got my gold MacBook 2 weeks ago. Only 6 cycles so far (I think 3 were out-of-box) and reporting 99% battery life. We'll see how it goes over time.
 

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Just got my gold MacBook 2 weeks ago. Only 6 cycles so far (I think 3 were out-of-box) and reporting 99% battery life. We'll see how it goes over time.

My guess is that age of the battery is a huge factor too. My MBr was only used for 20 days today and only at 7 load cycles now... I'm at 96.1% already but my computer is nearly 6 months old based an manufacture date and the battery is even older. About 7 months.
 
What's you all's battery manufacturer?

My vendor is 'SMP' and now only 87.6% with 52 cycles. :(
 
I took my Macbook in to my local Apple reseller as I've been having problems with battery life on a fresh install of El Capitan, getting approx 4 hours. It was only charging to 70-80% (4500-4600mAh) according to the battery app I installed from App Store. They've used Apple Diagnostics and found it charges to 90% supposedly. Could there be any reason for the difference in reported capacity? This is a nightmare for me as I need the machine for work and the battery life is dire. Apple won't fix it with their diagnostic readout.
 
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