Battery longevity - my battery is down to 15% capacity

[Poki]

Just curious - what is your experience with the longevity of the batteries Apple puts in MacBook Pros? I've got a 15" mid 2009 model, which was the first one with the non user serviceable battery, which Apple advertised as keeping 80% of its charge after 5 years of use.

As you can see, I didn't use it too much, and the capacity already dropped to 70% after just three years of use. Now it's down to 15%, or about 40 minutes of real world browsing use. I'm using this machine as a stationary browsing device mostly nowadays, so it doesn't really bother me, but did anyone experience better longevity? I'm a little worried since it's even harder to replace the batteries of the newer models -- how much does Apple currently charge for a battery replacement in a current 15" MBP?

 

[New_Mac_Smell]

I've always had good use for 4 years then they start to fade. They've always been far better quality than Windows devices I've used, that start to noticeably deteriorate after 6 months.

You can easily change the battery in that 2009 model for around $70, just make sure you get a credible brand. There's a lot of fake cheap stuff so use your judgment.

The newest ones are pretty much impossible to do yourself. But Apple charges can be found here https://support.apple.com/mac/repair/service.

Just a word of caution as I know you said the battery life didn't bother you. But take 5 minutes to take off the rear and check the condition of it, at 97 months old it's way past its expiration date, and those things can be seriously dangerous if in a bad condition. If in any doubt or if you can just take it to your nearest Apple shop and ask them to have a look, they won't charge you for that.

 

[Poki]

Thanks for the link and the tip! Actually, the price for a battery replacement seems pretty reasonable, so I'm not gonna worry about that.

I just took a look at my battery, and from the outside, it looks fine. The battery menu in macOS does say "Service Battery" for a few years now, but I guess that's just due to the low capacity. I hope it doesn't explode anytime soon, and if it dies at some point - well, 97 months is a good lifespan for any computer I'd think.

 

[ZapNZs]

While many things play into the longevity of lithium cells, IMO, the rapid drop in capacity (provided Coconut Battery's logging is accurate) is not normal, and to me this suggests that your battery may have had some type of heat damage, overcharging damage, damage from improper storage, or had not-so-great manufacturing tolerances that caused premature wear. I believe Apple rates their LiPo cells with 2009-2017 MBPs for maintaining 80% design capacity at 1,000 charge cycles (with a cycle being defined by Apple as IIRC a discharge or more than 20% total capacity - how a cycle is defined can vary by Maker.)

With the current version of AppleCare, I believe Apple replaces the battery free of charge as soon as it hits 80%, regardless of the cycle count. This change I believe was very recent.

I agree with New_Mac_Smell - might as well take your computer AND your charger to an Apple Authorized Service Provider and have them perform MRI. It will obviously say the battery is bad, but it will also test the charger and look for any other hardware problems. You have already visually checked the battery for any deformation, leakage, or swelling, which is always a good thing to periodically do (especially with batteries that have passed their end of usable service life.)

 

[magbarn]

Lithium ion batteries also don't like to sit at 100% all the time. They like to "exercise" and not 'sit on the couch' being plugged in all the time...

 

[carlob]

almost 4 years

 

[ZapNZs]

Lithium ion batteries also don't like to sit at 100% all the time. They like to "exercise" and not 'sit on the couch' being plugged in all the time...

As they like most to be at a state of about 3.7 volts, especially over prolonged periods of inactivity, at their full surge charge (ex: 4.20 volts), they are definitely being stressed. Deep discharges by far place the greatest stress/wear on lithium cells (short of overcharging and operating in extreme heat), and one single deep discharge may cause more wear than 5, 10, or 20+ more shallow discharges.

I am not sure what Apple's cutoff point is on their portables, but my guess is that it happens intentionally well below 4.20v to extend service life and reduce the amount of wear that continually sitting at 100% will cause. Where as my older Pila charger takes IMR/ICRs right up to the 4.205 voltage mark, some of the newer chargers I have (such as those from XTAR and NiteCore) terminate closer to 4.15 volts (and by doing so equates to slightly lower run time but a slightly longer service life.) I've always been curious of how Apple manages their charging specifications.

Ironically, sitting at 100% continually causes wear (how much depends on at what the Maker does in regards to their chosen termination current). Using the battery also causes wear (especially when running it down low.) Heat expedites wear. And with a laptop, all of these things are unavoidable. Laptops and lithium cells make one of the most unlikely couples in history lol

 

[pika2000]

Although modern batteries are not as finicky as older ones, I still find the having them connected to A/C 100% of the time can have some negative effects. This happened to my 2012 MacBook Air. It's the one hat I had connected pretty much 100% of its life, and its battery deteriorated worse than my other Macs (not as severe, but worse for its age and cycle). I finally bit the bullet and paid Apple for a newer battery as it was shutting down at ~30%.

 

[New_Mac_Smell]

There's a lot of hangups from older NiCad batteries with regards to memory and such that cause a lot of misconceptions not the internet. Modern LiIon batteries don't have those kinds of issues.

When your device (I don't know for other manufacturers but in 2017 I'd assume) is fully charged, it shuts off the charging circuit when the battery is full and runs straight from the source. It is absolutely fine to leave your device plugged in all the time and does no discernible harm to the device. The major affects are as always heat and constant extreme power drain/charge cycles (Going from 100%-0% every day). The other issue is if leaving the device for a period of time.

Apple's batteries are considered good for 1000 cycles, and if you drain it 50% and charge it to 100% twice this counts as a single cycle, not two.

So the best advice is to just use the device as you want and don't worry about it. If you travel a lot and run on the battery, it's fine. If you work in an office and have it plugged in all the time, it's fine. Nothing will be noticeable for four years in the average case, with serious degradation occurring after around 5-7 years. By which time most people will likely be upgrading.

 

[magbarn]

There's a lot of hangups from older NiCad batteries with regards to memory and such that cause a lot of misconceptions not the internet. Modern LiIon batteries don't have those kinds of issues.

When your device (I don't know for other manufacturers but in 2017 I'd assume) is fully charged, it shuts off the charging circuit when the battery is full and runs straight from the source. It is absolutely fine to leave your device plugged in all the time and does no discernible harm to the device. The major affects are as always heat and constant extreme power drain/charge cycles (Going from 100%-0% every day). The other issue is if leaving the device for a period of time.

Apple's batteries are considered good for 1000 cycles, and if you drain it 50% and charge it to 100% twice this counts as a single cycle, not two.

So the best advice is to just use the device as you want and don't worry about it. If you travel a lot and run on the battery, it's fine. If you work in an office and have it plugged in all the time, it's fine. Nothing will be noticeable for four years in the average case, with serious degradation occurring after around 5-7 years. By which time most people will likely be upgrading.

View attachment 702887

Lithium batteries don't like to be fully charged nor discharged for prolonged periods of time. In industrial applications most lion batteries are kept in the 20-80% charged states