MacBook Pro battery capacity dropped; replace it?

Is this the original battery? If so, 70 cycles sounds very wrong. If you click the "Battery Info" button in Coconut Battery, what does it show?

All aftermarket batteries are rubbish, and home battery replacement attempts have caused more "dead Mac" reports here than I care to count. The battery is GLUED in place. Invariably the nasty solvents required to loosen the glue gets in other computer parts and gives them the tech version of a smackdown. Dead Mac.

Unfortunately, Apple no long offers factory battery service on 2015 Macs so you are in a bind:

— do nothing except use the computer on wall power with the charger.

— pay a lot of money or a sub-standard battery that may, in the worst case, kill your computer

— Buy a new computer.

I love keeping old Macs in service but, give the above issues, I cannot see throwing money at a computer that cannot be upgrade past macOS 12 "Monterey."

Batteries are a wear item, like the soles of your shoes and the tires on your car. Their expected lifetime depends on use (as reflected in Charge cycles) and also in the passage of time, used or not. After a while, you should expect to have to replace the battery. 

Battery life  also depends on two factors you may be able to control a bit better. Lithium polymer batteries deteriorate when they get too hot, and when they are subject to very deep discharge. These should be avoided when possible.

Despite using these batteries in millions of Apple devices, there is still a lot of of randomness in exactly which battery will fail when.

Apple uses the criterion that a battery that doesn't consistently hold 80 percent of its original charge capacity should be serviced, and likely replaced.

Unfortunately, Apple no longer offers battery service for MacBook Pro models as old as your 2015 model.

ZensUnstable wrote:

Hello, i have got a macbook pro 2015 13inch, and when i opened coconutbattery, It says 75% remaining of capacity. but some 5-4 days later, it suddenly Reduced to whoppin 66%. i dont know what is the cause of this,

Such drastic changes indicates the battery is failing. While Apple batteries always have some minor fluctuations up & down all the time, the large jumps indicate a hardware failure with the battery.

i tried to look for batteries online (e.g like Shopee), it was expensive. should i replace the battery of my macbook or just keep using it?

FYI, the quality of third party Lithium batteries is extremely poor even when purchased from respected vendors such as OWC (has regional authorized local retailers) and iFixIt. I personally would not trust any other third party sources.

Now, replacing the battery yourself is a very difficult process (I have done this with multiple models). I have seen multiple people post on this forum about having laptop issues after performing their own battery replacement .....they usually accidentally damaged the laptop's Logic Board during the repair (other times damaging the Trackpad & Trackpad cable). OWC does provide a video, but the video looks easier than it really is and OWC even recommends having a professional perform the replacement.

"MacBook Pro battery capacity dropped; replace it?: Hello, i have got a macbook pro 2015 13inch, and when i opened coconutbattery, It says 75% remaining of capacity. but some 5-4 days later, it suddenly Reduced to whoppin 66%. i dont know what is the cause of this, i just used it for some light gaming, light game engine works, and some music production in REAPER. i got surprised when i saw it was on 66%. and i tried to look for batteries online (e.g like Shopee), it was expensive. should i replace the battery of my macbook or just keep using it?"

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Thank you for the screenshot.

VERIFYING THE BATTERY HEALTH ON A MAC:

You are using a Third-Party app here; it is not build into the macOS' encoding. So, rely on your Mac to investigate and view the Battery Health drop, as it is more trustworthy. As for the reason of dropping, it is no possible to know why, nor when, the Battery Health decreased. In fact, it can even increase in percentage.

1. Click: Apple menu
2. Select: System Settings...
3. Click: Battery
4. Click: the encircled "i" on the far-right of Battery Health
5. View: the Percentage of the Maximum Capacity.

Your Mac's Age is More than a Decade Olde:

You'd Mac is extremely obsolete, and is incompatible for more-recent macOS versions. So, consider upgrading, if not done so, already. Apple has a reputation for providing macOS update for their device fore 7 years, and then stops doing so. I'll keep my 2018 Mac, as it has an Intel Processor, for troubleshooting purposes, and ease of Virtual Machine use.

FWIW, I would not spend any money trying to repair an obsolete/vintage computer. This includes changing out the battery.

TheLittles wrote:

VERIFYING THE BATTERY HEALTH ON A MAC:

You are using a Third-Party app here; it is not build into the macOS' encoding.

FYI, from what I've seen, Coconut Battery has always appeared to show accurate battery information. I've compared its information to the battery details that can be retrieved from built-in macOS command line utilities.

I mainly use Coconut Battery to keep a battery history of my laptop & my iPhone, and to confirm my custom battery test scripts are still pulling correct details. Plus I use it to assist other users on the forums. Unfortunately macOS does not provide the same level of battery information in an easy to use GUI app.