New battery dies on refurbished MacBook Pro Mid2015

"Official" Apple batteries are only available by having Apple install it or having an Apple Authorized Service Provider do it. Once they went to built-in notebook batteries, Apple stopped selling batteries as service parts to anyone else.

Apple has batteries made for them by trusted vendors. We may get a clue from "Power" detail in System Information. Do "About the Mac and click on the "System Report..." button. Once that launches SysInfo, select "Power" from the left-hand Contents pane to get this:

First look at the serial number. Although not definitive, there was one large batch of counterfeit batteries that all had the same bogus number—0123456789ABC. When I worked in law enforcement, we called that a clue!

Next, what Manufacturer code is shown: DP and SMP are the most common.

Now note the info around which I drew the red box. Copy and paste that here. That section shows performance numbers.

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Most likely they are installing a third party battery. The quality of third party Lithium-ion batteries is extremely poor even when purchased from a respectable vendor. You should avoid third party Lithium-ion batteries at all costs as long as an official Apple battery is available from Apple. If a third party battery is the only choice, then I would only purchase the battery from OWC (but even batteries from OWC can fail prematurely).

You should avoid this reseller since the quality of the batteries they are installing are horrendous.

In my opinion a battery whose health falls from 100 to 82 in 5 days with 8 cycles is not fit for purpose. If the seller cannot remedy, then I recommend you get your money refunded for the computer and shop elsewhere.

I found nothing out of order in the SysInfo data.

Thank you. As for software, a runaway process problem comes to mind but then goes away. That would cause a rapid charge level drain but should not decrease the charge capacity.

A bad charger shorting across the contacts maybe, but I feel that is not a likely cause. You can certainly check the Magsafe connector on both the computer and charger to look for dirty or stuck pins,

If it is a hardware fault in the computer and not the battery, is the seller going to stand behind it?

Walther Schoonenberg wrote:

I have a strange and very disturbing problem. I bought a refurbished MacBook Pro 15inch Mid2015. The computer looked as new and there was a brand new battery in it. But as soon I started using the machine the battery health dropped from 102 % to below 65% or so and the computer asked for replacing the battery. The firm from which I bought the machine replaced the battery with a new one, but for the second time the battery died within a few days of normal use. I returned again to the supplier that gave me another MacBook Pro of the exact same model, with almost the same serial number and again with a brand new battery. But today I noticed that the same problem is occuring again! I'm going mad! How is this possible? Can anyone explain this? What is going on here? The machine has all the recent updates for the Catalina macOS and I'm doing nothing strange with the computer, completely normal usage. I have another but old MacBook Pro in use running under El Capitan that has no problem like this and a battery health of 100 % (on this machine I typed this post) and the charging block was also replaced by my supplier (so that cannot be the problem).

And who is this mystery "replaced by my supplier" out of curiosity (?)