15" MBP Mid 2014 repeat rebooting on power after battery change

[peadarm]

For a few years the battery on my MacBook Pro 11,2 (Retina, 15-inch, Mid 2014, model number A1398, OS Catalina 10.15.7) showed as 100% full and needing a service - but it wouldn't run at all without a power connection. The battery wasn't at all bloated. I recently replaced the battery - the new one has a larger capacity, there are no error messages, and the MBP now runs without mains power. With two major problems:

1. It won't run on the mains/grid now without rebooting after a few minutes. I've used two different chargers. If I start it up connected to power then disconnect it, rather than switch over to battery power the screen just goes blank.

2. When the battery gets down to around 60% it suddenly jumps to 2%. This is not the true state of the battery, as it will carry on running for hours. However, if it goes to sleep then it can't be woken or restarted on battery power as the system thinks the battery has run down. I haven't been able to do any full charge-discharge cycles for this reason.

I did perform several SMC resets, but couldn't do a PRAM reset: the R key on my built in keyboard no longer works (!), and the external keyboards I normally use almost certainly aren't recognised early enough. I've tried to swap the R and Z keys (using Karabiner 10:10) - unsuccessfully, but as with the external keyboards I'm not even sure the key swap would take effect on time anyway. Plus I don't know a successful PRAM reset would be my silver bullet (time/date is fine, problem more likely to be sorted by SMC reset - which I've done?)

As the MacBook seemed to be running fine on the new battery when I tested it, I went ahead and glued it in. The same battery (Manufacturer: Dongguan BND Electronics) also appears to work fine for other buyers on Amazon. Any ideas for fixing this? Or should i give up on my new battery, disconnect it and go back to using the MacBook permanently connected to AC power (assuming that will still work)?

 

[Bigwaff]

I assume you calibrated the battery after install. If so, seems like a bad battery to me. Return it for another.

 

[peadarm]

No I didn't calibrate it properly because I took the message that the power was running low at face value and plugged it in to recharge. I subsequently realised that it was nowhere near zero.

The battery in itself seems to work ok.

 

[Audit13]

Does the onboard Apple diagnostics report any issues?

Coconut battery report any issues?

 

[peadarm]

No issues found by either Diagnostics or Coconut.

 

[DeltaMac]

I think it is worth your time to try a complete battery calibration. Follow the steps, as listed. Don't try to over-think what you might see, and try not to make assumptions, until after completing that full charge, then allow to rest fully charged, then use your MBPro to discharge until your MBPro goes to sleep (fully discharged), then leave your MBPro to rest for at least 5 hours, THEN plug back in to recharge fully. (follow the steps, all are listed on that page twice...)

Calibration (as presented by iFixit.com) if you need it:

Battery Calibration

All newly-installed smart batteries should be calibrated as soon as possible. This helps your phone or laptop get an accurate reading on the battery’s state of charge.

www.ifixit.com

Main steps are near the top of the page, with same basic steps listed further down the page, with a bit more detail.
Do the steps, even if your think it won't work, or think you have already done the same steps. Repeating the calibration steps won't hurt anything, and might just get your battery on proper "speaking terms" with the logic board, which is the primary plan for the calibration.
After trying all the calibration steps, the battery is still the same, send it back for replacement (third-party batteries can often be a crap-shoot, regardless of the reports and opinions that you might see. I have needed replacements for new batteries a couple of times (I work with a local PC shop, doing what I can to repair the occasional Mac, which commonly can be failed batteries. Last couple of years, I have replaced about 20 batteries, with 2 replacements failing almost immediately. The reseller swapped the bad ones, and the replacements worked fine.

 

[f54da]

Your battery is bad. Doesn't matter that it's a "new battery", there is no such things as reliable aftermarket battery for mac. They all use second-rate, possibly recycled cells.

Edit: Missed that you didn't try calibrating the gas gauge first, since you mentioned it carries on at 2% for several hours, calibrating might help.

 

[peadarm]

I've done the calibration a couple of times now - I didn't manage this initially because it shuts down when connected to the power, but have since been able to use Recovery mode for that stage.

It continues to shut down or reboot when connected, but works fine and for hours on the battery when it is fully charged.

Edit: given that the new battery 'works' (and that the old one registered as 100% charged but didn't work), I'm inclined to believe the fault probably doesn't lie with the new battery??

 

[Bigwaff]

given that the new battery 'works' (and that the old one registered as 100% charged but didn't work), I'm inclined to believe the fault probably doesn't lie with the new battery??

You can believe. However, unless the battery brand is complete garbage, it is unlikely a third battery will exhibit the same inconsistent charge level stats. I’m inclined to believe your new battery is bad. But first, deal with that keyboard issue. You can reset PRAM from command line in Terminal with “sudo nvram -c” then shutdown and then boot.

 

[peadarm]

Thanks. I did do the sudo nvram -c command plus boot.
In retrospect I would've left the battery unglued for longer....