Battery Dies While Partially Charged, Even after Resetting SMC and NVRAM and Clean Reinstall: Mojave

Hi everyone,

I've lurked on the discussion boards and looked everywhere here and on YouTube for a fix to this but nothing is working. Hopefully one of you all can help out.

I've got a mid-2014 MacBook Pro running the latest version of Mojave. From around the time I installed Mojave (early December?), I started having inexplicable crashes when running on battery power. I'm pretty deliberate about knowing how much juice the battery has, so this was really weird. The issue keeps happing when the battery is somewhere between 35 and 65% according to the menu bar monitor.

Before you ask:

1) Yes, I checked on the battery. It is "Normal" and the battery should still have about 300 charge cycles.

2) Yes, I reset SMC repeatedly.

3) Yes, I reset NVRAM repeatedly.

4) Yes, I disabled unnecessary iCloud functions, including Photos and FindMyMac, to reduce background energy drain.

5) Yes, I did a complete wipe and reinstall. Twice. It sucked.

6) No, I'm not using USB peripherals. I do have Bluetooth peripherals, but the problem occurs even when I'm not using them.

7) Yes, I've tried booting in SafeMode, but I couldn't figure out what made the problem happen that way. That's partially because the crashes are intermittent enough that they are hard to pinpoint.

I'm at a loss, but my computer is now basically a brick-in-waiting if I don't have it plugged in all the time. There is no rhyme or reason to the crashes as far as I can tell. I regularly have several apps running at once, but nothing that my computer shouldn't have the memory to handle.

Can anyone help? TIA