I have a 2017 MacBook Pro 15 with a fairly new battery. One day it just suddenly switched off with 80% battery remaining and when I switched it on (or tried to) it said the battery was empty.

Since then the MacBook switches off randomly while reporting a full state of charge and when I do plug it in to charge it, it charges from 0% to 5% - 15% then it jumps to 100% all in about less than 15 minutes.

I found this command ioreg -l -w0 | grep Capacity and it showed me something interesting. Apparently, the battery is made up of three cells each at about 4.35V when fully charged... the peculiar thing is that the reported voltages of one cell differs from the rest. eg... (4216mV, 3521mV, 4210mV). The MacBook usually switches off when the faulty cell has less than 2800mV. (When on low power mode and screen brightness at minimum)

So I figured the reason my MacBook swithes off while it reports > 80% battery is because one of the cells is way more depleted than the rest, then when the battery voltage drops below the minimum (I think around 11.2V) to run to electronics then it switches of

here's a sample output of ioreg -l -w0 | grep Capacity

└─[$] ioreg -l -w0 | grep Capacity                                                                                                                                                                                                                                 [17:18:58]
| |           "AppleRawCurrentCapacity" = 6971
| |           "AppleRawMaxCapacity" = 7128
| |           "MaxCapacity" = 7128
| |           "CurrentCapacity" = 6971
| |           "LegacyBatteryInfo" = {"Amperage"=18446744073709550486,"Flags"=4,"Capacity"=7128,"Current"=6971,"Voltage"=11713,"Cycle Count"=12}
| |           "BatteryData" = {"LifetimeData"={"TotalOperatingTime"=28160,"UpdateTime"=1655739345,"AverageTemperature"=273,"Raw"=<0000000000483ff4000108f100000000060ae9c40080e467b24000000000000001d9004e1106084b33091fc6155be5271a8ce074eadce8ac01110006e0070031>,"TimeAtHighSoc"=<00000000230500001200000000000000>},"Serial"="C01514309YEF90MA4","ChemID"=3165,"Flags"=192,"DataFlashWriteCount"=0,"PassedCharge"=18446744073709550538,"Voltage"=11798,"ResScale"=167,"RaTableRaw"=(<0000000000000000000000000000000000000000000000000000000000000000>,<0000000000000000000000000000000000000000000000000000000000000000>,<0000000000000000000000000000000000000000000000000000000000000000>),"StateOfCharge"=98,"Qmax"=(6580,6600,6590),"CycleCount"=12,"DesignCapacity"=6600,"SystemPower"=1497,"AdapterPower"=0,"PMUConfigured"=192,"DOD0"=(9280,9344,9248),"PresentDOD"=(40,41,40),"CellVoltage"=(4214,3276,4223)}

As you can see the battery is quite new (cycle count = 12) and the faulty cell, "CellVoltage"=(4214,3276,4223)

Can any please help me fix this issue? The battery lasted about 6 hours with moderately heavy use which was perfect for me to outside to the park or a coffe shop and code there instead of being stuck in the four walls named my bedroom.

I think I need to find a way too either charge only the depleted cell or to discharge the full cells. I'm hoping to get a software solution as first preference, or I can right my own code to manage the charging if software like that doesn't exist and my last option is to open up the MacBook and manually discharge the other two cells which I don't think is a good idea... Or maybe I have made the wrong diagnosis and there's a different solution to my problem.

I have tried reset ing the SMB and NVRAM with no luck.