SMC reset to fix battery not working, but cant be sure SMC reset has taken place

I have had a new battery in my mid 2012 15" macbook pro running 10.11.6

The battery health as monitored through a battery health app downloaded from the mac app store has been deteriorating ever since i installed it and after about 3 months the battery is saying "Service Battery"

This doesn't tell the full picture though, as if it use my Mac once i get the "low battery 9 minutes remaining" warning, it will go on for hours without cutting out.

Ive been told i need to do an SMC reset to address the issue, but each time i do it following Apples guides for laptops with a removable battery, it dosnt fix anything?

How can I know that an SMC reset has taken place, can it be seen in the logs ? Or can i do an SMC reset through some kind of GUI tool which will give me feedback instead of the standard way which i cant be sure has worked.

Here is an output from About this mac > System Info > Power

Model Information:
  Serial Number:    REDACTED
  Manufacturer: SMP
  Device Name:  REDACTED
  Pack Lot Code:    0
  PCB Lot Code: 0
  Firmware Version: 2
  Hardware Revision:    00aa
  Cell Revision:    2
  Charge Information:
  Charge Remaining (mAh):   220
  Fully Charged:    No
  Charging: No
  Full Charge Capacity (mAh):   3918
  Health Information:
  Cycle Count:  81
  Condition:    Service Battery
  Battery Installed:    Yes
  Amperage (mA):    -1943
  Voltage (mV): 10877

System Power Settings:

  AC Power:
  System Sleep Timer (Minutes): 3
  Disk Sleep Timer (Minutes):   0
  Display Sleep Timer (Minutes):    3
  Wake on AC Change:    No
  Wake on Clamshell Open:   Yes
  Wake on LAN:  Yes
  AutoPowerOff Delay:   14400
  AutoPowerOff Enabled: 1
  Display Sleep Uses Dim:   Yes
  GPUSwitch:    2
  Hibernate Mode:   3
  PrioritizeNetworkReachabilityOverSleep:   0
  Standby Delay:    4200
  Standby Enabled:  0
  Battery Power:
  System Sleep Timer (Minutes): 10
  Disk Sleep Timer (Minutes):   0
  Display Sleep Timer (Minutes):    2
  Wake on AC Change:    No
  Wake on Clamshell Open:   Yes
  AutoPowerOff Delay:   14400
  AutoPowerOff Enabled: 1
  Current Power Source: Yes
  Display Sleep Uses Dim:   Yes
  GPUSwitch:    2
  Hibernate Mode:   3
  Reduce Brightness:    Yes
  Standby Delay:    4200
  Standby Enabled:  0

Here is an output from the command system_profiler SPPowerDataType | grep -i "charge information" -A 10

Charge Information:
          Charge Remaining (mAh): 234
          Fully Charged: No
          Charging: No
          Full Charge Capacity (mAh): 3918
      Health Information:
          Cycle Count: 81
          Condition: Service Battery
      Battery Installed: Yes
      Amperage (mA): -2579
      Voltage (mV): 10890

It's quite possible you have a defective battery, bad cable or power handling chip issue on the logic board itself. From the output you posted, here's what we know.

• 81 cycles and FCC of 3918 mAh is way out of specification
• The Voltage and charge measurement that you have 234 mAh (mili-amp hours) remaining
• It's showing a draw of approximately 2.5A (battery is being drained)

The SMC can only accumulate how much battery capacity is left by measuring the current power against the current draw and known full capacity. In this case, it's measuring that you're out of power and indicating your battery needs to be serviced.

There's no "dipstick" that can give you the actual charge, the SMC must calculate it and from the data it's getting from the battery, it thinks it's failing even though it continues to work.

Your best bet is to replace the battery (it's probably still under warranty) and still more likely to be the cause if you were careful with the cables and reseated them.