Chosen Solution
I personally don’t recommend APFS on SATA based systems as it’s not designed for the SATA interface, its ideal for PCIe with either AHCI to NVMe based drives (blade SSD’s). I would revert the drive to HFS+ (you’ll need to reformat the drive using Sierra) Going to a SSD drive over a HDD was a good move as a HDD consumes more power. jumping from 4MB to 16MB RAM will use more power, but the generation of SO-DIMM chips will have a bigger bearing then the size per-say. Count the chips on the SO-DIMM the fewer the less power they need. OK, so were does that leave us? More likely your battery needs to be replaced given the systems age. Let’s get a better view of things, install this gem of an app! CoconutBattery take a snapshot of the apps main window and post it here for us to see Adding images to an existing question I would adjust your systems energy settings to maximize your systems run time. If you really need more run time beyond that you should consider reducing the number of open apps and/or tabs you have in Chrome.
