Too Slow and Doesn't Wake Up

It’s been a couple of years and I’m not a techie so bear with me. My battery was dying so I replaced the battery. I also ordered a SSD to replace my HD but I didn’t replace the SATA cables, and I expanded my RAM to 16 GB.

My system specs are:

• processor: 2.3 GHz Intel Core i7
• memory: 16 GB 1600 MHz DDR3
• graphics: Intel HD Graphics 4000 1536 MB
• Trim support = yes

Battery says:

•   Charge Information:
•   Charge Remaining (mAh): 3836
•   Fully Charged: No
•   Charging: No
•   Full Charge Capacity (mAh): 5252
•   Health Information:
•   Cycle Count: 81
•   Condition: Service Battery
•   Battery Installed: Yes

AC Charger Information:

•   Connected: No (plugged in)
•   Charging: No  (battery icon shows it’s charging)

My battery has never said it was fully charged even when it showed 100%. I followed the video tutorials on how to install a battery and condition it and how to install an SSD and boot up with a bootable USB. The videos also showed how screaming fast their “new" mid-2012s were with a timer. I didn’t get to enjoy any of this. I was wondering if I needed to replace the SATA cables.

Also, I had made the mistake of installing the 64-bit OS, then realized nothing worked with it and my Excel spreadsheets were literally backwards. I then erased everything again, re-initialized (again following a tutorial) and loaded Mountain Lion OS and upgraded to Mojave, which is where I’m staying put.

So these are my problems.  My Mac is very slow and won’t hold a charge for very long even with the “new" battery.  My last battery lasted 9 years.  When it’s charged up, I take it off of the charger, use it then close it.  When I go back to use it, I have to reboot sometimes several times a day with it plugged in and the battery is at 95%.  Sometimes it’s reliable.  Right now it’s being a pain.  I’m not sure if this is a hardware issue, or if I have legacy files from the 64 bit system when I restored my files and need the “genius” bar.  I did see another question regarding the same battery issues I’m having and the responder suggested the coconut battery app.   I can’t get it to download and half the time I can’t get access to the App store.

@bmx2019 I believe the fan is running because my laptop is always in my lap and it doesn’t get overly hot.

@dan I tried holding down the D at restart and received an error message about a missing file. I also tried option D at restart and recieved the same error message ‘Cannot load EFI/Drivers/Test/Support.efi. I read through Apple Support looking to see if the .diagnostics folder was in the right place but wasn’t able to find it.

EDIT: According to the Apple Forums it appears the Boot ROM was changed when upgrading to Mojave and option D is no longer available. Downgrading does not change the firmware.

@gizmowizards I did adjust the SMC following online instructions. I've been poking at this problem for over a year now. I haven't adjusted the energy saver settings. On battery and power adapter they’re set at 15 minutes.

I can’t seem to upload my screenshots using the media manager. I add my screenshots, press “Upload Media” it takes me to a new screen. The new screen has a “Back” button and an area to upload media or a URL. When I drag and drop my screenshots into that screen it takes me back to my original screen and the circle continues. What am I doing wrong?

@danj The only way I could load the images was to use a PC (smh). The battery was purchased 7/19, probably installed 8/19: