Chosen Solution
I replaced the battery in my laptop by following a YouTube tutorial and everything was fine for 24 hours. I could see the cycle count reset to 1 after a full charge, but now the battery isn’t even recognized in system information and the laptop will not work without being connected to the power adapter. I found this out by opening the laptop expecting the screen to immediately light up and after pressing the power button a few times and hearing the chimes for only the first few presses, I plugged it in. So basically, what did I mess up? Considering it worked for 24 hours I’m at a loss. I was trying to not have to dish out $1500 and rather just the $120 for the battery but will I now be out the sum of both? Update (05/10/2022)
@danj Also, in doing this, I realized how laggy and slow my laptop now is, if that helps!
OK thats very helpful! So we can tell SMC is working, but it’s not getting any data from the battery! This is a bad battery, the micro controller within it has failed. Because SMC has lost access to the thermal sensors within the battery, SMC is in CPU safe mode which is where the SMC lowers the CPU’s clocking and ramps up the fans RPM to prevent the CPU from getting overheated. I would talk to the battery seller to get a new battery and/or get your money back to then get a replacement from another source. The Unibody A1278 battery is getting hard to find new (fresh) so be careful as there are a few sellers who glop two older batteries together to make a good working one.
That appears to be a 2008 13" Core 2 Duo. Entirely possible that something else has failed, unrelated to the battery. Or, perhaps you got a bad battery (which is a strong possibility from what you say). Suggest putting the old battery back in to see if it is recognized in System Profile.
