I opened up my case and intended to replace the battery with one of the suggestions I've found here, but upon inspecting my cables directly connected to the battery I found one was not fully inside the plastic adapter that locks into the tablet's male connection. I reinserted it fully and reconnected the battery to the tablet, put it on the charger, and it's been two full days without any issues. No extreme battery level fluctuations, sudden power downs, green lines, or black screens. I ordered the second battery just in case, but it looks like it won't be necessary for some time.