Slow charging and sudden battery life loss
After putting off the upgrade for about a year and a half, I finally swapped out the battery in my early 2011 MBP with new stock from iFixit. The initial result was good: 6,058mAh through the first 3 cycles, per Coconut Battery. I did notice that it was taking longer to charge the computer, but I attributed that to the new battery's size - I was working with 3,528mAh (61% of original capacity) on 1,616 cycles before this new battery.
Couple days later, and I noticed two things. One, my battery capacity has already dropped off to 5,252mAh (91% of factory capacity) after 5 cycles. Two, my computer had charged maybe 20% over the course of 4 hours while on power adapter. Coconut Battery reported it was charging with about 3.66 watts. I have noticed this issue from time to time.
Do you guys think it's the new battery? The power adapter and cord? Or perhaps the MagSafe power port? My power adapter and cord is not as aged; I had to buy a replacement about 4 years ago. The MagSafe port is showing its age somewhat; it definitely doesn't look very clean. When I reset the connection, sometimes it'll jump to a higher wattage for charging (like around 12 watts). One last time I noticed recently was that the LED would slowly dim out once in a while - weird!
Answers greatly appreciated!!