My MBP will only charge with a T shaped magsafe now I have a MacBook Pro (15-inch, Early 2011) which came with a L shaped magsafe charger. I have been having problems for sometime now, wouldn't charge properly, cut off randomly, charger would cut out/not good connection. I replaced the battery, bought new chargers, reset the SMC and NVRAM many times. Eventually I gave up on it and let it sit for many months and used a work laptop.

A couple days ago I decided to see if it would start and of course the L shaped charger I bought from Apple wouldn't work, I then plugged in my wife's cheap Amazon T shaped replacement charger and it connected great and started charging perfectly. I have tested many perfectly good L shaped chargers since and they will not work well, keep cutting out. 

Any ideas? Is my port wearing out and that T shape just happens to fit better?
Technically speaking, you should be using the L-shaped adapter.

As to why it's working with the "incorrect" adapter and not the correct one is because the pins on the MagSafe connector are probably pushed "in" or just contaminated.  Additionally, the pins on the T connector stick out just a bit further than the L connector.

 

You may have some luck cleaning out the MagSafe connector, but in my experience, you have to replace it.

You have a few options:


use the adapter that's currently working
attempt to clean the MagSafe connector
replace the DC in board


Replacing the DC-in board is not "difficult" inasmuch as being tedious and detailed.   It involves removing the logic board because the connector is under it; iFixit has excellent step-by-step guide.

If this is not your cup of tea, I would simply continue using the adapter that works.