I began having issues almost a year ago with the charger adapter (cigarette lighter) in my 2011 Countryman base model. The MINI dealer was very kind in swapping out the fuse for me at a nominal cost and advised me not to use the dual USB charger or anything that would potentially pull too much juice for the adapter to withstand. Well that fuse didn't last but maybe one or two months and since then I've had fuses replaced a total of three times. Fast forward to May 2016 and the dealer suggested replacement of the entire part to try and resolve any issues that were causing the blown fuses. The new adapter lasted a total of three weeks and I've been without a legit place to charge my phone since then.
Needless to say, I'm pretty frustrated that this keeps occurring because of scheduling time out of work and being forced to use the USB port behind the shifter to merely keep my charge from going down as I listen to music or use Waze.

Anyone have any idea what may be causing the issue or solutions to have it resolved once and for all?

 

What brand is your phone charger? I have experienced blown fuses using a cheapy charger, but when using an authentic iPhone or Samsung charger no issues.

 

Agree with charger being the issue, one other thing you could try is another outlet if you have them in the car. Mine has three outlets. Cheap charger might have contacts internally too close causing short or sparking.

 

It's not the dual USB charger....at the high end a 3 port USB charger is maybe 4 amps...
The port has a 15 amp fuse....

 

A common know issue with any car that has a key on socket is that users leave the device attached to the cable and plugged in. Although as stated earlier charging is only a few amps at best BUT upon key on there is a spike as the phone is either powering on or changing to charge mode. This spike may be your issue.

Changing the socket may help as over the years corrosion and wear increase amp draw. You may want WITH KEY OFF and a plastic tool pry the ground tabs closer to the center. This increases the tension on the charger reducing amperage draw at key on.

Hope this helps.