That won't help. The UMC that comes with the car has a small 'tail' that contains the 10A plug and some coding to tell the charger that it's a 10A plug. Tesla haven't told us when the 15A version will be available, but it'll be a tail to plug into the UMC. On a brighter note, a 10A plug will fit into a 15A socket and should work. If you want to spend the money, you can get an after-market portable charger that will go as high as 32A 3 phase.