How do I charge a Magsafe/Magsafe 2 MacBook?

In order to charge the Magsafe or Magsafe 2 MacBook, you need to get an adapter.

There are USB-C to Magsafe/Magsafe 2 adapters available, like the one below from eBay:

https://www.ebay.com/i/253856178873?rt=nc&var=553149330240&_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D2%26asc%3D20160908110712%26meid%3D4f8ab85d95fd4445a3d2c04f4525511d%26pid%3D100677%26rk%3D10%26rkt%3D30%26mehot%3Dlo%26sd%3D132697702010%26itm%3D553149330240

If you have a MacBook Pro 15"/17", please choose the 85W power version. For the MacBook Air or MacBook Pro 13", select the 60W power version.

In the picture, the HyperJuice battery is connected with the USB-C to Magsafe 85W adapter on the MBP 15" Retina 2012.