This battery sled along with my NLPWM bezel (can be found in my store) will allow you to fit 3x 18650s in an Alpinetech B Box with a NLPWM board.
You will need 3 of each of these contacts:
1)
http://www.mouser.com/Search/ProductDetail.aspx?R=228virtualkey53400000virtualkey534-228
2)
http://www.mouser.com/Search/ProductDetail.aspx?R=209virtualkey53400000virtualkey534-209
Tips,
1) You will have to cut the diplay leeds on the back of the board with flush cutters.
2) The fit is tight so ensure to keep even pressure on the sled to ensure it lays completely flat on the enclosure when adhearing in place.
3) Not all 18650s are created equal all have fit for me (he4, efest 35a, sony, blue 25r) except for the new green 25r batteries which are slighly thicker than most and cause a slight gap with the lid. Not noticible but it there.
4) You may need to slightly sand the side of the sled if it is too tight. do this on the side that will face your NLPWM board.
Again this is a tight fit but if done corectly it works great.