A method of arranging a plurality of internal components within a battery pack housing (100, 200), comprising the steps of: providing a pair of end caps, each end cap having a plurality of spaced apart recesses formed on an inner surface thereof which are shaped to receive a plurality of cell straps (410, 710) and a pair of power terminal leads, placing the cell straps (410, 170) and leads within the spaced apart recesses; disposing a plurality of cylindrical battery cells between the end caps so that ends of corresponding cells contact a given cell strap (410, 710) or lead; characterized in that: each of the end caps is provided with a plurality of spaced apart access holes which extend through a given recess, wherein the cell straps (410, 170) and leads are placed within the spaced apart recesses so that a portion of the cell strap (410, 710) or power lead is exposed through a corresponding access hole; wherein the plurality of cylindrical battery cells are disposed between the end caps so that ends of corresponding cells contact a given cell strap (410, 710) or lead at a junction that is exposed through a corresponding access hole, wherein sides of the end caps have a scalloped shape that conforms to the rounded shape of the cylindrical cells to constrain the cells there between; wherein the method further comprises the steps of; welding the cells straps (410, 710) and power leads to the cells through the access holes ( to form a core pack comprised of the cells connected to the straps (410, 710) and leads between the end caps, attaching a plurality of sense wires within outer surfaces of the end caps the core pack, wherein one end of each sense wire is a spring end which is retained within a corresponding access hole of the core pack to contact a junction of a cell strap/battery cell, and the other end of each sense wire is attached to a integrated connector formed in each end cap of the core pack, and inserting the core pack into the housing (100, 200). providing a pair of end caps, each end cap having a plurality of spaced apart recesses formed on an inner surface thereof which are shaped to receive a plurality of cell straps (410, 710) and a pair of power terminal leads, placing the cell straps (410, 170) and leads within the spaced apart recesses; disposing a plurality of cylindrical battery cells between the end caps so that ends of corresponding cells contact a given cell strap (410, 710) or lead; each of the end caps is provided with a plurality of spaced apart access holes which extend through a given recess, wherein the cell straps (410, 170) and leads are placed within the spaced apart recesses so that a portion of the cell strap (410, 710) or power lead is exposed through a corresponding access hole; wherein the plurality of cylindrical battery cells are disposed between the end caps so that ends of corresponding cells contact a given cell strap (410, 710) or lead at a junction that is exposed through a corresponding access hole, wherein sides of the end caps have a scalloped shape that conforms to the rounded shape of the cylindrical cells to constrain the cells there between; wherein the method further comprises the steps of; welding the cells straps (410, 710) and power leads to the cells through the access holes ( to form a core pack comprised of the cells connected to the straps (410, 710) and leads between the end caps, attaching a plurality of sense wires within outer surfaces of the end caps the core pack, wherein one end of each sense wire is a spring end which is retained within a corresponding access hole of the core pack to contact a junction of a cell strap/battery cell, and the other end of each sense wire is attached to a integrated connector formed in each end cap of the core pack, and inserting the core pack into the housing (100, 200).