Sunday, February 5, 2023

SMS Controller and Motor Terminal Blocks - 1

There are multiple possible cable lugs and terminal blocks to choose from.  In all cases the 2/0 multi-strand wire it is a challenge to slide into the fitting without bending back some of  the wires (DSC01512 below).

DSC01510 of the commercially available mechanical lugs purchased from Home Depot (two per pack at $3.75).  These lugs are 5/8" wide and 1.5" long and 13/16" tall and they have an opening for the 2/0 wire of  0.4435" (11.26 mm).  It takes patience to insert the 2/0 wire into the opening without bending back some of the wires. (see DSC01512).

The Aluminum set screws are 0.5950" long and rounded contact (convex), are 7/16"-20 thread,  use require a 3/16" hex key to tighten.  An alternative would be to use 18-8 Stainless Steel Cone Point Set Screws that are M8 x 1.25 mm thread, and 16 mm long (McMaster cat 91217A315, $7.85 for 10). 



DSC01512 showing the orientation of the 2/0 wires parallel to the axis of the motor and the difficulty in preventing some of the wires from bending back during insertion.  The Hyper9 bolts are M10-1.5 x 16 mm.  Without washers and locknuts, the threads must not insert more then 16 mm.  



DSC01515 picture of Odyssey Battery Copper "L" Adapter Terminal Brackets Kit (Yamaha Rhino / BMW) purchased from Seven Saturdays Motorsports (714-523-4357) for $14.99 .  The brackets are copper and 0.1245" thick and 0.502" wide.  The legs are 0.9285 (long) and 0.7656" (short).   Although for battery use, these brackets were too small for our application.  They were used as templates for the larger "L" brackets that were later made. 



DSC01526 of the EVWest RING-2/0-1/2 lug.

Commercial heavy duty ring terminal lugs were purchased from EVWest.  Part numbers RING-2/0-1/2 (1/2" of M12) and RING-2/0-5/16 (5/16" or M8).  Both sizes of terminals were priced at $2.90 each so there is not financial motivation for reinventing them.   

                                                                            

                                                           DSC01525 of the RING-2/0-1/2 lug.

The OD of the 2/0 tubing section is on average 16.44 mm and the inner ID is on average about 11.88 mm (the tube is slightly oblong). This opening is slightly larger then the Home Depot lugs (DSC01510 above) making the 2/0 wires easier to install.
Overall length is 59.3mm for 2/0-1/2, or 53.29 mm for 2/0-5/16
Tab is 23.04 wide by 25.0 mm long
Tab thickness is 4.54 mm.
Bolt Holes available in 3/8" or 5/16" or 1/2".

The lugs appear to have been made from a 2.2-2.3 mm wall thickness copper tubing that was then crimped flat at one end (note the seam at the edge in the far left image of DSC01525), drilled for passage of the attachment bolt, the tab end rounded, and Tin plating applied either by plating or hot dip.  The 2/0 wire entry is beveled, and since all of the lugs are slightly oval, it is probable that the edges were beveled prior to pressing.




DSC01529 showing both the plane of the base of the fitting and the score line just to the right of center.  If the fitting was pressed flat one might expect the tab on the left to be in the center line of the tubing.  Instead, there must be a fixture that holds the tubing in place and allows the press to asymmetrically compress the tubing on the left side.  The score line suggests contact on the edge of a clamping fixture.




DSC01531 showing the score line (middle right) on the underside of the fitting that was probably caused by the fixture that the tubing was clamped to during the press operation.  There appears to be a similar crease line internally suggesting that a rod was inserted prior to pressing.

 The 2/0 wire has a practical bending radius of about 2" and depending upon the orientation of the controller relative to the motor, the straight out lugs can pose some challenges.  Alternatively, one may use 45 or 90 degree 2/0 lugs (DSC01550 and DSC1549 below) for greater flexibility in the orientation of the cables. 



DSC01550 of the 45 degree terminal lug.



                                                    DSC0549 of the 90 degree terminal lug.


                                                                                    

        DSC01527 of  model YQK-120 EVWest hexagonal crimper (catalog number CRIMP at $68.00).

Model: YQK-120
Crimping Force: 12T
Crimping Type: Hexagonal crimping
Stroke: 14mm
Length: 425mm
Package: Plastic case
Crimping Range: 10-120mm
AWG Crimping Range: 6 AWG - 4/0 AWG
Dies: 10, 16, 25, 35, 50, 70, 95, 120mm

 (updated 2/7/2023)   EVWest indicates that they use the 95 mm die for crimping 2/0 wire.




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