7 3/8 x 9 1/4 T echnical / Build Your Own Electric Vehicle / Leitman / 373-2 / Chapter 10
C h a p t e r 1 0 : E l e c t r i c Ve h i c l e C o nve r s i o n Curtis quickly replaced under warranty—Jim did a thermal and mechanical redesign on the entire control electronics area. Figure 10-36 shows Jim’s “magic box” redesign. In this incarnation, everything is accessible from the outside, the two power cables bolt on, the two instrumentation cables plug in, and the two fuses are accessible from outside the case. Figure 10-36 shows a front view of the thermally redesigned controller mounting. In this design the controller is flipped over and a heat sink is mounted to its bottom (silicone thermal lubricant was spread over the area for the highest heat dissipation efficiency). The combined package was then centrally mounted in the location of maximum engine compartment airflow. Figure 10-37 shows a driver-side view: charger (in the original location), newly inverted controller with heat sink on top, and revision two of Jim’s magic box. When the replacement controller from Curtis was plugged into the new layout, everything worked fine with no more thermal cutout. Figure 11-38 shows the result.
Further Improved Cooling The eternal mechanic in Jim was still not satisfied—he wanted to have controller cooling independent of the vagaries of engine compartment airflow. So he added the fan and directional cooling shroud to the top of the heat sink (Figure 10-38). He also widened the mounting space between his magic box and the controller (everything is now mounted on the common heat sink aluminum plate), and relocated the battery charger to the passenger side fender well—all to maximize cooling and airflow.
Figure 10-37 “Magic box” and controller , driver-side vie w.
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