Street DreamsCC 10+ year member
CarAudio.com Elite
Your correct, after looking again it was in the 60% range
here is a basis to go
Electrical Conductivity – The Electrical conductivity of aluminum is roughly 60% of copper. The resistivity of aluminum is 1.64 times that of copper. Comparing a copper bus bar carrying 1000 amps of current and having a cross sectional area of 1 square inch (4” x ¼”) to an aluminum bus bar needing to carry the same load current. The aluminum bus bar would need to have a cross sectional area of 1.64 square inches (5” x 3/8”). Considering that applications generally require both charge and return bus bars it is easy to see how space and airflow characteristics of the equipment may be influenced by the use of aluminum.
Cost – With copper being approximately 2 to 3 times the cost per pound of aluminum it is at first glance easy to see why it would make sense to use aluminum whenever possible as a substitute for copper. This is especially true for applications where space is available for the increased bus bar size. However there must be careful design considerations made when making this choice. Factors such as working environment, product reliability, service lifetime, and scheduled maintenance all are critical factors that must be looked at when considering using an aluminum bus bar.
This was the reason I had went thicker and wider bars in my Caravan and alot thicker in the blocks on the Astro.
