AWG 2 not needed in your RV3
snipped
On the RV-3 we certainly will examine a #4 cable for weight. And be willing to "experiment" and see if it works (or alternatives).
I am not saying #4 will be OK, but worth researching (as is the "Super 2" or whatever).
Andy
Andy,
AWG 4 is the recommended starter/main cable size for RV3, 4, 6, 7, 8 & 9 models with the battery located in the front. I'm not familiar with all the possible locations for the battery on the 3. I do know that the stock location for the battery on the 4 [2 place variant of the 3] is in the front.
Vans only recommends AWG 2 cable for the 8 & 8A, IF you put the battery in the rear. This is done to offset the voltage drop during starting, caused by the longer cable.
Regarding using alternate types of cable. The welders cable mentioned by some, has one advantage. The rubber insulation is very thick and flexible. This is useful for use between the battery and main contactor and ground. The stiff Tefzel insulation in Mil Spec 22759-16 wire can cause failure of the battery terminals if it creates side loads on those terminals.
The downsides to welders cable are that it is heavier than Mil Spec wire and it's copper strands are not "tinned" [coated with solder] This lack of "tinning" would only be an issue for planes operated in or near salt water environments. For planes used in those environments, a better alternative would be marine cable. It also uses a soft insulation, but is "tinned".
The CCA wire offered by Perihelion Design does offer significant weight savings. That said, it also lacks the "tinned" strands of Mil Spec and marine wire. It's insulation does not offer the same resistance to damage that the Tefzel insulation of Mil 22759-16 wire offers. [FYI, the car manufacturers use Tefzel insulation on more and more parts in your car] I'm going from memory here [which is sometimes faulty]. While the CCA wire uses an insulation used previously on aircraft wire, I seem to remember that if exposed to flame, it creates a nasty smoke. Can someone who is using the CCA wire verify what it's insulation is made of?
Once you understand the advantages and disadvantages of each wire choice, you will be making an educated decision based on your needs and risk tolerances.
Charlie