High currents and Copper vs. Aluminum

For this post, I'm going to concentrate on just the in-wing battery packs.  They are by far the largest packs with the heaviest load.  The wings hold 74% of the batteries, which means they need to supply 74% of the current for all possible modes of operation.  Due to the nature of the twin design, there are several loads to consider. All loads are per pack

Normal Cruise - 57A

Normal TakeOff - 180A

Single-Engine Climb - 310A (74% of controller maximum 420A)

So worst case we need 310A supplied from one battery for up to 2 minutes.  The runs from the battery to the controller are somewhere around 2m.  Each battery needs its own run of pos & neg, so 8m of wire is capable of providing 310A over 4m (total run length).  Wire gauge charts recommend 2/0 ("00") as the appropriate AWG for this load. That's about 30lbs of copper!  That's a _LOT_ of copper.  But for large loads, there is an alternative... Aluminum.  Aluminum has a higher resistance, so we'll need a bigger wire, but it's 5x lighter than copper.  So the same run in 4/0 ("0000") is 4 lbs.

What's the catch?!  Aluminum as a conductor is not all good news.  There are three (maybe two) areas of concern, Aluminum, relative to copper, is brittle. It must be well secured through the entire run (especially the connectors) and as vibration-free as possible or the wire will snap.  Second, aluminum suffers from oxidation effects which lead to poor connection and potentially fire, so all connectors must be cleaned, coated with a "noalox" corrosion inhibitor compound.  And finally, all of the aluminum wiring and connections will need a regular inspection for the above reasons, where copper would have been installed and forget it.