Ah.. you've got yourself a nice roll of aerial cable, it's the very cable the utility company uses from the transformer up to your house. Most all of the aerials for this purpose are aluminum these days due to cost and physical weight of such hefty wire, this stuff is perfectly appropriate to use from your panels or genny back to your house, shop, or power shed.
It will carry 48 volts just fine. You will need to use one size larger aluminum cable than you would copper because aluminum has higher resistance due to its lower electron velocity. That #4 you have will be good to about 50 - 55 amps, for runs over 100 - 120 feet keep it just under 50 amps for a little thermal head room at your splices.
Do NOT use aluminum wire in the house... cats and copper make good indoor pets, cattle and aluminum do not!
YES, aluminum does corode, corroded aluminum has a fine aluminum oxide powder covering it... if your not making a connection on a given area leave the thin layer of corrosion in place, it will protect from further corrosion... aluminum is a little unusual in that respect.
Treat it like the power company, use wedge clamps on the bare conductor and loop the bale over a solidly anchored insulator. Make your terminations and transition to copper outside, use a separating split bolt and dope it with NOALOX or similar compound (dope the copper too in a transition joint), tighten down, wipe excess compound off the insulation and wrap the joint in cloth or UV stabilized plastic electricians tape. The split bolts needs to be rated for mixed copper/aluminum connections.. basically meaning it won't expand and contract to much with thermal changes.
Just take these steps and aluminum wire can be a cost saving friend for those long runs back to the battery.
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crashK6
