I have a long set of 1 AWG cu-al jumper cables that work great and I know they are more like #3 or whatever cu. They are very flexible even when frozen.
I also got a set of the same type of 2 AWG cu-al jumpers and cut off one end to use with my 100a converter to make it into a portable charger. I had to trim the ends of the wires so they would fit into the converter's terminals.
The wires are a million silky fine threads each with cu over al, so that is why it is so flexible. Quite different from the usual stranded cu wire I have worked with.
The price is right for the cu-al versions, and so long as you know what you have there and what you want it for, there is no reason not to buy it- at least in my experience. YMMV.
