Andy, i remember when wiring houses, someone introduced aluminium cable. 4 mm was used in place of 2.5 and 1.5mm was used to replace 1.0 mm. This was due to the increased resistance of the aluminium. Within about 18 months,it was declared as a rubbish idea due to conductors snapping and corrosion between the brass terminals and the alloy.I used it in a pigsty and the cable open circuited all over the place as the ammonia from the pigs got into it.
Cant beat copper for wire even after 100 odd years. I liked the old imperial stranded cable which was much better than the metric introduced in 1971.
The cable i have for the scooter is multistrand jump lead cable at about 6mm. Should improve a lot even if it is just 500mm long.