Backpack battery. What amp wire?

[Tinker]

One of my kids wants to use a front hub kit ( inc controller) on a bike and borrow a battery until he (I) can afford it. This is no problem but I'm not certain what amp wire to use from the batt' to the controller, I have a reel of thinwall 30 amp twin or 41amp single.
What's best?

 

[NRG]

30amp will be more than enough...is it single or multi-core....flexibility will be a factor as will joint stress...

 

[Scimitar]

One of my kids wants to use a front hub kit ( inc controller) on a bike and borrow a battery until he (I) can afford it. This is no problem but I'm not certain what amp wire to use from the batt' to the controller, I have a reel of thinwall 30 amp twin or 41amp single.
What's best?

If you expressed them in normal sizes, ie, cross sectional area, it would give a better idea. 30A or 41A is more or less a guide and the heavier the better, but bear in mind the working voltage of a bike. 24V or 36V - the heavier cable will offer less volt drop under load and every volt is important at these levels. Volt drop is important in mains use, but it has less of an impact. Are these mains cables or automotive ones?
Whatever; the more flexible of the two might be the best choice anyway; there's nothing more annoying than an intermittent fault caused by a broken conductor.