What does increasing amps do?

[Volusia25]

My Ebike has a Bafang SWX02 hub motor, KD58c LCD and 13ah 36v battery.

I noticed on the LCD display under advanced settings, you can change the level of amps. Stock is set at 15 amps. What would happen if i increase or decrease this level, and by how much can I do so? It is a UK restricted bike to 15mph
Thanks

 

[jazz]

Increasing amps would allow you to have more torque and higher speed but could also have shorter battery life