My iPhones battery warnings

Ok, so my iPhone only gives me warnings at 10% and 20%, can I change that? And how?

I doubt you can change that. As it is, a phone only notifies when the battery level is really low. For rest of the time, you can keep looking up on the bar on top of the screen for the battery level.

However, there're a certain battery monitoring apps in the AppStore that allow you to set a reminder level. You can look up the AppStore under 'battery' and judge for yourself which app suits you.