Although I do prefer the great new and fresh scholarship coming from Latin America regarding its wars of independence, there are some good picks in English. A good general overview and introduction is John Charles Chasteen's Americanos: Latin America’s Struggle for Independence (Oxford University Press, 2008). It's shorter than I would have liked it to be, but it's a good way to get started and to draw further reading from. I would however recommend that you focus on individual countries seeing as the wars looked vastly different.