Battle Points are points that you get after you wins a battle.
The points received may vary depend on battles.
These can be exchanged for prizes if you have enough BPs.
You can only get them if you are rank 1-3 (black/red, gold and silver skull)
If you lose a battle, you lose an amount of BP equal to half of the BPs that your opponent gets.
This is the example:
Player A won against Player B. Player A is an 1337 that is a rank 1 player, while Player B is a n00b that has no wins at all, but heck, he is a rank 2. Player A gets 2 BP while Player B loses 1 BP.
(tries to be a n00b) sorry for bad english