How do u know when the batteries in the wireless controller is dead?

I don't want it dead while im still playing games.How do u know when the batteries in the wireless controller is dead?
If it's for 360, press the center button and on the side menu it shows the battery life up top. It also flashes way before it dies.





You should invest in the play and charge kit, it's worth it.How do u know when the batteries in the wireless controller is dead?
on my wii it flashes a warning when u start a game to say the batts r low n to change b4 playin.
well it depends, if youre playing with a 360 controller, then press the center xbox button on ur controller and it will show you your battery life in the top lefthand corner. same thing with the wii, and probably other systems.
if you press the center button on the controller (before it is dead) the normal pop up window will come up. On the upper right corner, there is a battery meter.
when my 360 contorllers batttery is low it the 4 lights blink repeatedly