i just bought a 1800mA battery for my Hero, which is supposedly longer-lasting than the stock 1500mA battery. I haven't noticed any difference in battery life. What I have noticed, however, is that the Mugen battery has no mechanism, not even the slight indentation of the stock, to allow removal of the battery. I had to use a knife, or other sharp instruments, to take the battery out. Needless to say, I accidentally sliced up myself. Who designs these things anyways?