I can say that I've been playing with my Wii on it's original batteries for a time period exceeding 25hours and it's still got a half charge. So who knows, it's going to differ from person to person depending on their hours used, and what games they play because of the power requirements for specific tasks versus others and how much the game makes use of the speaker and all that stuff. Not to mention each individual batteries charge is a little different than others. You could have two 1.5V batteries, yet one is actually 1.2 V and holds charge real well, where as the other could be 1.7 and lose charge quickly. There's dozens of variables in there.