battery life

So I was looking for batteries for my wii portable and I thought, why couldn't I just use the battery from a wii u or some shit, so I found this battery on Amazon that is a supposedly enhanced Wii U battery, so can any of you pros let me know if this is a suitable battery for a portable wii...

I know I've asked quite a bit of questions however, I was wondering about how much power a portable Wii would consume with a 5 inch (diagonally) screen with everything else usually in a portable like a Wii and fan etc.