I haven't tried using rechargeable batteries on the controller. It requires 8 of course, and I can get that many alkaline ones for $2.

Most chargers will only take 4 cells at a time, good reliable rechargeables are relatively expensive and so are fast chargers. You have to spend quite a lot, before you can even think of savings. At first, I would avoid possible trouble and save time by using fresh alkalines. If you have any problems -- at least you know the controller batteries are OK.