3v should be fine. That's the same as a pair of batteries would push. Some clones have 3 batteries in the charger, and push 4.5 volts. I personally feel that's a little too harsh, but my point being that the rechargable batteries take it.
...crazy man, crazy...dig it. crazydave'sGallery Ratfink says: "Man, it's the craziest"